The conditions of experience › Concepts, combination, and the same consciousness

Sensibility alone does not complete Kant's account. The Transcendental Logic examines thinking about objects. Its Introduction distinguishes receiving a representation from thinking the object through concepts. Neither can perform the other's task. A concept without an appropriate intuition does not yield knowledge of an object; intuition requires conceptual determination for cognition. Kant's point concerns their cooperation, not a competition to decide which faculty deserves all the credit. Transcendental Logic, Introduction I.

The pure concepts of the understanding are the categories. Kant lists twelve under the headings of quantity, quality, relation, and modality. They include unity, substance, causality, and necessity. These are not ordinary classifications such as furniture or birds. He presents them as fundamental forms for thinking an object and connects their systematic arrangement with the logical functions of judgment. Listing them, however, leaves a further task: establishing their right to apply to objects. Analytic of Concepts, table of categories.

The Transcendental Deduction addresses that right. Its second-edition argument places the unity of apperception at the center. It must be possible for the thought "I think" to accompany my representations. Kant does not mean that I constantly recite those words. The representations must be capable of belonging together in one self-consciousness. Their combination is an activity, which he calls synthesis. A mere accumulation of separately occurring representations does not by itself explain their unity as cognition of an object. Deduction, original synthetic unity of apperception.

An invented example can help. Reading successive words as one sentence requires more than noticing that separate marks appeared. The words must be combinable in a judgment with a determinate sense. This does not prove Kant's deduction: linguistic understanding is not identical to the full problem of objective experience. It illustrates why he distinguishes having representations from combining them under rules. The stronger conclusion, that his categories are necessary for objectively unified experience, requires the argument of the Deduction.

A condition of self-conscious thought also does not immediately disclose the self as an immortal substance. Kant's account of unity should not be turned into direct knowledge of a soul's nature. The wider distinction between thinking something and knowing an object constrains claims about the subject as well as claims about external things. The book later develops this restriction in its examination of the paralogisms of pure reason. Paralogisms.