This article is an introduction to four articles exploring the theme of purpose in biology. For purpose as ‘meaning’ in individual lives see Meaning
‘It is absurd to suppose that purpose is not present [simply] because we do not see an agent deliberating.’
Aristotle c. 360 BCE (Phys ii.8,199b27-29)
‘From the point of view of contemporary biology, both vitalism and teleology are stone-cold dead’
David Hull 1969, p. 269
David Hull 1974, p. ix
Michael Ruse 2003, pp. 287-288
Structure (design) in the service of function (purpose)
Shared X-Ray image of stingray
Courtesy loctrizzle – http://imgur.com/gallery/bZbHmJA
Accessed – 22 Mar 2019
One key problem in the history of scientific ideas, often thought to have been laid to rest by Darwin, is the question of design and purpose . . . in the universe generally, but more specifically in biological systems. This is the question of teleology.
Teleology is the study of the goals, functions, ends, and purpose of things – of all things – from the universe and inanimate objects like chairs and table-forks, to organisms and their behaviour, their organs, biological processes, even the path of evolutionary history.
Natural teleology (sometimes called bioteleology) focuses on purpose and design as it applies to nature.
Today teleology is generally passed over as either a confusion related to the pre-scientific ideas of Aristotle, or a religious hangover associated with intelligent design theory and creationists. It is largely ignored by contemporary science. Perhaps surprisingly, a journey through the history of ideas can present us with some unexpected challenges and insights into this ancient idea.
The first section describes what Aristotle’s natural teleology actually claimed, and its role in his scientific methodology, including an examination of the ways in which his conclusions differed from those of his pre-Socratic natural science predecessors.
The second section looks at the scientific and social impact of Darwinism in the 19th century, the relationship between Darwinian natural selection and Aristotelian natural teleology, and how Darwinian gradualism unified matter in a historical transition from the inanimate to the living, the sentient, and rationally self-aware. Also, how Darwin’s natural selection provided the scientific grounds for teleological realism that were lacking in Aristotle’s natural teleology.
The third article examines in more detail the way that teleological selection processes introduce rudimentary value (normativity) because they are selecting ‘for’ something. Also the way that the ends or goals of selection are beneficial, functionally desirable or, as Aristotle said, ‘for the better‘. This is tied into a system of biological normativity which claims that the purpose of all living organisms is ‘to survive and reproduce‘. This general biological maxim is then related to the specific human traits of language and intellect harnessed to foster human happiness and flourishing which serve as the foundation for a universal and objective ethical system that can assist us in the management of the community of life on planet earth.
The fourth and more speculative article explores the way that the meaning of words can track the nature of matter in its evolved complexity and how this effects our understanding of words like ‘reason’, ‘cause’, ‘selection’, ‘purpose’, ‘function’, ‘design’, ‘intention’, and ‘value’ in the light of a gradualist interpretation of change in the material world. It examines the transition from reasons to conscious deliberation; from order to design; and from selection to purpose, value, and intention.
There is a further objective to these articles about ‘purpose’ and that is to introduce the reader to Aristotle (384–322 BCE), the founder of biology – if not the founder of science itself. Greek philosopher Aristotle is best known for his work on logic, ethics, and politics but this ignores his scientific work, especially his biology.
Richard Owen, an eminent anatomist at the British Museum in the 19th century, introduced a survey of Aristotle’s zoological studies by declaring ‘Zoological Science sprang from his (Aristotle’s) labours, we may almost say, like Minerva from the Head of Jove, in a state of noble and splendid maturity‘.
As a biology student the name Aristotle was never mentioned to me – in fact classical learning was completely absent from the science curriculum except for a few passing references to ancient astronomy, mathematics, and medicine. It is difficult to account for this. During the Middle Ages, as universities were established in Europe, Aristotle dominated the curriculum of monastic scholars. For centuries a good education in both arts and sciences was grounded in the classics. No English gentleman of the 18th and 19th centuries was regarded as fully educated until he had completed his education with a ‘grand tour’ of Europe to admire the splendours of the Greco-Roman world.
In the Early Modern period a break was made with ancient times as the modern mind shed its deference to the classical and religious wisdom of the past. Obvious errors had been made and one of those glaring errors, we were told, was Aristotle’s mistaken attribution of purpose (teleology) to nature. There was also much to despise about the classical world – its cruelty, mistreatment of women and slaves, rigid hierarchies, its democracy in name only, and its arrogance. The impression I was given was that, in science at least (classics have remained an important part of th humanities curriculum), we had learned from these people and moved on. There was neither the time nor the need to look back. Then in the proliferation of academic disciplines that occurred in the 19th century the history and philosophy of science becomes a subject to be pursued in a different building from the sciences themselves.
Aristotle still deserves the attention of biologists, and indeed all scientists, and for many reasons. Firstly, he takes us back to the dawn of systematic thinking about the physical world, to the first early attempts to explain in a carefully reasoned way, and without deference to the supernatural, the way that the material world works. Our inheritance of cumulative knowledge is taken so much for granted that we ignore what it must have been like taking the first tentative steps into naturalistic explanation. Aristotle’s teleology, for example, carefully assembles and critically examines the theories available in his day, subjecting them to a rigorous critical analysis in the search for reliable scientific explanations and therefore secure knowledge (episteme). This required proper scientific ‘demonstration’ as he called it. Aristotle’s theoretical critique of scientific methodology is outlined in his Posterior Analytics which is accompanied by several works on the practical aspects of biology – including the first recorded dissection of animals to examine the way their bodies worked.
Aristotle’s student Theophrastus, who followed Aristotle as Head of the Lyceum in ancient Athens, wrote the world’s first treatises on plants, the first botany text books. Today these works are unremarkable but they were the foundational materials on which later plant science was built.
The solid foundation of critical scientific thought laid down by the ancients is easily ignored in the light of the great achievements of the later Scientific Revolution. A recent history of science, for example, ‘The Invention of Science‘ (2015) by scientific historian David Wootton passes over the ancients (and teleology) to place the origin of science firmly at the start of the Scientific Revolution of the 16th and 17th centuries.
Modern science was invented between 1572, when Tycho Brahe saw a nova, or new star, and 1704, when Newton published his Opticks … there were systems of knowledge we call ‘sciences’ before 1572, but the only one which functioned remotely like a modern science, in that it had sophisticated theories based on a substantial body of evidence and could make reliable predictions, was astronomy, and it was astronomy that was transformed in the years after 1572 into the first true science … it had a research program with a community of experts
The great achievements of the Early Modern period notwithstanding, it is difficult to read Aristotle’s science without realizing that Renaissance and Enlightenment European scholars were standing on the shoulders of this analytic tradition. Not surprisingly many of Aristotle’s ideas look strange, misguided, and outright wrong today. He relied too much on logic and not enough on experiment and observation. But we can make too much of this. His Renaissance successors, I believe, owed him more than they wanted to give. Aristotle distilled much of the wisdom of the ancient world into subjects and academic treatises that have stood the test of time. He was perhaps the greatest ever polymath.
Philosopher Bertrand Russell described him thus:
‘… after his death it was two thousand years before the world produced any philosopher who could be regarded as approximately his equal … he is the first to write like a professor: his treatises are systematic … he is a professional teacher not an inspired prophet … his work is critical, careful, pedestrian, without any trace of Bacchic enthusiasm … the errors of his predecessors were the glorious errors of youth attempting the impossible; his errors are those of age which cannot free itself of habitual prejudices’ … ‘Aristotle is the last Greek philosopher who faces the world cheerfully; after him, all have, in one form or another, a philosophy of retreat‘.
In the following articles I present the case that Aristotle’s teleology was essentially correct – it makes sense today as it did in his own times. The Early Modern period mistakenly conflated teleology with the superstition and supernatural beliefs so pervasive in those times. The theistic interpretation of the world challenged by Darwin has subsequently been replaced by an anthropocentric one in which humans have been regarded as the source of natural purpose and design.
Aristotle was a student at Plato’s Academy (the model for today’s universities) where astronomy and mathematics were the focus of interest. Though respecting the study of the heavens and the abstractions of number, Aristotle was at heart an empiricist, shunning other-worldliness for what is here on earth, especially living organisms. Indeed, in many ways he regarded biology (not maths, physics, and astronomy) as the point of departure for science. Much of this stems from his ‘four causes’ and his examination of the order we find in the world, especially the order of living things, and the way this is functional – directed towards ends, his telos or ‘purpose’. But it was largely because of his telos that Aristotle would fall out of scientific favour.
Plato is renowned for the beauty of his Greek prose. Aristotle had a similar reputation in his day but the majority of his works have been lost. Those that remain come down to us as difficult lecture notes presumed to be both unfinished and specialist documents. Plato’s writings were more literary, being in the form of a dialectic, narrative or parable with the meaning left open for the reader to discover or interpret. Aristotle’s writing is more scientific, consisting of summaries, analyses and systematic development – but he could also write in an engaging way. Aristotle’s Lyceum tried to bring the cosmos and abstract mathematical concepts down to earth. We see some of his engaging prose style in this exhortation to his students of biology:
‘It is not good enough to study the stars no matter how perfect they may be. Rather we must also study the humblest creatures even if they seem repugnant to us. And that is because all animals have something of the good, something of the divine, something of the beautiful’ . . . ‘inherent in each of them there is something natural and marvelous. Nothing is accidental in the works of nature: everything is, absolutely, for the sake of something else. The purpose for which each has come together, or come into being, deserves its place among what is natural and good’ . . . ‘The nature that crafted them likewise provides extraordinary pleasures to those who are able to know their causes and are by nature philosophers’
Aristotle – De Partibus Animalium (The Parts of Animals) 645a15
Aristotle’s sentiments are aptly referred to as ‘The Invitation to Biology’. The teleology that is buried in his sentiments is only now, after over 400 years of rejection, gradually being restored to scientific respectability through a philosophical position outlined here as teleological realism.
. . . continued . . . in the following section . . . Aristotle to Darwin.
1. Aristotle to Darwin
When we look closely at nature it becomes evident that almost everything has a function or purpose. The simplest living organism is a masterpiece of design that is more exquisitely crafted towards functional ends than any human artefact. Philosopher Aristotle famously declared that ‘Nature does nothing in vain‘ . . . and how could we possibly disagree?
Purpose, as functional design in nature, is easy to observe and readily understood. We all know why animals have eyes and ears and fish have fins. In daily life we assume without question that birds have wings to fly, spiders build webs to catch flies, and plants have coloured flowers, scent, and nectar to attract insects and birds. Almost every part and process of our own bodies has a clear purpose. In fact we feel triumphant when we find something in the body that doesn’t have a purpose . . . ahah . . . the appendix . . . and mens’ nipples!
It is only when we delve into the source of all this intricate and fine-tuned functional complexity that suspicions about purpose in biological systems begin to surface.
From the dawn of the Scientific Revolution up to the present day the idea of purpose in nature has been under challenge. So what is the problem – why does science currently take such a dim view of nature’s patent purpose?
