The conditions of experience › Space and time as forms of sensibility

The Transcendental Aesthetic examines sensibility, our capacity to receive representations. Kant uses intuition for a representation that relates immediately to an object. The word does not mean a hunch. Human intuition is sensible: objects must be given to us, rather than produced simply by thinking their concepts. Aesthetic, introductory section.

Kant argues that space is a form of outer intuition. Representing things as outside us or beside one another already presupposes spatial relations. He therefore rejects the proposal that the representation of space is simply abstracted from previously experienced outer relations. He also argues that particular spaces are limitations within one space, rather than separate instances from which we first construct a general concept. Space is, on his account, a pure intuition. Aesthetic, Section I.

Time has a different scope. Kant calls it the form of inner sense, through which we represent our own states. Because representations of outer objects also belong to our inner life, time is a condition of all appearances, while space directly conditions outer appearances. Calling both forms of intuition should not erase that difference. A remembered worry is represented in time; it need not be assigned a spatial position in the way a cup is. Aesthetic, Section II.

This is an argument about conditions of human sensibility. It is not a report about which part of a brain processes spatial information. Nor does it suggest that space is optional or that changing your opinion can place the desk elsewhere. Kant affirms space's empirical reality for possible outer experience while denying that we can treat it as a property of things independently of our sensible conditions. Aesthetic, conclusions concerning space.