Kant's philosophical contributions and major works

Kant

Our knowledge relates to objects by means of intuition. Objects are given to us by means of sensibility, which in turn provides intuitions from which conceptions arise. The effect of an object upon representation is sensation. This sensation, brought about by the representation of the object, is empirical intuition. The object of this empirical intuition is the phenomenon, which respond to matter and form. The sensation relates to the concept of matter, while the relations under which the phenomenon functions are referred to as form. The matter of phenomena can be separated from sensation. The science of all principles of sensibility is the transcendental aesthetic.

Space is perceived as external, and time as internal.

For space to be perceived, it must have a priori representations within the mind. At its origin, space is therefore perceived by an a priori intuition in the human mind. As such, space does not represent objects as things in themselves, or in relation to each other. External intuition is used to conceive of space. This is only possible through the subjective condition of the sensibility.

Time is not empirical; like time, its representation exists as an a priori foundation. All phenomena are only possible within time. Time is by nature one-dimensional and makes linear experience possible. It is a form of sensuous intuition. Different times are simply parts of the same all-encompassing eternal time frame. The original representation of time is therefore unlimited, with quantities of time built upon this.

In the same way, the conceptions of change and motion are only possible within the representation of time. Only at different times can an object change in either form or location. Nothing can have two different forms or two different locations at the same point within time. Like space, time does not exist in isolation from the human mind. It is the subjective condition under which all intuition takes place.

Time is the form of the internal sense, the intuitions of self and the internal state. It does not determine external phenomena. Because time is an illusive phenomenon, the human conception quantifies it as a line that progresses to infinity. In other words, it is a linear conception of successive movements and changes. As such, time is the a priori formal condition of all phenomena. It exists only in relation to these phenomena. As such, all objects can only be presented under the conditions of time. Empirical reality can therefore be ascribed to time, while absolute and transcendental reality cannot be applied to it.

On the other hand, the reality of time cannot be denied: it is the conceptual form of internal human intuition. It has subjective reality in reference to internal experience. It does not in turn have objective reality. Time is the mode of representation in which the self can be presented as an object. The representation of the self in time is successive, as is the representation of all other phenomena.

The transcendental aesthetic as a whole can contain only space and time. All other conceptions of sensibility are subject to these elements. Intuition is the representation of phenomena, which exist only in space and time, which in turn exist only as a result of the human mind. The human being knows only so much as his mode of perception. Nothing beyond this can be known, experienced or investigated. Space and time are pure forms of perception, in which sensation is matter. As such, human beings can never achieve complete cognition of things in themselves, but rather, by investigating these things, an understanding is achieved of the human mode of intuition or sensibility. No synthetic cognitions is possible from conceptions or intuitions; only analytical conceptions are indeed possible in this way.

Intuition culminates in a set of relations, which translates to human perception. The same is the case with the internal intuition, because the representation of the external senses constitutes the material with which the mind is occupied. Another aspect of this reason is also that time lies at the foundation of this material, and we place our experiences and representations in time. Furthermore, time precedes the consciousness of and representations of experience. It also contains the relations of the successive, the coexistent, and the permanent.

Intuition in turn precedes the exercise of thought in relation to objects. When the intuition contains only relations, it is referred to as form, while everything represented through the medium of sense is phenomenal. It follows that the consciousness of self - also referred to as apperception - is the representation of the ego. To hold such a perception, the human consciousness must have an internal perception of previously given representations, also referred to as sensibility. Self-consciousness then produces the intuition of the self.