Ajania pacifica – Silver & Gold Chrysanthemum – from Japan
Growth tips of a single spreading plant, each tip is superficially identical to the others but differing slightly
Photo – Roger Spencer
It all seems to stem from two related questions. First, ‘Who, or what, inserted all this goal-directed design into living things . . . where does it all come from – what is the designing mechanism‘? But second, and more tricky, a problem that still baffles scientists and philosophers: ‘How can something that lacks intelligence, like a tree or a worm, possibly be said to have purposes or to demonstrate design?‘
These two questions boil down to a single metaphysical question (a question about the nature of reality). For the scientist this is a question about our scientific ontology (what actually exists). Are purpose and design in nature real or only apparent: are they a part of the fabric of the world or are they something we impose on the world with our minds. Are they mental constructs?
This first section examines Aristotle’s contribution to this debate, the second will consider the subsequent impact of Darwin’s theory of natural selection.
For summary purposes, in this and the next section the major theories about teleology – where it comes from (or not) – are stated as general principles; there are eight in all.
Order, agency, & the pre-scientific mind
The problem of purpose and design in nature relates to a broader scientific endeavor, that of accounting for the order we see in the world. There is no self-evident reason why there should be order around us and not chaos. If everything around us is a product of accident and chance, as we might expect, then why isn’t it all random and disordered? But then, if the world were chaotic it would be unknowable. And when we examine nature closely it is not chaotic at all: instead we have objects as miraculously ordered, integrated, and complex as human beings. So where does this order come from and why should it be there at all?
Our hunter-gatherer ancestors of pre-history were mostly animists, believing the world to be inhabited by spirits of various kinds – in rivers and springs, trees and forests; these spirits and gods made thunder when they were angry, sent rain to water crops, plagues to punish, and so forth. In the course of human history these spirits seem to have gradually withdrawn from the world, moving first from the lowlands to maintain tops (the Greek gods), then into the sky to finally depart the confines of space and time. An uncomfortable question now arises. What if there are no spirits and gods . . . who or what is then in control of everything?
The concern with order and disorder was a central problem in antiquity. Order and Chaos in the belief-system of the ancient Egyptians of the Old Kingdom (c. 2375 BCE) were represented as a symbolic ritual battle between the opposing physical and social forces of Ma’at (order, harmony, truth, balance, and justice) and Isfet (disorder, confusion, lawlessness, and evil). Greek mythology described chaos as a formless and empty void out of which the gods forged the orderly familiar material world of daily experience.
But it is not just living things that exhibit order and pattern: matter is organised into the different elements and chemicals as neatly presented to every chemistry student in the Periodic Table. Rocks form layers in the earth’s mantle. Stars follow regular and predictable motions in the heavens, the Sun rises each day, and the seasons come and go inexorably, again and again. That there is structure and order is undeniable, but how do we account for it – how did it come to be?
Throughout history we have found a simple answer to the question of order, design, and purpose in nature and the world. An object like a spear is designed to fulfil a specific purpose, to kill animals – but a spear requires a spear-maker, a designer. By analogy the order we see in nature is the work of a master-designer who is much more powerful and skillful than any human being, in fact it is a designer with super-human and supernatural powers. That designer must be God(s).
Sources of order & purpose 1 – Theism – The order and design we see in the world around us was imposed from outside by its Maker – God(s)
But by what means did God(s) impose this order and – even more worrying – what if there were no gods, what then?
In the West, ancient Pre-Socratic thinkers (c. 624-469 BCE), the first recorded proto-scientific naturalistic (non-supernatural) philosophers, looked for answers in nature itself. Order must have emerged in some way from the world’s fundamental elements: Earth, Air, Fire, and Water. These four fundamental ingredients of the universe were accepted by Plato, and Aristotle added a fifth, the aether, a substance that held the stars in their circular motion.
The presocratic philosopher Heraclitus had referred to the rational order of the universe as the ‘logos’ while philosopher and mathematician Pythagoras (570-495 BCE) used the word ‘Kosmos’ (Greek κόσμος) and, like other ancient Greek philosophers, he wondered how this orderly structure had arisen.
Also from the presocratic philosophers came the idea of nous, which can be interpreted not only as ‘mind’ but the orderliness that gives cohesive unity – identity that is distinguishable and definable. This was different from the later Greek soul as ‘that which gives life and animates’. Roman commentator Cicero pointed out in The Nature of the Gods that ‘the first human thinker to claim that the orderly disposition of the universe as designed and perfected by the rational power of an infinite mind’ was Anaxagoras. This nous was not a Creator producing something from nothing, ex nihilo, but more a shaper, fashioner, artificer or architect operating on the primal chaos – a planning or organising principle present in things.
Today we pass quickly over the order of the universe as the inevitable consequence of scientific laws or physical constants and dont pursue the question of why these laws and constants exist, or how they came to be the way they are.
Both Plato and Aristotle believed that Anaxagoras’s cosmology was incomplete. Their universe included not just order, but purpose – they claimed that the world was teleological – not just ordered, but ordered to achieve ends. The teleological universes of Plato and Aristotle were not however universes of conscious purpose. Plato argued for an unconscious but intelligent universe as did Aristotle although Aristotle’s teleology was usually discussed in relation to both the conscious and unconscious orderly purposiveness that we see in all living things.
It was Socrates (470– 399 BCE) who, according to his student Xenophon’s Memorabilia, first formalised an argument that used cosmic structure as evidence for a grand designer or God, this being the oldest recorded articulation of the famous proof for the existence of God, the Argument from Design or, as we know it today, Intelligent Design.
Philosopher Plato (c. 428– 348 BCE) was a deist. He refused to believe that something as complex as a human being could possibly have arisen by blind chance. How could the objects of the universe, especially living organisms, spontaneously self-assemble – there just had to be some organising principle and Plato called this principle the Demiurge which he construed as a transcendental supernatural force like a God.
The Demiurge wanted everything to be good . . . so far as that was possible, and so he took over all that was . . . in discordant and disorderly motion – and brought it from a state of disorder into one of order, because he believed that order was in every way better than disorder
Like prehistoric hunter-gatherer animists, who believed that spirits inhabited everything, the famous ancient Greek physician Hippocrates (c. 460-370 BCE) – of the doctors’ Hippocratic oath – believed in a vital force, inner spirit, or mystical pneuma (breath) that existed in our bodies over and above the physical matter. This was our source of energy and purposive drive – it was what distinguished a living body from a corpse, and living matter from inanimate matter.
Vitalism (both ancient and modern) proposes some kind of intelligence or mind-like substance influencing or inhabiting minds and the world. This supernatural force has been given many names including anima, pneuma, élan vitale, entelechy, panpsychism, nous (attributed to Anaxagoras (c. 500-428)), soul, and so on – but always as a non-physical supernatural entity inhabiting body, mind, or object rather like a soul or spirit, and often assumed capable of existing independently, departing the body at death to persist in a separate mystical realm.
Sources of order and purpose 2 – Vitalism – The purposive energy of living organisms exists as an inner (supernatural) force that is independent of physical matter
Vitalism is now discredited – partly because of the implausibility of such forces but mostly because they simply cannot be detected and studied.
Aristotle, like his predecessors, wondered how the order in the world had arisen and he noticed how structure in nature was always reaching for goals. Humans of course were always after something – food, drink, power, the Good Life, happiness, virtue, sex, and so on. But Aristotle was convinced that it wasn’t just humans that were purposive, it was everything in nature.
Following in the steps of his predecessors Aristotle continued the investigation of goals or ends as telos (Greek τέλος, telos , τελε-, end or purpose, and -λογία, logia) as a branch of learning. This tradition continues today as ‘teleology’ a word derived from the Latin form teleologia coined in 1728 by German philosopher Christian Wolff.
In true scientific fashion Aristotle began by reviewing the work of his predecessors. He notes that Empedocles (495-430 BCE) thought that the order we see in nature is simply a matter of luck or chance, arising randomly and therefore for no particular reason.
Sources of order and purpose 3 – Chance – purpose in nature arises in a random way by chance or luck
This Aristotle denied. The biological begetting of like from like, of functional complexity, generation after generation, was clearly not a matter of chance.
. . . all natural things come to be as they do either always or usually, whereas no result of luck or chance comes to be either always or usually . . . if then, these seem either to be coincidental results or to be for something, and they cannot be coincidental or chance results, then they are for something
By contrast the atomists like Democritus (c. 460–370 BCE) were materialists. They postulated a world made up of tiny indivisible atoms united to form the structured world we see around us, all as a consequence of inexorable deterministic natural laws. They, like many scientists today, saw no need to postulate unnecessary objects like purpose or final cause. Atomists were content with a metaphysics consisting simply of matter in motion.
Sources of order and purpose 4 – Necessity – purpose in nature is nothing more than the playing out of material and efficient causal determinacy
So how do purpose and design differ from mere causation? Aristotle acknowledged material deterministic causation, but insisted that if this were so there would be at least as many useless aspects to nature as useful: telos was still needed to provide a complete scientific explanation (what he called a demonstration). Natural teleology was a special kind of causation in which determinate changes were ‘for the better‘ or ‘for the best‘ – independently of human minds.
Aristotle, having examined all the prevailing theories of purpose and order, reached a new and different conclusion.
Intrinsic & extrinsic teleology
God was an extrinsic or external source of purpose and order.
Aristotle believed in God, but as an unknowable eternal and uncreated Unmoved Mover of the universe, perhaps similar to a physical force existing beyond space and time and therefore without human-like characteristics, and certainly without human-like desires or wishes. To think that such a being would be concerned with human affairs was human arrogance. So Aristotle looked for the source of order, not in some transcendental spiritual realm as Plato had done, but in the physical and material world of here and now. He disagreed with Plato by claiming that the source of the order we see in any organism is derived from within (intrinsically or imminently). Order derives from an organism’s ‘nature’ which acts like an inner craftsman – it was not imposed from outside by some intelligent agent like Plato’s Demiurge. He made this point by stating that ‘If the art of shipbuilding is in the wood then we would have ships by nature‘ (Phys. ii.8) the point being that the telos of a ship is imposed by humans from outside as an extrinsic teleology while the telos of an organism, its capacity to produce likeness again and again, is derived from within ‘by nature’.
Aristotle outlines what he means by telos in Book 2 of his Physics (Phys ii.8). His scientific curiosity had registered the deterministic character of natural processes, the linkage of cause and effect, and the high probability of particular outcomes given particular prior conditions. His telos in biology referred to the way that the development of living organisms followed a more or less predetermined path culminating in reproductive maturity as an end-point, or goal.
Aristotle had observed that like begets like (humans do not give birth to birds) in a predictable or deterministic way so, in this sense, natural development was ‘for’ something. From this perspective questions about purpose in nature were both legitimate and meaningful, they were not silly subjective questions because they had rational factual answers, so: ‘Why does an acorn exist – what is it for? – answer, ‘to become an oak tree‘. ‘Why does a boy or girl exist?’ – answer, ‘to become a man or woman’.
