David Hume (1711-1776) Portrait by Allan Ramsay 1776 Courtesy Wikimedia Commons
Though the ancient Greek philosophers placed great emphasis on the use of reason in daily life, they knew that this was not a simple matter. History shows just how difficult being reasonable has proved to be (see Reason).
Can reason alone provide motivation for action … is it reason that drives our moral behaviour or is it our moral intuitions (our beliefs and desires – our will) as Enlightenment philosopher David Hume claimed? Is an objective reason always accompanied by an intuition or are desires something that is ‘added’. Are rationally binding rules like the Categorical Imperative (behave as if to universalise your behaviour) independent of the will as Enlightenment philosopher Immanuel Kant claimed?
Is it correct that ‘appetite’ our will, passions, and desires determine the content of our attention, while reason refines it appropriately to achieve rational ends?
Questions like these are still controversial as moral philosophers, moral psychologists and others take one side or the other.
This article looks at this problem in more detail.
David Hume on reason and the passions
Scottish philosopher David Hume (1711-1776) confronted the ancient Greek problem of the divided self directly. Insofar as mental conflict entailed two entities, reason and the passions (or will), Hume pointed out that reason alone had no motivating content, motivation came from the will; it was the will that triggered action not reason. So, Hume maintained, we cannot from a particular state of affairs, make a moral judgment without input from our will, a conclusion summarised in his famous statement ‘reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them‘ this claim often further associated with his assertion about ethical propositions that ‘you cannot derive an ‘ought’ from an ‘is’‘. Following from this came his second assertion that the moral sentiments that guide our lives are not to be thought of as rational propositions but expressions of approval or disapproval, an ethical position known today as emotivism. Hume’s distinction is at the heart of lively philosophical debate concerning fact and value, science (what ‘is’) and ethics (what ‘ought’ to be). How ‘real’ is this distinction?
This matter remains unresolved as the relationship between reason and emotion/will is complex. Famously philosopher David Hume claimed that reason ‘is and should be the servant of the passions‘ (although for an account of exactly what he meant by this see Reason).
Modern moral psychologist Jonathan Haidt in the book ‘The Tail That Wags the Dog‘ points out the dominant role of emotion in our behaviour and suggests five possibly innate psychological themes around which our moral norms appear to be organised. Franz Waal in The Bonobo and the Atheist (2013) argues that we do not develop morality from de novo through rational reflection ‘we received a huge push in the rear from our background as social animals’.
Our own experience of the power of emotion over reason (like a trail of broken New Year’s resolutions) demonstrate very clearly how our behaviour is influenced by factors other than reason. Reason tends to adddress long-term consequences, while emotions tend towards short-term satisfaction. However, the relative roles of reason and passion are in principle empirical questions and we need not give up finding some kind of solution to this controversy. We all like to think we have good reason for our moral choices. But many feel moral repugnance at, among others, – incest and homosexuality – when we cannot find sound reasons for doing so, referred to in moral psychology as moral dumbfounding. People say things like ‘it just seems wrong’.
One way that reason can influence our behaviour is through the acknowledgement that our moral choices can be strongly infuenced by the situations in which we place ourselves and by a full recognition of the various ways we are subject to cognitive bias.
For the moral philosopher perhaps this is all irrelevant. If ethics is indeed about rational decisions then there is no place for moral intuitions which cannot determine what is ‘right’ or ‘good’ or what ‘ought’ to be done. Ethical propositions are fundamentally different from those of psychology or science which concern themselves with ‘is’ statements.
Behavioural science focuses on the ‘inner’ factors influencing our moral behaviour, our moral intuitions and reason. At heart behavioural science is probing our human nature to find the source of moral behaviour. Moral psychologists like Haidt maintain that most of our moral behaviour is the result of gut feelings while moral philosophers like Sidgwick maintain, on the contrary, that morality is the use of reason to manage such feelings.
What are ‘the passions’
But, recalling the problem of nature vs nurture we can recognise that morality is likely to be a relationship between factors that are working from ‘inside’ us and factors that exist ‘outside’ us. From an evolutionary point of view ‘morality’ would encourage behaviour that promotes reproductive success. Biological goals of reproductive success and general flourishing are congruent with utilitarian goals of happiness and pleasure. Morality then appears to be an interaction between our (albeit obscure) human nature and our environment mediated to a greater or lesser extent, more or less successfully, by our reason: it is one of the ways we attempt to adapt to our ‘outside’ (environment, and in this case mostly other people) in a way that will maximise our flourishing/common good/happiness/pleasure or sustainability.
Reason without passion
De Lazari-Radek & Singer suggest that moral action may be initiated by what can be called normative reasons or motivating reasons. If indeed moral action is motivated primarily by will or passion then this becomes of little interest if we wish to distinguish a rational moral action from a passionate one. An example of a normative reason would be when I decide to visit the dentist every year in March for a check-up. This decision is made in an objective way irrespective of whether I like the idea, agree with it, or desire to act in accordance with it. In contrast, after making this decision if I subsequently have a bad toothache, I have a motivating reason to go to the dentist.  Universal rules like the categorical imperative are independent of the will.
 Lazari-Radek & Singer, p. 198
De Lazari-Radek, K. & Singer, P. 2014. The Point of Vew of the Universe. Oxford University Press: Oxford