OUTER SENSE

[B291] Outer sense is the faculty through which we intuit outer appearances (that is, as in space). In the Analogies Kant argues that to employ the understanding "in conformity with the categories"--which is to say to synthesize intuitions according to concepts in an act of judgment, to come to have experience--"we need, not merely intuitions, but intuitions that are in all cases outer intuitions". As well as being in time, Kant argues that the objective validity of the categories requires that all appearances be appearances of (empirical) objects in space; in particular, determinations of inner sense require that we represent our (empirical) selves as existing in space and undergoing "successive existence...in different states". [B293] "Similarly, it can easily be shown that the possibility of things as quantities, and therefore the objective reality of [the categories of] quantity, can be exhibited only in outer intuition, and that only through the mediation of outer intuition can it be applied also to inner sense". Helpfully, Kant "leaves to the reader to supply his own examples of this", promising that "these remarks are of great importance, not only in confirmation of our previous refutation of idealism, but even more, when we come to treat of self-knowledge".