Some difficulty remains in interpreting, through the haze of translation, precisely what Aristotle was trying to say about telos and what his conclusions might mean for today’s biology – but here are some other quotes:
‘Organisms other than man ‘… make things neither by art nor after enquiry or deliberation … if then it is both by nature and for an end that the swallow makes its nest and the spider its web, and plants grow leaves for the sake of the fruit and send their roots down (not up) for the sake of nourishment, it is plain that this kind of cause is operative in things which come to be and are by nature.’ … ‘And since nature is twofold, the matter and the form, of which the latter is the end, and since all the rest is for the sake of the end, the form must be the cause in the sense of that for the sake of which’.
Loosely paraphrased in modern language as:
‘Non-human living organisms do not have conscious intentions but still demonstrate purposes as part of their intrinsic nature. It is in terms of what structures and processes are ‘for’ that we explain biological systems’
‘Where a series has a completion, all the preceding steps are for the sake of that’
Phys ii.8,199a 8-15
‘For those things are natural which, by a continuous movement originated from an internal principle, arrive at some completion’
‘In natural products the sequence is invariable if there is no impediment … It is absurd to suppose that purpose is not present because we do not see an agent deliberating’
Phys ii.8,199b 27-9
In De Anima Aristotle draws attention to the close similarity between the telos in nature and human conscious intention: ‘For nature, like thought, always does whatever it does for the sake of something, which something is its end‘.
Ends or limits (as resting places or completions but not necessarily total finality) provide points of stability around which to structure our thoughts. Ends are not confined to the goals of human intention but in living organisms they are an underlying requirement for meaningful and comprehensive explanation: the explanations of these ‘ends’ are what makes the biological world intelligible. Further, they are ends that do not necessarily imply conscious intention.
From what has been discussed so far it is clear that Aristotle had denied that purpose can only be understood in relation to intelligent deliberation, whether that of humans, the divine, or supernatural. He had also ruled out the possibility of luck or chance as a source of purpose, and he had noted that the deterministic necessity of natural law does not provide a satisfactory explanation of the purpose we see in living organisms.
We get a better insight into telos by looking at the four major ways Aristotle believed that we provide explanations of why things should ‘be‘. These are known as his four causes.
Aristotle’s four causes – the four major kinds of explanation
Aristotle tried to answer fundamental questions about the world by starting from the simplest possible first principles since this, he believed, was the path to reliable knowledge (epistêmê). So, for example, he asked How can we account for change (kinesis) in the world: why does anything happen at all? and ‘Why does this object exist, what is its reason for being?‘ He was deeply aware of the need to satisfy human curiosity. ‘Knowledge is the object of our inquiry, and men do not think they know a thing till they have grasped the ‘why’ of it (which is to grasp its primary cause).'(Phys. ii.5) In this he was following his mentor Plato, who had stated ‘ . . . philosophy begins in wonder. (Theaetetus 155c-d, tr. Jowett).
Aristotle wanted to provide compelling scientific or naturalistic explanations (his ‘demonstrations’) for phenomena in the world, and he proposed a toolbox of four ’causes’ (aitia) each being ‘something without which the thing would not be‘. This was a key part of his metaphysics – his ‘science of being’.
Aristotle’s account of change included his four causes combined with the notions of potentiality and actuality.
These thinking tools, Aristotle suggested, provided the major explanatory resources needed to investigate the natural world. They were scientific first principles, . They were not causes as we understand them but ‘be-causes’ or modes of explanation that provided reasons, or grounds, for existence and change.
1. What is it made of? (material cause) – ‘that from which’ – explanations given in terms of substance, matter, or parts
2. What is it? (formal cause) – ‘that which makes it what it is’ – Greek eidos. This has several slightly different senses: firstly, something’s shape, arrangement, structure, or appearance; secondly, its essential character or kind communicated by a definition; thirdly, biologically an inner species-specific capacity for functional organisation passed from generation to generation (like today’s developmental information contained in the genetic code)
3. What produced it? (efficient cause) – ‘the maker or mover’ – a mechanism of change equivalent to today’s ’cause’ as ‘what happened before’ (the initial trigger of change, a mechanical interaction like one billiard ball hitting another, or parents producing a child)
4. What is it for? (final cause) – ‘that for the sake of which’ – Greek telos. The purpose (fulfillment, goal, destiny, outcome) for something, the end to which it is directed.
Put simply, his ’causes’ answer the questions: what is it made of, what is its defining structure or characteristic(s), what is its method of production (how did it arise), and what is it for, what is its end? Not every answer required all four be-causes.
As an example we can use all four ’causes’ to explain a table as follows. The carpenter (efficient cause) selects a particular wood (material cause) to fashion into a particular kind of object, a table (formal cause) so that he has somewhere to sit and eat (final cause). Aristotle believed that material and efficient causes alone do not provide a complete explanation: it is the formal cause that gives an object structure and meaning and in the case of an organism the formal cause is its defining structure or organization. From the time of the Scientific Revolution mechanistic science, reducing science to the study of matter in motion, have regarded formal and final causes with suspicion.
A modern example is the way biologists have long argued about the best way to define the gene: should it be structural (material cause), positional (formal), historical (efficient), or functional (final)?
A strength of Aristotle’s four ‘becauses’ is that they are both static and dynamic . . . they include both past and present. They incorporate not only structure and function but also history and development by considering potentiality, actuality, and the temporal sequence of efficient cause. They explain the way things are now, but also account for change by explaining how they came to be. And their meaning allows some flexibility of interpretation (Aristotle himself points out that the Greek word aition as ’cause’ has various senses).
Formal cause is associated with the idea of ‘essence’, regarded by many today as an unnecessary or mistaken assumption about existence referred to as ‘essentialism’. Aristotle distinguished between the essential defining or key characteristics that determine what an object is as opposed to accidental properties that are peripheral: say the deforming effect of thalidomide on the development of a child.
For Plato the essence of an object (what particular things have in common – say the ‘catness’ of cats – was its Form as an abstract and eternal transcendental idea outside space and time. Aristotle thought that these ideas (also called universals) were not transcendental but in some way associated with the physical objects. It is easy to deny both claims; but remember that without these abstract universals it would be impossible to do science.
The idea of formal cause may be confronted by considering what it is that makes you you – bearing in mind that, it is sometimes said, every molecule in the human body is replaced in seven years? What is the material difference between a living body and its corpse?
Aristotle’s biographer Armand Leroi, an evolutionary biologist working at Imperial College, London, presents Aristotle’s causes in a schema that represents today’s biology in a very general way by equating material cause to biochemistry and physiology, formal cause to genetics, efficient cause to developmental biology and neurophysiology, and final cause to evolutionary biology and the study of function and adaptation. Leroi concludes that Aristotle totally transformed the transcendental world of Plato ‘ … by the time he was done, matter, form, purpose and change were no longer the playthings of speculative philosophy but a research program’.
Aristotle also noted that teleology has two parts, the ‘of which’ or aim (say, of an eye ‘to see‘, of a heart ‘to pump blood‘) and the ‘for which’ or beneficiary, the organism deriving the benefit. Today we would, in a general sense, regard the genetic code as the ‘inner nature’ or, to use Aristotle’s analogy, the ‘inner craftsman’ that provides the critical information whereby ‘like begets like’. We recognize ‘like’ organisms by their intergenerational similarity as the formal cause that gives them structure and meaning.
Sources of order and purpose 5 – Natural teleology – Telos – ‘that for the sake of which’. An inner nature, capacity, or principle of change that exists in living organisms as a function or purpose: the realization of pre-existing inner potential. Natural teleology has both an aim and a beneficiary
Natural teleology can be expressed in a more formal philosophical way as: ‘… the realization of pre-existing internal potential (as formal-efficient and material-efficient causation) through stages framed by conditional necessity’.
The realization of the form is the end state to which the efficient cause is intrinsically (non-consciously) directed – a condition of completion in respect to capacity or potential. Thus all change is the realization – the actualization – of potential. The idea of telos was Aristotle’s contribution to this philosophical discussion. It was telos that provided a focus for causal explanation: without it the phenomena under investigation would be simply dissociated facts of the universe.
Future causation has no place in science: the world is the way it is today because of events that occurred in the past or are happening in the present, not because of what is going to happen in the future. But in biological systems the future is always there as a ghostly presence. When we say ‘spiders build webs to catch flies’ we have an eye on the future as well as the past. Though humans can contemplate both past and future we cannot assume the same for spiders. And yet it is a characteristic of teleological explanations that they infer something in the future relative to what is being explained: that is, they explain the means by its ends as though the future is causing something to happen in the present.
What is going on here?
Students study to pass examinations. So are future examinations the actual cause of the studying? On closer inspection it becomes apparent that it is mental anticipation (the imaginitive reconstruction, in the present, of what might happen in the future) that is the real cause – a subtle but critical difference. In developing intentions or goals we explore imaginary futures in the present, this being a characteristic of our human conscious reasoning that we call foresight.
Humans can adopt both backward and forward modes of thinking, that is, we are capable of both hindsight and foresight. We understand purpose largely through this human ability to look into the future. When we examine and talk about other organisms we find it useful to adopt this forward-looking mind-set, seemingly treating living things as though, like us, they can anticipate the future.
Aristotle pointed out that final causes in biology, as the end points of processes, are last in any causal sequence: they do not exert an actual causal ‘pull’ from the future. If we infer what something is for from what it does – what its role is in the overall life of the organism – then completed processes and parts unsurprisingly become the starting point of functional scientific explanations and this is why they have explanatory priority. The point here is that there is a subtle distinction between our forward-looking explanatory order (the order we use for explanations, in which ends come first) and the causal order that gave rise to the biological traits being discussed. Paradoxically, in life (but not in explanation), purpose is a cause not an effect.
The materialist explains beneficial outcomes as the results of materially necessitated processes. But for Aristotle beneficial outcomes cannot be a matter of arbitrary necessity as we would expect in a world comprised simply of material and efficient causes. The material necessity operating in organisms can only be adequately accounted for by including formal and final cause.
Identifying final causes aids the search for material, formal, and efficient causes that are parts of a complete causal explanation. But the future does not provide the necessitating conditions for its own realization: it does not exert a ‘mysterious pull’ from the future. There is no backward causation. Final causes are direction-givers and ends, the limits of development necessitated by formal-efficient and material-efficient causation. They are part of the conclusion that is being demonstrated. Though they are given first in any explanation, they are the last in causal sequence . . . first in order of conception, last in realization.
In sum, formal and final causes provide the order, timing, and limits to processes and their stages. They have explanatory priority because they are a quick means of assessing the causally necessary antecedents.
The giraffe’s long neck – an adaptation for reaching – was not anticipated, planned, or influenced by the future – but there were pre-conscious reasons for it coming to be.
In confronting the problem of order in nature Aristotle had noted the regular character of causal necessity. This was as true of the inanimate world as it was of living organisms. Today we attribute this necessity to physical constants, the ‘laws’ of nature. So for Aristotle objects in nature were, in a sense, moving to their appointed places … apples falling to the ground, and smoke rising into the sky. But Aristotle knew, as we do today, that this was not the universe striving to reach goals in a human-like way, it was instead the inbuilt nature of things. Scientists today (like Aristotle in his day) study causal effects or ‘ends’ without necessarily assuming the agency of mind or intelligence.
