Science, Idealism, & objective reality
If we can only experience the external world of noumena indirectly as structured mental representations (Kant’s phenomena or empirical intuitions) then how is objective knowledge possible? How can we overcome the subjectivity of perception and cognition to obtain an objective view of the world? This dilemma, well known in philosophy, is called the egocentric predicament.
Transcendental Idealism and Empirical Realism
Idealist Irish Bishop Berkeley had a saying esse est percipi (to be is to be perceived) and he argued that because we can only know the world through mental representations then that is all we can know: there can be no mind-independent world. This philosophical idealism is expressed in the question ‘if a tree falls in a forest and nobody is present to hear it, does it make a sound?’ There are degrees of doubt about the external world with solipsism denying the material world altogether (only the self can be known to exist): no mind, no sound of tree falling. Against such views were the materialists and naturalism, the view that there were no supernatural forces in the world and mind is just another, albeit special for us, manifestation of physical matter. This presented another philosophical dualism, the Idealist vs the Materialist (as expressed in the witticism ‘No matter, never mind’).
Kant was no idealist in this sense: he believed that the science of his day was amassing valuable and reliable objective knowledge about the external world. Science, through its power of prediction and its technological spin-offs, had amply demonstrated its reliable link to the material world, to noumena. Kant was an empirical realist who maintained that, though we cannot know the external world directly, this does not mean that we cannot know it at all: he believed that there was an external world that could be investigated scientifically using observation and experiment and that this could uncover what he regarded as necessary truths, like Newton’s law of gravitation. In his own words, he was ‘both a transcendental idealist and an empirical realist’.
So how did Kant argue that objective knowledge was possible?
Kant could not use empirical knowledge to demonstrate the possibility of empirical knowledge, so he used what he called a ‘transcendental deduction’:
1. Only if A then B
2. B, from which we can infer . . .
(Where A = necessary conditions to have an experience B, B = experience B).
Rather than adopting a philosophical stance of skepticism and doubt, like Descartes and Hume, Kant claimed that it was beyond doubt that we obtain knowledge of the world, the important question then becomes ‘How is this possible?’
Kant asserted that it is the combined Categories of perception and cognition that make this possible. Judgements of perception (like ‘honey is sweet’) are particular and subjective but judgements of the understanding which are common to all humans, the concepts of cognition that allow us to synthesize and unify, allow us to make judgements that are both necessary and universal, that is, objective. Intersubjective agreement becomes possible even though each individual has their own ‘reality’ – the shared form of human cognition, the general human point of view, enables common (objective) understanding.
Kant distinguished between the transcendentally real (the noumenon or thing-in-itself, the ding an sich) and the transcendentally ideal (the phenomenon). He then divided the transcendentally ideal into the empirically real (like an oasis or a straight stick) and the empirically ideal (like a mirage or a stick that looks bent when placed in water). We are inclined to challenge Kant’s idea of the empirically real as being subjective, but Kant points out that though it is not possible to access the transcendentally real directly we can still make empirically real judgements. We assume that noumena are the objects of science but the objects of science e.g. atoms, species, trees, and test tubes are given to us phenomenally. Though the phenomenal world is the limit of our direct knowledge, science can assist us in an indirect understanding of the nature of phenomena, the things-in themselves. In spite of all this apparent subjectivity our cognition is grounded in empiricism – it is ‘subjectivity that works’.
This is a subtle point. For Kant our phenomenal knowledge is both transcendentally valid and objectively real. Space and time are empirically real, but they do not represent properties of things in themselves. Kant draws a further distinction between empirical objectivity and transcendental subjectivity. Space and time have empirical objectivity since they are a necessary precondition for experiencing (empirically) the world objectively: and, since they are inner Categories that are ‘given’ they have transcendental subjectivity.
Again, for Kant the external world may be a human interpretation of the world consequent on our biology, but it is not an illusion – that is abundantly clear when we bang our heads on something. He is fully aware of the move from the philosophical claim that our direct experience is only of mental appearances to the extended claim that there is no external world.
Kant believed we can only appreciate our inner sense when we also have knowledge of an outer sense. We understand that more clearly today in a more evolutionary light, as part of the evolved organism-environment continuum that allows us to persist.
Principle 5 – Reason, our understanding spectacles, allows us to move from the particular and contingent of our perception to the general and universal of our cognition. The world is given coherence by applying universal principles to particular events