Is the empirical thesis the one adopted? Then it is necessary to deprive the categories of all their characteristic properties. As a matter of fact they are distinguished from all other knowledge by their universality and necessity. They are the most general concepts which exist, because they are applicable to all that is real, and since they are not attached to any particular object they are independent of every particular subject; they constitute the common field where all minds meet. Further, they must meet there, for reason, which is nothing more than all the fundamental categories taken together, is invested with an authority which we could not set aside if we would. When we attempt to revolt against it, and to free ourselves from some of these essential ideas, we meet with great resistances. They do not merely depend upon us, but they impose themselves upon us. Now empirical data present characteristics which are diametrically opposed to these. A sensation or an image always relies upon a determined object, or upon a collection of objects of the same sort, and expresses the momentary condition of a particular consciousness; it is essentially individual and subjective. We therefore have considerable liberty in dealing with the representations of such an origin. It is true that when our sensations are actual, they impose themselves upon us _in fact_. But _by right_ we are free to conceive them otherwise than they really are, or to represent them to ourselves as occurring in a different order from that where they are really produced. In regard to them nothing is forced upon us except as considerations of another sort intervene. Thus we find that we have here two sorts of knowledge, which are like the two opposite poles of the intelligence. Under these conditions forcing reason back upon experience causes it to disappear, for it is equivalent to reducing the universality and necessity which characterize it to pure appearance, to an illusion which may be useful practically, but which corresponds to nothing in reality; consequently it is denying all objective reality to the logical life, whose regulation and organization is the function of the categories. Classical empiricism results in irrationalism; perhaps it would even be fitting to designate it by this latter name.