But Aristotle also realized that the telos of animate nature, of living creatures, had additional special qualities. He was aware that the orderly design of crystals, the predictable behaviour of the solar system, the way water assumes the shape of its container, and the way that pebbles are graded by size on the seashore, are a different kind of order from the order we see in biology. In addition to the physical necessities that are part of the world of crystals, mountains and all physical objects. Living organisms had complex organization, they persisted by reproducing their kind, and they could be beneficiaries of purposes that promoted their survival and reproduction – even though these were not conscious needs and interests like those we associate with humans.
So, in the animate world we see adaptations as ends (effects) that have beneficiaries and in so doing telos becomes natural teleology. Function, design, and purpose arise in nature in the absence of an intelligent agent. Organisms can be beneficiaries even though they are unaware of their benefits.
Science proceeds o the assumption of causal necessity, of the connection between cause and effect (or end). Without ends or telos, explanation is empty, it is simply not possible. And where causal necessities (reasons as functional adaptations) entail beneficiaries, where they are ‘for the better’ then we are entitled to speak of processes being ‘for’ purposes.
Aristotle insisted that telos had nothing to do with either the divine or supernatural. The inner capacity or ‘nature’ of organisms is not some mysterious inner supernatural force, but neither is it the mapping of human intention onto nature as a metaphor for human deliberation. An organisms ‘nature’ ensures that like begets like (unless prevented from doing so), it is why human embryos become human beings, acorns become oaks, and, as he expressed it himself, ‘stars do not have feet‘. It is correct that we only appreciate nature’s inherent purposiveness because our human minds ‘see ahead’, but this does not mean that the purposiveness itself is in our minds. When Aristotle remarks ‘If, therefore, purpose is present in art, it is present also in nature. The best illustration is a doctor doctoring himself: nature is like that‘ Aristotle’s point is that the purposiveness we see in biology arises not from our minds but from a kind of ‘inner administrator’. Today we would say it comes from the information/instructions carried in our DNA. However, that is where the comparison ends. Clearly nature does not have conscious intentions.
The ancient world came very close to a theory of organic evolution. Here is a quote from the Hardie and Gaye translation of part of Aristotle’s Physics Book 2:
Wherever then all the parts came about just what they would have been if they had come to be for an end, such things survived being organised spontaneously in a fitting way; whereas those which grew otherwise perished and continue to perish, as Empedocles says his ‘man-faced ox-progeny’ did.
And my paraphrase of Hardie and Gaye (I hope you agree):
How do biological structures arise as though they are designed for a purpose? They persist because they are organised by nature in a purposeful way while those that are not organised in a purposeful way, like Empedocles’s man-faced oxen, will die out.
Sicilian pre-Socratic philosopher Empedocles (c. 490-430 BCE) thought that the various body parts we see in the animal kingdom had once all been mixed up but that ‘… the human head, by combining with the human body, brings about the preservation of the whole, but by combining with the ox’s body fails to cohere with it and perishes. For those which did not combine on proper principles perished. And things still happen the same way nowadays …’.
Interpretation of this passage about Empedocles is contentious but is discussed by author Armand Leroi who points out that the notion of selection in nature was probably ‘commonplace’ in classical times. Lucretius (99-55 BCE) in De Rerum Natura describes the way ‘The fertile young earth naturally sprouted with life forms, and the organisms thus generated were innumerable random formations. Of these, most perished, but a minority proved capable of surviving — thanks to strength, cunning, or utility to man — and of reproducing their kind‘. The sixth century Roman commentator Simplicius remarks that many natural philosophers of his day held this view (Physics, 371.33-372.11), so crude versions of natural selection were circulating at least 2000 years before Darwin.
The mechanism whereby purposiveness is acquired will be discussed in more detail in the next article … Darwin and after . . .
The links between teleology, human nature, sustainability and plants will become apparent later.
Pre-history – Animists believe that spiritual forces inhabit the physical world and animate living organisms
2375 – The Egyptian Old Kingdom societies believe in opposing universal forces, Ma’at as Order and Isfet as Chaos
624-469 – Pre-Socratic natural scientists seek the source of order in the world in the fundamental elements of Earth, Air, Fire, and Water
570-495 – Pythagoras refers to the ordered universe as Kosmos
500-428 – Anaxagorus teaches that the world is the product of an intelligent principle he calls Nous
470-399 – Socrates argues for the existence of God based on the self-evident presence of design, the Argument from Design
460-370 – Democritus claims that the world is composed of indivisible atoms and that these have, by chance alone, combined to form the physical objects of the world
410 – 370 – Hippocrates, founding father of medicine, teaches that the human body is animated by an inhabiting vital force
428-348 – Plato maintains that the order we see in the world is a consequence of an ‘ordering principle’ created by a God-like Demiurge
Several modern philosophers (see Meyer (1992), Johnson (2005), & Leunissen (2010)) argue that Aristotle’s attention and claims were not so much about deterministic causation (necessity), or the compatibility or reduction of one kind of cause to another, instead his claims stand or fall on the distinction between intrinsic and incidental causation. That is, he opposes the view that the development of animals and plants is in any way accidental: if their development is not coincidental then it this sense it must be for something, it is goal-directed, and natural teleology stands. This might seem like obfuscation and needs some explanation.
Teleology is diminished by comparing it to material necessity and chance. Teleological explanations do not explain away material necessity (Balme 1987c), reduce it to conditional necessity (Johnson 2005), or negatively constrain the realization of function (Lennox 2001a).
Philosopher Mariska Leunissen recognises two kinds of Aristotelian teleology: primary teleology, driven by form, and the realization of pre-existing potential for form ‘for the sake of’ through stages limited by conditional necessity and leading to ends that are needed to perform the vital functions of the organism; a weaker secondary teleology, driven by matter, as the use of materials that are not a part of the organisms vital functioning and not dependent on conditional necessity: they are secondarily co-opted by the formal nature of the organism. This secondary teleology is ‘for the better’ or to help the organism to ‘live well’ rather than being critical – like our hair – and depending on material availability rather than a pre-existing potential for form. But we need to know if the end point is the realization of existing potential for form (driven by form) or the use of available materials by material necessity (driven by matter). Both are goal-directed but the former are formal-efficient in primary teleology and material-efficient in secondary teleology.
 Philosophers have differed in their interpretation of Aristotle’s work, the debate too complex to follow up here (see Johnson 2005, Leunissen 2010). I have tried to remain faithful to the original text
 Science is, in its broadest definition, the study of order. Orderly structures and processes preceded human minds by more than five billion years. The arrival of order in the universe marked the introduction of mind-independent meaning which arises in matter, not the mind. There are reasons for order in the universe but only minds have reasons. Order begins with meaningful cause and effect where effects have causes as reasons.
For some philosophers (e.g. Dan Dennett) matter in orderly motion is insufficient for meaning. For them meaning only arises when there are agents, like organisms, that can extract and use information from the environment and therefore demonstrate purpose
See next article for references.
2. Darwin & after . . .
‘It is absurd to hope that another Newton will arise in the future who will make comprehensible to us the production of a blade of grass according to natural laws’
Immanuel Kant – Critique of Judgment – 1790
Chart indicating biological divisions, geological ages and major evolutionary events
Courtesy Evogeneao https://www.evogeneao.com
All things bright and beautiful
All creatures great and small
All things wise and wonderful
The Lord God made them all
Each little flow’r that opens
Each little bird that sings
He made their glowing colours
He made their tiny wings
Published in 1848, eleven years before Darwin’s On the Origin of Species in 1859
From at least the time of the ancient Greeks only a few people had seriously considered the possibility of species changing as they reproduced again and again over many generations. In Darwin’s (1809-1882) day this idea was called transmutation or transformism but its advocates had little evidence and so they were generally regarded as crackpots. How could organisms possibly change over the years? There was simply no explanation of how this could be done. Scientific principles of inheritance had not been established at this time so there was no known mechanism to bring about such a change, except possibly for the Lamarckian inheritence of acquired characteristics (e.g. that a blacksmith’s son would inevitably have bulging muscles like his dad) a theory that did not square with the facts.
The Darwinian Revolution
Then in 1859 Charles Darwin (1809-1882) published On the Origin of Species, the central argument of the book being his theory of natural selection which contributed to the English language the memorable phrases ‘survival of the fittest‘ and ‘struggle for existence‘.
Darwin’s momentous contribution was to provide a mechanism whereby species could gradually change over time. It was a totally different explanation of the biological world than anything before. Natural selection provided a coherent naturalistic (non-supernatural) answer to the question ‘How could the biological diversity of the world we see today have possibly arisen?’ Darwin gave us a compelling explanation of how the entire community of life, humans included, arose by descent with modification from a common ancestor. The evidence for evolution was overwhelming – drawn from geology, paleontology, biogeography, and anatomy, and subsequently supported by molecular biology and all branches of the life sciences.
What made natural selection so special was that it added a further ordering process to the ordering processes we call the ‘laws of physics’. About 3.5 billion years ago discrete and mindless aggregations of organic matter (proto-organisms) acquired the capacity for self-replication, varying slightly as they did so. This resulted in differential reproduction in respect to the surrounding conditions such that those proto-organisms meeting the requirements of their environments tended to persist under replication: those whose heritable variations made them better suited to their environments tended to be the ones that, over many generations, would persist since it was these that remained to survive and reproduce. Thus natural selection arises when self-replicating matter develops the capacity for ‘heritable’ variation. From one perspective this is a mechanical and statistical sorting process like the grading of pebbles on the beach by the tide: from another perspective it is a rudimentary process of selection that ‘benefits’ a living organism.
Darwin described the process of fitting into the environment as ‘adaptation’ and the process of gradual physical change to produce these adaptations as ‘natural selection’. Thus over numerous generations speciation would occur as organisms gradually changed into new species. Materially natural selection is an interaction between semi-autonomous replicating matter (an organism) and its surroundings (the environment). It is, in effect, a rudimentary process of auto-modification by feedback or ‘self-correction’ in relation to surroundings – an integral aspect of the organism-environment continuum (it extracts information from the environment).
Mathematically natural selection acts as a recursive sorting algorithm (used in evolutionary computation).
Darwinism coincidentally drew attention to what amounted to an Aristotelian tripartite material distinction: the set of all matter ordered by the laws of physics; the subset of living matter ordered, in addition, by the sorting algorithm of natural selection; and the further subset of living matter that had the capacity for foresight, hindsight, abstract reasoning, and self-awareness.
Because we humans possess foresight and hindsight we can recognize this as a sorting process akin to what, in human terms, we might refer to as a capacity for ‘self-correction’ in relation to surrounding conditions.
Sources of order and purpose 5 – Natural selection.
The mechanical sorting process whereby organisms better adapted to their environment tend to survive and produce more offspring. A mindless process generating purposive products.
For many scientists and philosophers the attribution of the word ‘purposeful’ and ‘designed’ to the products of mindless and mechanical natural selection is simply unacceptable.
From ladder to tree
Darwin’s theory deeply insulted the sensibilities of his day, undermining many widely- and tenaciously-held beliefs.
