Trying to assess Kant's impact on contemporary aesthetics is by no means a straightforward task, for the simple reason that the subject is saturated with his influence. In all aspects of the theory and practice of art, it is possible to observe concepts and attitudes at work which are either a reflection of, or a response to, Kant's thinking. This might seem a rather overblown claim and a difficult one to substantiate but, without going into too much detail at this point, one has only to consider that the central tenets of both modernism and postmodernism can be traced back to Kant's Critical thought. There is the modernist's interest in the conditions of possibility of representation – as evidenced, for example, by the push towards abstraction in the visual arts and the attempt to paint not the world but the process of painting itself – and, responding to this, the postmodernist's concern that these conditions of possibility should not become universal absolutes.

The idea that respect for persons comprises the core of morality has long been associated with Kant and the ethics of the Groundwork of the Metaphysics of Morals. In particular, the second formulation of the categorical imperative (CI), the Formula of Humanity as an End-in-itself (FHE) – ‘So act that you use humanity, whether in your own person or in the person of any other, always at the same time as an end, never merely as a means’ (G, 429) – is often glossed as enjoining us to respect persons as such. On what I think may fairly be called the received view, the injunction to respect persons as such is thus, for Kant, co-extensive with morality itself.

In the preface to the second edition of his Critique of Pure Reason, Kant laments that

it still remains a scandal to philosophy and to human reason in general that the existence of things outside us … must be accepted on faith, and if anyone thinks good to doubt their existence, we are unable to counter his doubts by any satisfactory proof. (B xl n.)

The two editions of the Critique each contain a celebrated refutation of epistemological scepticisms like those of Descartes and Hume. The first edition refutation has been widely decried as relying on an objectionable sort of idealism. The refutation of the second edition, though rather more difficult to interpret than the first, has usually been read as a mere reworking of the first.

… an immense gulf is fixed between the domain of the concept of nature, the sensible, and the domain of the concept of freedom, the supersensible, so that no transition from the sensible to the supersensible (and hence by means of the theoretical use of reason) is possible, just as if they were two different worlds. (Kant, Critique of Judgment, §II, 5: 175-6)