Shall we finally define the free act by saying that it is not necessarily determined by its cause? But either these words lose their meaning or we understand by them that the same inner causes will not always call forth the same effects. We admit, then, that the psychic antecedents of a free act can be repeated, that freedom is displayed in a duration whose moments resemble one another, and that time is a homogeneous medium, like space. We shall thus be brought back to the idea of an equivalence between duration and its spatial symbol; and by pressing the definition of freedom which we have laid down, we shall once more get determinism out of it. To sum up; every demand for explanation in regard to freedom comes back, without our suspecting it, to the following question: "Can time be adequately represented by space?" To which we answer: Yes, if you are dealing with time flown; No, if you speak of time flowing. Now, the free act takes place in time which is flowing and not in time which has already flown. Freedom is therefore a fact, and among the facts which we observe there is none clearer. All the difficulties of the problem, and the problem itself, arise from the desire to endow duration with the same attributes as extensity, to interpret a succession by a simultaneity, and to express the idea of freedom in a language into which it is obviously untranslatable. CONCLUSION [Sidenote: Modern psychology holds hat we perceive things through forms borrowed from our own constitution.] To sum up the foregoing discussion, we shall put aside for the present Kant's terminology and also his doctrine, to which we shall return later, and we shall take the point of view of common sense. Modern psychology seems to us particularly concerned to prove that we perceive things through the medium of certain forms, borrowed from our own constitution. This tendency has become more and more marked since Kant: while the German philosopher drew a sharp line of separation between time and space, the extensive and the intensive, and, as we should say to-day, consciousness and external perception, the empirical school, carrying analysis still further, tries to reconstruct the extensive out of the intensive, space out of duration, and externality out of inner states. Physics, moreover, comes in to complete the work of psychology in this respect: it shows that, if we wish to forecast phenomena, we must make a clean sweep of the impression which they produce on consciousness and treat sensations as signs of reality, not as reality itself. [Sidenote: But are not the states of the self perceived through forms borrowed from the external world?]