First, there was the conviction that species were immutable. Because each had been uniquely placed on Earth by God there was no reason why they should change. The idea that new species could gradually emerge over many generations was considered not only absurd but blasphemous.
Second, and even more insulting to the dignity of humans (the pinnacle of God’s Creation) was the implication that humanity had emerged in a decidedly undignified way from ape-like ancestors. For this suggestion Darwin was mercilessly lampooned in the newspapers by cartoonists who depicted him as a monkey.
Third, Darwin’s theory placed in question the imagery of one of Aristotle and Plato’s most widely-accepted ideas about the structure of the natural world, the scala naturae, the Great Chain of Being or ‘Ladder of Life’ as adapted by Christianity. This was a popular understanding of the whole of the Creation on Earth arranged hierarchically from higher to lower like the rungs of a ladder, and surmounted by its crowning glory the human being, eclipsed only by God.
While contemplating the origins of living organisms Darwin had drawn in his notebooks, not a top-to-bottom ladder, but a tree-like structure where humans, for all their magnificence, were not at the top of the ladder but at the tip of just one branch. The selective interaction between organisms and their environments had branched into many solutions. Darwin had replaced the popular metaphor of the living world as a hierarchical ladder with that of a radiating and diversifying tree.
Fourth, Darwin’s theory was profoundly disturbing because it undermined a universal human belief dating back into prehistory, the conviction that there was a supernatural and intelligent grand design to the living world, the universe, and everything in it. On the Origin of Species had removed the necessity for God as an integral part of our understanding of nature, and this changed human perception of the world forever.
Darwin argued convincingly that the entire community of life had arisen over many generations by means of an intelligible mechanical process of ‘self-correction’ whereby, over many generations, organisms could ‘fit better’ into their environments. He called this process natural selection. It was a mindless natural process that had taken an extremely long time, and it was a process whose steps we might never know in precise detail.
Before Darwin it was the general belief that everything had been created and placed independently in the universe by God as part of his divine plan. Darwin was a unifier who showed how all matter was related – the organic arising from the inorganic, and living organisms, the community of life, united by common ancestry. This historical and material commonality was reinforced when, in about 1930, the Steady State theory of the universe was replaced by that of the Big Bang, the entire universe exploding from a point source out of which all else had ‘grown’ or ‘evolved’, humans being built from stardust. Perhaps unwittingly, by describing the interdependence, interconnectedness, and intergrading of everything Darwin had reinstated Aristotle’s organismic metaphor of the universe. The universe as machine was upgraded to at least a computer but with an organic interconnectedness more akin to an organism or brain.
Immanuel Kant had said there could never be of a ‘Newton of a blade of grass’, seemingly rejecting the possibility of a coherent explanation of the organic world, or maybe even the impossibility of a respectable biological science. It is Darwin’s unifying contribution to our historical account of the universe that earned him the title Newton of Biology.
The end of teleology?
Many scientists and commentators assumed that Darwin’s revelation had purged biology, once and for all, of both God and teleology. Natural selection was a mindless mechanical interaction between organism and environment that could not see into the future. Birds had wings because wings and their precursors in the past had conferred a selective advantage on those creatures that possessed them. Efficient causation was a sufficient account of the circumstances under which things happen. This is a process narrative. Why should we expect more than this? Darwin gave us a process narrative of how, during evolution, bird wings arise. Why should we need to add the complication that wings arose ‘in order to’ permit flight … they arose by a series of inexorable physical processes. The ‘in-order-to’ amounts to no more than an etiology (process narrative) concerning the operation of natural selection. There is no foresight or need to infer adaptive significance. What Darwin showed was ‘how a purely causal process, blind variation and environmental ﬁltering (natural selection) can produce adaptations as biological structures with functions, i.e. purposes’ If Darwin was correct, it was argued, purpose and design in nature are only apparent purpose and design because they emerge in a naturalistic and causally transparent way. Even something as complicated as the human eye could be explained coherently in terms of a series of small evolutionary steps. Teleology, it seemed, could now be removed from mainstream biology, and returned to its rightful owners … intentional agents like humans and God.
Even Darwin’s close friend and advocate Thomas Huxley, in a review of On the Origin . . . written for the London Times newspaper on Dec. 26 1859 declared that Darwin had freed the world of ‘… the snares of those fascinating but barren virgins, the Final Causes …’
Another of Darwin’s contemporaries, Karl Marx (1818-1883), wrote in a letter to Friedrich Engels that teleology had been dealt a ‘death blow‘ and that ‘The rational meaning of teleology is empirically explained by natural selection’.
Marx, like many others up to and including the present day, assumed that teleology had been put to rest when just the reverse had happened. Darwin had explained how the manifest designed wonder of the natural world had arisen out of an ignorant mechanical process. Natural selection itself is mindless, unintelligent, and without foresight … it cannot possibly have purposes and goals. However, the products of natural selection clearly have both purpose and design, even though they lack awareness of both. Natural selection is ‘for without foresight‘ (my contribution to the popular alliteration that litters this topic). Darwin had not explained teleology and design away: by providing a naturalistic explanation for their presence he had given them scientific legitimacy and made teleology honest. True, he had removed the ‘intelligent’ from ‘intelligent design’ but he had left the ‘design’ intact. The shocking reality, so difficult for people to accept, was that the entire designed community of life had been ‘created’ by a non-intelligent process.
The difficult intellectual step here is the acknowledgement that reasons and purposes can exist independently of reasoners. Humans do not put reasons, purpose, and design into nature, but they are the only organism that is aware of them. There are reasons why the Earth orbits the Sun, the spider builds a web, the grass is green, and I have a headache – even though the Earth, the spider, the grass and I are unaware of these reasons.
The single major objection to teleology is that nature cannot have reasons or purposes: only humans can have reasons or purposes because only humans are capable of conscious deliberation. A spider’s web cannot manifest purpose or design because spiders do not have human-like intentions. There is a subtle distinction here. We are in error when we associate web-building with spider foresight but, importantly, we are also in error when, as a corollary, we also deny a connection between web-building and catching flies. We make the mistake of assuming that only foresight can provide a reason or purpose for web-building.
Reasons were present in the universe long before humans existed. The organic world is saturated with reasons, but only humans can represent these reasons. Philosopher Dan Dennett has expressed this eloquently by pointing out that organisms are ‘competent without comprehension‘ and ‘reasons do not require reason-representers‘ … ‘humans are the only reason-representers‘.
By providing an explanation for teleology Darwin had not explained it away, he had simply grounded it in natural selection. He demonstrated how, in living organisms, organic change is purposive because it creates beneficial functional adaptations – and it does so without consciousness, foresight, intelligence, or deliberation.
Principle 1 – Reasons and functions can exist independently of reasoners
Natural selection is ‘for without foresight’ (my contribution to the collection of nifty expressions!).
Principle 2 – Humans are the only reason-representers
The problem of teleology rapidly becomes mired in the semantic nuances of words like ’cause’, ‘reason’, ‘purpose’, ‘selection’, ‘adaptation’, ‘function’, and ‘design’. With natural selection Darwin bequeathed us a can of scientific, philosophical, and linguistic worms. Is the chatter about teleology just a tedious grand-scale argument about semantics? Well, yes … but remember, what we are trying to do here is separate the real from the imagined.
The semantic range of the word ‘reason’ is very broad and seemingly associated with that of the word ’cause’. In everyday language the word ‘purpose’ is broadly defined as the reason why something is done or why it exists, and we tend to use it in relation to reasons that are conscious human intentions. The products of evolution are confusing because they seem to demonstrate purposes in the absence of intentions and language stumbles in its attempt to represent this state of affairs.
As scientists should we be advocates of purpose in nature or should we try to get rid of it by becoming teleological eliminativists?
This raises the question as to whether the idea of purpose has any constructive role to play in biology. Perhaps science would be better served if it insisted that nature and organisms do not have any purposes, only humans have purposes – that in science the word ‘purpose’ and the implication of purpose should be restricted to those circumstances where an intelligent agent is at work.
From the days of the Scientific Revolution many scientists and philosophers have insisted that the word ‘purpose’ be used restrictively, applying only to human conscious intentions, thus purging nature of purpose. Under this semantic regime purpose in nature becomes a creation of the human mind.
If teleological language is non-scientific and superfluous, a projection of human thinking onto nature, then wouldn’t it be best to remove it altogether? Perhaps it can be replaced by the language of functional analysis. By changing statements about ‘what something is for‘ with statements about ‘what something does‘ or ‘how something works‘ the purposive aspect can be eliminated and forgotten. Isn’t it simpler and more scientifically acceptable to use a ‘process narrative’ by stating the fact that ‘The heart pumps blood‘ rather than adding complexity and teleological confusion by saying ‘The heart is for pumping blood’?
Philosophers, believing they are providing a service to biologists by purging purpose from biological language, have concentrated on the ideas of ‘function’ and ‘adaptationism’ and ways of rendering them impotent of purpose. This has led to an elaborate philosophical industry that explores such things as Selected Effects Theory, Generalized Selected Effects Theory, Etiological Theories, Causal Role Theory, Neo-Teleology and more. But functional statements so important in all biology are critical in subjects like evolutionary biology, anatomy, developmental biology, molecular biology, physiology and much more. If, as is claimed here, purpose in biology is real, then trying to exorcise teleological language is a vain enterprise.
When we replace teleological language with purely descriptive language something is lost, the meaning is distorted, and the wonder of nature is diminished. If we replace ‘Flowers are coloured in order to attract bees’ with ‘Flowers are coloured and attract bees’ we find that the implied constraining aspect of adaptation as a consequence of ‘self-correction’ has been lost. Flower colour has not arisen in a chaotic way, it is not arbitrary, just happening to exist, it arose by a process of selection – albeit unconscious selection – governed by an evolved program, the genetic code. Many biologists continue to use teleological language while resisting teleology. Once we accept the use of purpose-talk in biology such philosophical mental contortions become of academic interest only.
Hard-nosed scientists have tried to avoid the real purposive character of living systems by resorting to what amounts to demeaning euphemism, using terms like: ‘neo-purpose’, ‘apparent purpose’, ‘goal-directed systems’, ‘hierarchically organised self-regulating systems’, ‘cybernetic systems with feedback’, ‘archaeo-purpose'(Richard Dawkins), and ‘designoid'(Richard Dawkins). The word ‘teleonomy’ was introduced in 1958 by Colin Pittendrigh (a British-American biologist best known for his study of biological clocks) to draw attention to non-conscious goal-directed activity. Biologist Ernst Mayr pointed out that the ‘in order to’ of biological systems is not the consequence of mental intention but evolutionary function, suggesting the term ‘teleonomic’ be restricted to systems operating on the basis of a program of coded information. The list goes on.
