…the guiding question of epistemology: the relation between thought and things, or mind and world…In the history of philosophy, this question has been posed in different ways in successive epochs. For the Pre-Socratic Parmenides it is the question of the sameness between thought and Being or between thinking and that which is. For Plato, it is the correspondence between the intellect and the forms, here knowledge of a thing is knowledge of the form of that thing. For Aquinas, it is the adaequatio between the intellect and things, where both persons and things are creatures created by God himself uncreated. For Descartes and modern philosophy, it becomes the basic question of the theory of knowledge: namely, what is the relation between a thinking self or subject and the object that appear to the subject.
The basic advance of Kant’s epistemology at the end of the eighteenth century is that it does not suppose, as is supposed by both Plato and Descartes in quite different ways, that in order for knowledge to be possible there must be a correspondence between thoughts or mental representations and things in themselves, whether the realm of forms, the metaphysical realities of the soul, God and material substance, or simply a belief in the radical independence of reality from the mind, what Wilfrid Sellars calls ‘the Myth of the Given’. After Kant, that which is true is that which is taken to be true, i.e. that which appears to a subject or self. Now, that which so appears might indeed refer to a thing in itself, but we can never be in a position to know this fact independently of how that fact appears to us. On Kant’s picture, the realm of sensibility is our access to a world that is indeed real to us, but that world is always already shot through with conceptual content, it is articulated as such through the categories of the understanding and is dependent upon the spontaneity of the subject. This is why, as Kant says, ‘the transcendental idealist is, therefore, an empirical realist’.
- Simon Critchley, Things Merely Are