Kant argues that our mathematical, physical, and quotidian knowledge of nature requires certain judgments that are “synthetic” rather than “analytic,” that is, going beyond what can be known solely in virtue of the contents of the concepts involved in them and the application of the logical principles of identity and contradiction to these concepts, and yet also knowable a priori, that is, independently of any particular experience since no particular experience could ever be sufficient to establish the universal and necessary validity of these judgments.

Kant agrees with Locke that we have no innate knowledge, that is, no knowledge of any particular propositions implanted in us by God or nature prior to the commencement of our individual experience. I2 But experience is the product both of external objects affecting our sensibility and of the operation of our cognitive faculties in response to this effect, and Kant’s claim is that we can have “pure” or a priori cognition of the contributions to experience made by the operation of these faculties themselves, rather than of the effect of external objects on us in experience. Kant divides our cognitive capacities into our receptivity to the effects of external objects acting on us and giving us sensations, through which these objects are given to us in empirical intuition, and our active faculty for relating the data of intuition by thinking them under concepts, which is called understanding, and forming judgments about them. This division is the basis for Kant’s division of the “Transcendental Doctrine of Elements” into the “Transcendental Aesthetic,” which deals with sensibility and its pure form, and the “Transcendental Logic,” which deals with the operations of the understanding and judgment as well as both the spurious and the legitimate activities of theoretical reason.

Transcendental Aesthetic#

Kant attempts to distinguish the contribution to cognition made by our receptive faculty of sensibility from that made solely by the objects that affect us, and argues that space and time are pure forms of all intuition contributed by our own faculty of sensibility, and therefore forms of which we can have a priori knowledge.

This is the basis for Kant’s resolution of the debate about space and time that had raged between the Newtonians, who held space and time to be self-subsisting entities existing independently of the objects that occupy them, and the Leibnizians, who held space and time to be systems of relations, conceptual constructs based on non-relational properties inhering in the things we think of as spatiotemporally related

Further Reading

The classical presentation of this dispute is in the correspondence between Leibniz and the Newtonian Samuel Clarke, published by Clarke in 1717 after Leibniz’s death the previous year; see H. G . Alexander, ed.,The Leibniz-Clarke Correspondence (Manchester: Manchester University Press, 1956).

Kant’s alternative to both of these positions is that space and time are neither subsistent beings nor inherent in things as they are in themselves, but are rather only forms of our sensibility, hence conditions under which objects of experience can be given at all and the fundamental principle of their representation and individuation

Kant’s thesis that space and time are pure forms of intuition leads him to the paradoxical conclusion that although space and time are empirically real, they are transcendentally ideal, and so are the objects given in them. Although the precise meaning of this claim remains subject to debate, in general terms it is the claim that it is only from the human standpoint that we can speak of space, time, and the spatiotemporality of the objects of experience, thus that we cognize these things not as they are in themselves but only as they appear under the conditions of our sensibility. This is Kant’s famous doctrine of transcendental idealism

Kant’s Transcendental Idealism#

Source

Henry E . Allison, Kant’s Transcendental Idealism, New Haven: Yale University Press, 1983 (CPR, Cambridge, p.706, Book Review)

• Transcendental idealism is a metaphysical theory that affirms the uncognizability of the “real” (things in themselves) and relegates cognition to the purely subjective realm of representations (appearances).
• The basic assumption is simply that the mind can acquire these materials only as aresult of being “affected” by things in themselves.