Certainly a distinction may be made between purpose as conscious intention on the one hand, and a sort of pre-conscious purpose (yet another term, this time invented by me) which is purpose that has arisen as a consequence of natural selection. But this distinction only draws attention to the fact that consciousness itself is only made possible by the mindless purposiveness of natural selection. Teleology did not arrive on Earth abruptly with the human intellect. Human intention is itself simply a highly developed aspect of the telos that pervades all nature; the mind is telos that has become self-conscious. Life and subjectivity ‘bubbled up from the bottom, not trickled down from the top‘ (Dan Dennett) a point emphasized by the claim that ‘evolution is cleverer than you are‘. Human subjectivity does not account for or validate natural processes, natural processes account for subjectivity: ‘Human consciousness is an effect, not a cause‘. Again, in the Laws (10.903c) Plato declares ‘you perverse fellow … you forget that creation is not for your sake; rather you exist for the sake of the universe‘ drawing attention to the fact that we are a part of the universe not apart from it.
Deference to consciousness probably comes in part from the belief that everything in nature is a product of ignorant deterministic necessity while consciousness can make choices, can exert free will. But the relationship between free will and determinism is a complicated and contentious philosophical matter. Can we say that the artificial selection of plants and animals based on human environmental factors is purposeful but the natural selection of plants and animals according to non-anthropogenic environmental factors is not? Does a prosthetic leg have a purpose because it is a consequence of human deliberation, while speaking of the purpose of an actual leg is resorting to metaphor?
Biological explanations will remain teleological because so many of them are about reverse-engineering as we try to work backwards from functional explanations based on a process of selection. Talk of functions and functional analysis entails consideration of both future effects (teleology) and the evolutionary path of natural selection that gave rise to them (etiology). It is much easier to explain (teleologically) that a spider’s web is to catch flies than to recount the etiology of web-building. Yes, teleological explanations are ‘closer to us’ as shorthand accounts that save us the protracted process of enumerating the conditionally necessary antecedents required for a satisfactory causal explanation. But just because many organisms lack foresight and hindsight does not mean that they also lack reasons and purposes.
The problem of metaphor
For Aristotle telos was an inner principle of change that did not necessitate the use of anthropomorphic metaphorical language. However, there is no doubt that suspicion about teleology is encouraged by clumsy metaphorical language – the times when we use consciousness-talk in a careless way in relation to non-conscious nature.
When we say that a particular trait is ‘favoured’ by natural selection we are using the language usually reserved for conscious minds in relation to a non-conscious process. Clearly this is the metaphorical ‘as if’ language of human psychological states used in a lazy and mistaken way when applied to nature. If this is what we understand by teleology then clearly such usage can be usefully excised from scientific discourse.
But other cases are not so straightforward: they are a matter of interpretation, of polysemy, in a world where none of us is semantically omniscient. All we can do is state our case and assert what we think is real. So, for example, when we say ‘Spiders build webs to catch flies‘, there are at least three ways that this may be interpreted:
We are implying (reading into the meaning of the sentence) anthropomorphic metaphor, in a similar manner to Case 1, such that spiders have human-like conscious intentions and can anticipate the future. This is not, however, a necessary interpretation.
We are implying that spiders have been created by an intelligent agent of some kind, that agent having purposes in mind. This is extrinsic teleology, the purposes we see in organisms have been imposed externally in the same way that a watchmaker imposes purpose on a watch.
If these cases are comprehensive then by denying external agency and anthropomorphic metaphor it might be assumed that teleological language serves no useful function and can therefore be ignored.
Sources of order and purpose 6 – Teleological eliminativism.
Natural teleology (purpose-talk in biology) is metaphor – it is empty, having no referent in reality, and as such it is both unscientific and unnecessary
Presumably these are the kinds of teleology Professor of Philosophy at Florida State University Michael Ruse had in mind when he pointed out in his book Darwin and Design: Does Evolution have a Purpose? (2003) that when we ask ‘What are eyes for?’ and ‘Is eyesight good?’ we are using ‘as if’ language: we are looking for goals in things that do not and cannot have goals (they are not conscious).
Darwin no doubt struggled to find the appropriate words to describe his radical process that was so similar to human choice and the artificial selection whose products were the outcome of human intention. I have used the inadequate human metaphor of ‘self-correction’. Darwin used the human-intention-sounding word ‘selection’, softening its implicit subjectivity by employing the adjective ‘natural’.
Ruse acknowledges the difficulty of removing metaphor from biological language – that a doctor is being teleological when she tells a patient that he is anaemic, and that it is teleological to claim that bodies sweat and shiver to regulate body temperature. He states that purpose-like phenomena like these are ‘not there in reality’ but he recommends we continue using purpose-talk because it is ‘just part of the way in which we map reality in order to make sense of it’. In biology we are simply incapable of giving ‘an unvarnished report on reality’. The design and purpose metaphor is appropriate and fruitful because it gives us a ‘forward-looking kind of understanding’. And in his ‘On Purpose‘ (2018) ‘. . . something we might use to understand the world but in no sense constitutive of the world‘. He expresses sentiments similar to those of physicist J.B.S. Haldane who declared that teleology is like a mistress ‘ . . . we cannot do without her, but cannot afford to be seen with her in public’. Ruse is not proposing teleological eliminativism (get rid of teleology), more a kind of teleological fictionalism (teleology is a useful fiction, a valuable heuristic device). On this view teleological language is a kind of shorthand that saves the tedious work of describing the developmental history of adaptations.
Professor Ruse keeps good company as he is also following in the steps of Immanuel Kant who addresses teleology in his third critique (1790), the ‘Critique of teleological judgment‘ in which he defines natural teleology as occurring when the parts of wholes are reciprocally both means and ends. Kant concludes that teleological language cannot be avoided. His argument is difficult to follow but it seems that though the design in nature implies a supernatural designer, such matters are beyond our science since faith is not knowledge, and Newtonian physics has no truck with final causes, so talk about purpose in nature can only ever be ‘as if’ talk. Ruse neatly summarizes the state of play. Both Plato and Aristotle saw design and purpose in the world, Kant saw them as human projection. ‘Plato: God put purpose into the world – external teleology. Aristotle: purpose is part of the fabric of the world – internal teleology. Kant: purpose is heuristic, needed to do science but in itself of no ontological content – mind-given teleology‘.
Sources of order and purpose 7 – Teleological fictionalism.
Purpose-talk is a convenient explanatory tool or heuristic device, but it is only metaphor: it has no basis in reality
Based on all these cases we have, at best, only apparent purpose and apparent design because purpose and design, if not inculcated in the world by supernatural agency, are our mental creations as anthropomorphic metaphor: they are only real in the human mind.
What then, if these interpretations are accepted, would be a rightful way of thinking about purpose and design in biology?
Well, the purpose we ascribe to a chair as an object for sitting on is in our minds, not in the chair itself. The chair ‘just is’. So we must approach biology in the same way. The purposes we see in nature are purposes added by our minds so when we say that nature demonstrates design and purpose in its adaptations it is only ‘as if’ this were so. In reality nature also ‘just is’. As a product of a mindless mechanical process it is equivalent to mountains, the wind, and the sea.
But clearly we cannot say that nature ‘just is’ in the same way that a chair ‘just is’. Aristotle’s writings show that he would agree that the purpose of a chair comes from the human mind not the chair. He would also agree that nature does not have conscious intentions, and that its telos has not been instilled by an intelligent agent. None of the above cases remove the self-evident goals we see in all aspects of nature itself.
This brings us to the fourth interpretation and the crucial point in the debate about teleology.
On the one hand teleology must be mistaken because natural selection cannot possibly have ‘aims’, ‘goals’, or ‘ends’ – only a consciousness capable of deliberation has foresight like this. All such language is therefore ‘as if’ language, it is metaphor. And since metaphor is not real then teleology is not real: it is only as if there are goals, purposes, and design.
On the other hand the products of natural selection are self-evidently purposeful, and not in a slight or incidental way. Not only does nature ‘do nothing in vain’ – it created the human brain. Natural selection is ‘cleverer than you are’.
How do we reconcile these two perspectives?
Close inspection of these claims reveals that the factor determining the reality of teleology is conscious deliberation. Without conscious deliberation there can be no purpose or design. And yet we know that nature is saturated with purpose and design, so what is going on?
The answer is simple but difficult to grasp because of our traditional ideas and our habits of language. We assume that intricate design must be the consequence of intellect. There is indeed both purpose and design in nature but it arose by means of mindless natural selection. This is the reality in nature: purpose and design emerged from an ignorant process. The subjectivity we frequently associate with words like ‘purpose’ and ‘design’ is part of a semantics that is yet to catch up with this metaphysics.
This then is the interpretation adopted here.
We are implying that spider webs are the product of a mindless process, natural selection, whose products (as appraised by conscious human hindsight, foresight, and reason) demonstrate both purpose and design.
The argument developed here is that the goals of nature are not conscious goals … but they are goals nevertheless, and they exist independently of human minds. We are in error when we associate web-building with spider foresight or intelligent design but, importantly, we are also in error when, as a corollary, we also deny a connection between web-building and catching flies. We make the mistake of assuming that only foresight, our minds, can provide a reason or purpose for web-building. We can understand the way that natural selection operates in a purposeful selective way though its products (except humans) are oblivious to this fact.
Mainstream science today still rejects the reality of purpose in nature because of the occasional blatant metaphor and the concern that teleology entails either an ackowledgement of divine intervention or the insertion of human subjectivity. This apparantly trivial quibble has substantial consequences for metaphysics, our scientific perception of reality. Cases 1 to 3 suggest that organisms, their structures and functions, ‘just are’, in the same way that chairs in reality ‘just are’: to attribute purpose and design to nature is, at heart, an error because they are not ‘real‘, they are simply metaphor.
But the mode of existence of a living organism is very different from the mode of existence of a chair. We are, after all, much more like monkeys, or even trees, than we are like rocks. When we say ‘The eye is for seeing‘ we are acknowledging that the existence of the eye is a consequence of a selection process. Where there is selection, there is selection ‘for‘. And in nature where there is an aim, a ‘for’, and as there is a beneficiary there is also a purpose.
Darwin demonstrated that selection in nature does not require intelligence because it is ‘natural selection‘. The absence of conscious goals does not mean that teleology is a fiction. As an ignorant and mindless processs natural selection can easily be dismissed as inconsequential, not real, but among its products are both the human body and the intelligent conscious human mind. Natural selection itself may be purposeless but its products are not. The purposes of organisms existed in nature long before they were represented in human minds, and they are not apparent, they are real. Evolution ‘is cleverer than you are‘.
Aristotle would point out that teleology is the actualization of the pre-existing potential for form (today we would refer to this as the informtion contained in DNA) operating through conditional necessity to produce the physical structures and functions necessary for existence.
Aristotle & Darwin
Darwin once wrote to a friend that ‘Linnaeus and Cuvier have been my two gods, though in very different ways; but they were mere schoolboys to old Aristotle’.
Aristotle and Darwin were, in terms of their theoretical impact, the world’s greatest ever biologists, and they had much in common. Aristotle’s biographer Armand Leroi tells us they were both sons of physicians who escaped their fathers’ occupations by retreating into nature. They reaped the benefits of being both generalists and specialists at the same time, becoming familiar with the natural world in both its wide grandeur and dissected detail. Aristotle created biology (if not science itself) from scratch, and Darwin transformed our understanding of the living world and its history. Both agreed that the functional design we see in living organisms does not necessitate either theism, mystical vitalistic forces, or intelligence.
Aristotle was a deist who resisted organized theism and was adamant that telos had nothing to do with human deliberation. He did not have a coherent concept of evolution (this was irrelevant to his account of natural teleology) although there were vague notions of selection in nature, even in his day. In noting that ‘Nature makes nothing in vain but always as far as possible for the best in respect to each kind of living thing’ (IA 704b15-18) he had, to all intents and purposes, described what today we would call functional adaptation. He also insisted that the goal-directedness that existed in organisms was not a response to a causal pull from the future, but a necessary application of explanatory over causal priority. His natural teleology claimed that like begets like for intrinsic reasons – the source of purpose in any organism stems from its inner nature.
Darwin then explained how functional adaptation was a consequence of many generations of mindless mechanistic interaction between organism and environment combined with differential reproduction. Natural selection was an account of the way that variation was ‘selected’, and therefore selected ‘for’, but it did not account for the variation itself. Darwin emphasised the long-term interaction of intrinsic (we would say genetic) factors and extrinsic (environmental) factors. In 1868 Darwin wrote ‘The whole subject of inheritance is wonderful‘. But neither man provided an answer to what became known as the ‘riddle of heredity’: that would have to wait until the genetic revolution in the 20th century culminating in the deciphering of the genetic code in 1952.
Darwin had ambiguous feelings about teleology, making various references to final causes but regarding the question of design as ‘insoluble‘. In 1874 he concluded a debate with American Christian botanist Asa Gray about design in nature by agreeing that his evolutionary theory reinforced teleology. ‘What you say about teleology pleases me especially, and I do not think any one else has ever noticed the point. I have always said you were the man to hit the nail on the head.‘ He also wrote to his lawyer friend Thomas Farrer ‘(I)f we consider the whole universe, the mind refuses to look at it as the outcome of chance – that is, without design or purpose. The whole question seems to me insoluble, ….‘
Paradoxically Darwin could not concede the Aristotelian goal-directed purposiveness of nature even though he had provided compelling evidence of the way it had arisen. Purpose and design in Darwin’s day was evidence for God – and that the agnostic Darwin could not countenance.
Aristotle is often regarded as the source of biological essentialism whereby kinds of things have uniquely shared essences that define what it is for them ‘to be’ – akin to the way that species created by God are unique and immutable. These species were referred to as natural kinds. Transitional forms were impossible: any variation would have to be aberrant or accidental. Essentialism is a complex notion with various interpretations but when Darwin insisted on the importance of variation much of essentialism was abandoned.
Aristotle pointed out that the purposiveness manifest by living organisms arises from their inner nature; Darwin explained how that purposive inner natures arise out of the long-term mindless process of natural selection; then in the 20th century came explanations of the molecular source of this purposiveness as information carried from generation to generation in the genetic code; we await a fuller account of ‘information’.
The argument developed in this article is that purpose and design in nature are a fact of the world, not a creation of our minds. Human art is often treated as the paradigm of design yet how much more complex and intricate are the integrated functional designs we see in natural systems? A process that can produce something as purposeful and intricately designed as the human brain ‘is cleverer than you are‘. The human body and brain are far more sophisticated in functional design than anything ever produced by humans – and they are generated by a mindless process that is unaware of itself and its creations, natural selection.
Our foray into teleology has revealed some of its many and protean faces. In the final analysis we have to decide which of the many applications of the word ‘teleology’ is most appropriate for science. Eight of the most popular candidates have been discussed here: theism, vitalism, chance, necessity, natural teleology, natural selection, teleological eliminativism, and teleological fictionalism. It is suggested that biologists follow the path of their mentors Aristotle and Darwin who each made major contributions to todays scientific understanding of purpose and design in nature.
Deterministic regularities give the universe its order and design. After two millennia, following the analytic path of investigation promoted by the naturalistic pre-Socratics, Aristotle, and the empiricists of the Scientific Revolution, we now understand these regularities much better than Aristotle could possibly have imagined (although we do not know why they are as they are). We could amaze him with a present-day explanation of why, to use his own words, ‘stars do not have feet’. The existence of non-conscious constraining physical laws in the universe means that ‘not just anything can happen’ and that outcomes or ends become more or less predictable and knowable.
Nature clearly designs things, but of course it does not design with intention as we humans do. We see purpose in all aspects of nature, but it is not the conscious purpose of human deliberation. So, is nature’s design and purpose only apparent purpose and design? Do animals and plants have no more real purpose than a chair or the moon? The complex information transmitted between generations of organisms in the molecules of DNA would suggest otherwise.
Aristotle recognised the order manifest in inanimate nature but also the additional unique kind of order we see in living nature which has both aims and beneficiaries who are unaware of the benefits they receive. This has nothing to do with metaphorical language and human interpretation, it is present in nature itself. This is why he declared as absurd the idea that nature’s order was a product of the deliberating mind. Darwin was, of course, a modern who had no time for theism or vitalism even though he often described the operations of nature using the language of metaphorical human intention, words like ‘design’, ‘adaptation’, ‘selection’, ‘function’, and ‘purpose’.
The human mind has foresight, when most organisms do not. But absence of foresight does not equate to absence of purpose. Natural selection is an ordering process (a sorting algorithm) that occurs between living organisms and their environments that results in physical changes (adaptations) that our future-oriented minds can understand as beneficial or, as Aristotle said, ‘for the better’. The observation that ‘the purpose of an acorn is to become an oak‘ is not equivalent to the observation that ‘the purpose of a falling apple is to hit the ground’. Apples, when they fall, do not do so in an arbitrary way, they do so in a way that is constrained by the laws of physics. But organisms are, in addition, products of natural selection and therefore display the purpose that has been inserted by the unconscious process of selection ‘for’ something.
Darwinism did not discredit teleology. It is a supreme irony that the expression ‘natural selection’ (which Darwin the atheist-agnostic used to name the process that would transform our understanding of the world) contained within it the very teleology he found ‘insoluble’. In order to express the essence of evolution Darwin the biologist, like biologists today, resorted to language reminiscent of conscious intention. ‘Selection’ is the metaphorical language of conscious choice. And yet by the addition of the adjective ‘natural’ Darwin had, we now realize, successfully isolated the unconscious purpose exhibited by organisms themselves. Darwin had expelled intelligence from ‘intelligent design’ but the design remained. He had given a naturalistic account of the way that natural teleology had arisen.
Neither Aristotle nor Darwin had a scientifically adequate account of heredity but this did not weaken their cases. Biological purpose arises as a consequence of the interaction between organisms and their environments over many generations, it is unrelated to human foresight or hindsight and it does not need to be described solely in terms of its underlying matter. We do not need a new word ‘teleonomy’ to simply recapitulate what Aristotle was at pains to assert himself and the fact that design and reasons emerged from matter in a deterministic way as described by Darwin has no bearing on this.
‘Evolution is cleverer than you are’
Orgel’s Second Rule (1985) – from a citation attributed to Francis Crick and promoted by philosopher Dan Dennett
The two articles above have investigated the idea of teleology as it is expressed in the works of Aristotle and Darwin. Aristotle had no doubt that purpose in nature was real, it existed within nature itself: it was not a creation of God, and it was not inserted by the human mind as metaphor or some other mental convenience. The beneficial effects we see in nature did not arise by either chance or necessity, but by design. Darwin realized that to ascribe purpose to nature might, in the popular mind, imply the activity of god. He therefore remained uncommitted in his public views on the matter while his work, in fact, provided the physical mechanism that was lacking in Aristotle’s purpose.
In examining the work of these two men I have mounted a 21st century defense of Aristotle’s natural teleology as bio-teleological realism, the claim that there are mind-independent purposes in nature.
Our ancient ancestors believed that the world was imbued with spirit, while ancient, medieval, and modern theists believed that God(s) was present in all things (omniscient, omnipotent, omnibenevolent, and omnipresent). The world was interpreted in human terms: it was personified and anthropomorphized. For Plato, the order we see in the world was superimposed extrinsically on everything by the Demiurge. In contrast Aristotle’s emphasis was more on the physical world itself and especially that of living organisms and the internal formal cause that ensured that like begets like. For him, the function and design so evident in all organisms emanated from within them as potential to be actualized in the future. This was intrinsic goal-directedness.
Aristotle’s natural teleology did not imply backward causation: it was not anthropomorphic or theistic, nor was it a mere explanatory tool used to back up materialist-mechanist causal explanations. His telos was not conscious planning, and intention, more to do with the culminations of processes that follow a predictable path. Final causes ‘ . . . function quite literally as the direction-givers and the ends and limits of developments necessitated by formal-efficient and material-efficient causation . . . This does not mean that final causes have only a heuristic value . . . in demonstrations of the teleological type the final causes are part of the conclusion that is being demonstrated, the practice of Aristotle’s natural science demonstrates the very existence of natural teleology.’
In the Christian Middle Ages intellectual life was strongly focused on final causes or purposes, about why things occurred (usually a metaphysical or religious question) rather than how they occurred (an empirical or scientific question). Medieval Scholastics blended Platonism with Aristotelianism and Christian theology. Aristotle (known as ‘The Philosopher’) was studied by Thomas Aquinas when theology was preoccupied with the end of things (known as eschatology) which entailed close analysis and interpretation of the biblical text – mostly the Book of Revelations – in a discussion of the afterlife, heaven and hell, the second coming of Jesus, resurrection of the dead, the last judgment, the world to come, and much more. Here was Christian teleology as an answer to the question ‘How will it all end?’ and it presented Christians with the powerful imagery of the Armageddon or Apocalypse as the final mighty clash between the armies of good and evil at the Omega point, the end of time. Christianity speaks of temporal boundaries … and, needless to say, all this is a long way from Aristotle’s telos. Even so, Medieval Thomist Scholastics united Christian theology with both the extrinsic Platonic idea of a transcendental Demiurge, the intrinsic teleology of Aristotle, and the Islamic theology of Avicenna and Averroes. All was united in God’s divine plan for his Creation.
In the Early Modern period (c. 1550-1750) teleology was at the heart of a growing intellectual divide as the Western world began its move from a religious to a scientific grand narrative. Eager 16th century mechanistic scientists wanted to shake off the traditional deference to the classical intellect, religion and the Bible by beginning the naturalistic experience anew. Aristotle was an ancient and increasingly irrelevant figure to be torn down as part of the process of starting afresh. With the advent of a more mechanistic, materialistic, and experimental science and the criticism of powerful intellectuals like Francis Bacon (1561-1623), Robert Boyle (1627-1691), Rene Descartes (1596-1650), Thomas Hobbes (1588-1679), and later John Locke (1632-1704) and Baruch Spinoza (1632-1677), formal and final cause fell out of favour. Treatment of nature in anthropic terms – endowing trees, mountains, animals, plants, with intelligence or supernatural agency was frowned on, although divine teleology was still in evidence. All-in-all the Scientific Revolution over-extended its antipathy to non-human agency by exorcising purpose (teleology) from living organisms altogether. And in so doing living organisms, lacking conscious deliberation, took on the character and purposelessness of inert matter. The living was subsumed to physics and chemistry.
Aristotle had made blatant mistakes: he propounded a theory of spontaneous generation, promoted a strongly hierarchical view of the world as a scala naturae, misinterpreted the heavens, treated the heart as the seat of intelligence, motion, and sensations, and much more that appears ludicrous today. He had depended too heavily on deductive logic rather than experiment and observation, even though his dissection of organisms and concern for sound procedural principles demonstrated an acute analytic scientific awareness. Leroi suggests that Aristotle ‘invented science from scratch‘. but, even as the world’s greatest ever polymath he would, in the fullness of time, inevitably be surpassed by those who stood on his shoulders.
Science continued its investigation of order and pattern in the universe and for most people, scientists included, the design evident in nature still pointed directly to God. The influential 19th century English clergyman William Paley expressed the general view of his day in the book Natural Theology (1802) which asserted that the obvious design we see in the natural world was irrefutable evidence for the hand of God. Just as we attribute the order and purpose of a watch to the watchmaker, so the design and purpose we see in nature was a consequence of the divine Maker of the cosmos.
Then in 1859 Darwin’s theory of natural selection provided a naturalistic answer to questions like ‘Why do birds have wings?’ Birds had wings because the historical development of wings had conferred a selective advantage on those creatures that possessed them. Like Aristotle’s natural teleology, Darwin’s natural selection did not invoke either theism, vitalism, or anthropomorphism even if he, and later scientists, continued to use anthropocentric language. Aristotle’s ‘inner principle of change’ sounded to many scientists like vitalism, or theism, or both. Darwin had, it was believed, drawn both Creationism and teleology to a close. The ‘survival of the fittest’ was an expression coined by social Darwinist Herbert Spencer in his Principles of Biology (1864), his pithy summary of Darwinian theory. Alfred Russell Wallace suggested to Darwin that Spencer’s phrase was preferable to Darwin’s own choice of the words ‘natural selection’ to summarize his grand theory. Wallace considered it imprudent to imply that nature can engage in conscious choice. Darwin did not accept Wallace’s suggestion outright, but he did acknowledge the pervasive use of metaphor in describing nature and, eventually, Spencer’s words appeared in the fifth edition of On the Origin . . . which was published in 1869. On p. 72. he states, ‘I have called this principle, by which each slight variation, if useful, is preserved, by the term Natural Selection, to mark its relation to man’s power of selection. But the expression often used by Mr. Herbert Spencer of the ‘Survival of the Fittest’ is more accurate, and is sometimes equally convenient.’ Though perhaps more palatable, Spencer’s words had their own problem, needing a reference to heritability if tautology was to be avoided.
Evolution is now universally accepted within the scientific community but teleology, so full of metaphorical language and religious associations, is generally regarded as an ancient and outmoded idea promulgated by the mistaken Aristotle. Teleological language may have some explanatory value but teleology itself has no foundation in the real world and is therefore of little consequence for modern science. However, it is argued in this article that Baconians of the Scientific Revolution, in their desire for a fresh start, had over-reacted to religion and the ancient anthropomorphization of nature. This has remained with us. Darwin did not explain teleology and design away: he gave them scientific credibility.
Aristotle summarized his work in biology by using an uncharacteristically mystical and poetic phrase. From 2000 years ago he passed to us the message that all living things ‘partake in the eternal and divine‘. Darwin would never have made such a statement. We are tempted to smile and allow Aristotle a momentary and moving literary flourish, but this would be a mistake. His scientific investigations began with the examination of change and the paradox of permanence in change. One pillar of his teleology was the observation that though individuals perish, their form persists from generation to generation … what today we might call the immortality of our genes. To the Greek mind, and ours, immortality was equated with the divine. The most natural function of living things is to produce others like themselves – and in so doing they are immortal, participating in the eternal and divine. Nothing that is perishable is able to ‘remain the same and one in number’ but through reproduction it ‘remains not the same, but like the same, not one in number but one in form.’ (Anima II, 415a23-b7).
In sum, the intricate design and purpose we see in nature is self-evident, greatly surpassing any human attempts at design. If this design is not imposed from outside by some intelligent or vital force – and not mapped onto the world in some way by the human mind, then it must have arisen from within nature itself. Species-specific designs are repeated from generation to generation again and again in a path-dependent way. Design in nature produces functional adaptations that are (‘for the good’ or ‘for the better’) and goals or ends with beneficiaries are acceptably referred to as purposes. None of this entails the supernatural or mind-dependent metaphor. All of this was well known and clearly stated by Aristotle who called it telos . . . but 2000 years would pass before Darwin eventually provided a scientific account of the origin of this intrinsic goal-directedness. Our confusion arises from what philosopher Dan Dennett has called Darwin’s ‘strange inversion of reasoning‘, our refusal to accept that natural selection is ‘for without foresight‘ (me) producing organic wholes that are ‘competent without comprehension‘ (Dennett) . . . that purpose ‘bubbles up from the bottom, not trickles down from the top‘ (Dennett).
When Richard Dawkins states that biology is ‘The study of complicated things that give the appearance of being designed for a purpose’ he is making a statement that uncompromisingly links ‘purpose’ to ‘conscious intention’. In doing this he ignores the way teleology is firmly embedded in biological discourse and joins those who consider the investigation of function in biology as a matter of heuristic convenience. In so doing he restricts the word ‘purpose’ to human intention, downplaying the miraculous purposive achievements of natural selection – which include the human body and brain. In a bid to exorcise from biology any hint of the Argument from Design he has thrown the baby out with the bathwater.
Because we are mostly familiar with design and purpose as a consequence of human planning (which includes hindsight and foresight) this does not mean that purpose in nature cannot be real. Limiting purpose-talk to situations involving human subjectivity renders natural teleology, by definition, a human construct. This article has argued that teleology did not arrive on earth abruptly with the human intellect and that purpose and design in nature are real; they are part of the fabric of the natural world, not a creation of our minds, and this is why attempts to purge biology of purpose-talk have failed. Though consciousness-talk is, sometimes, used as metaphor in biology this does not mean that there is only apparent purpose and design in nature. Design and purpose in nature are not metaphorical but literal.
To remove teleology from biology is not just the harmless elimination of metaphor, it is a reduction that diminishes our biological understanding of what exists in the texture of the world. It places living matter on a similar footing as inanimate matter in the realm of purpose, design, function, and value (making the distinction between human values on the one hand, and facts of science on the other, appear clear-cut), and diminishes the wonder of what natural selection has created.
This is not just a semantic debate concerning what we mean by the word ‘purpose’; it is a metaphysical argument about what exists in ‘reality’.
In summary: it is OK to ascribe purpose and design to nature, and to use the word ‘for’ in explaining biological function.
© Roger Spencer 19 June 2018
- The study of purpose is called teleology, and it can relate to anything
- The study of purpose in living organisms is called natural teleology or bio-teleology
- This article argues the case for bio-teleological realism – the view that purpose in nature is best regarded, not as metaphor, but as existing or imminent within living organisms themselves
- If evolution is mostly gradual change that builds on existing forms, then we might expect the ideas that represent this evolution to grade in a similar way. Purpose in nature is such an idea. Purpose emerges with the order and regularity of nature. This order has cause, and a cause is ‘for’ something. But order is not purpose in its most developed form – it is rudimentary, primordial, or archaic purpose. Adaptations of living organisms are ends that arise by design: they are ‘for the better’. Does this then count as purpose? It is argued here, with Aristotle, that absence of deliberation does not necessitate absence of purpose – that the semantic restriction of ‘purpose’ to ‘conscious purpose’ is a human arrogance that diminishes the conscious purpose that evolved out of the purpose already inherent in nature
- We are inclined to think of purpose in terms of conscious human intentions (or possibly the intentions of supernatural beings)
- There are nine major theories about natural teleology and its source: theism, vitalism, chance, necessity, Aristotle’s intrinsic natural teleology, Darwinian natural selection, teleological eliminativism, and teleological fictionalism, and bio-teleological realism
- We tend to explain biological systems more in terms of the future than we do physics or chemistry because organisms are a consequence of natural selection, selection being ‘for’ something, the ‘for’ usually entailing a beneficiary
- We accept intuitively that living organisms affirm existence over non-existence, life over death, and for this reason they have ‘interests’ or functions that make purpose-talk (like ‘plants have scent to attract pollinators’) acceptable when we would not accept a similar statement in physics or chemistry (‘the apple falls in order to hit the ground’)
- Socrates interpreted the complex and finely-tuned purposive design that is pervasive in nature as evidence for an external grand designer or God (The Argument from Design) discussed today as Intelligent Design. Plato referred to this supreme external designer as the Demiurge
- Aristotle agreed that there was purpose in nature but he thought that it derived, not from an external source, but from within living organisms themselves
- Charles Darwin’s theory of natural selection provided a coherent explanation for the diversity of organic life without recourse to external agents. His theory was revolutionary because: it removed the necessary requirement for God and a divine plan for the Creation; it implied that humans were descended from apes; it attacked the assumption of humans being at the pinnacle of life in a Great Chain of Being arranged from high to low; it suggested that the organic world had arisen in a mechanical and ‘mindless’ way
- Natural selection appeared to remove the need for either intrinsic or extrinsic teleology, teleological language being interpreted as the mistaken imposition of human conscious purpose onto the world as metaphor. Plants, for example, do not have conscious intentions. Teleology was therefore regarded as a mistaken metaphysical theory. Biologists were therefore encouraged avoid teleological language by expressing it in a non-teleological form
- In spite of Darwin’s great insight and the awareness of the pitfall of the consciousness metaphor, biologists have continued to use teleological language, noting that natural selection, though unconscious, is very like conscious-purpose-like intentionality. Various names have been suggested the most popular being ‘teleonomy’
- Though teleonomy is an unconscious process its similarity to conscious intention, the fact that it exists in nature itself and is not a product of the mind, and that it has given rise to all the complexity of biological organisation (including the brain and consciousness) warrants the use of purpose-talk which (following common usage) should be accepted as legitimate practice: it is neither metaphor not scientific error
- Today’s problem is how to express the mind-independent reality of teleonomy without using the metaphorical language of conscious intent. How can we avoid the pitfall of interpreting the error of metaphor as proof of the unreality of the phenomenon itself?
- We do not have to assume that the purpose-like character of living systems was inserted by either God or the human mind: mechanical and mindless natural selection is both necessary and sufficient. The problem is that we are constrained by language. Words like ‘design’, ‘adaptation’, even ‘selection’, and ‘purpose’ are all consciousness-talk and therefore metaphor when applied to any non-sentient object. This is not a failure of reality but a failure of language
- If teleology were just a matter of word definition and the ‘the meaning of a word is its use’ then we must accept that in both common parlance and scientific discourse ‘purpose’ is used in ways that do not entail consciousness
- Similarly the teleonomic statement that the purpose of living organisms is to ‘survive, reproduce and flourish’ should be treated as a self-evident biological axiom
- The above biological axiom also has normative weight as a statement of ultimate biological value akin to Aristotle’s final cause
- The implication of this for human ethics is discussed in the article ‘Morality and sustainability’.