In the second place, in a duration assumed to be homogeneous, the same states could occur over again, causality would imply necessary determination, and all freedom would become incomprehensible. Such, indeed, is the result to which the Critique of Pure Reason leads. But instead of concluding from this that real duration is heterogeneous, which, by clearing up the second difficulty, would have called his attention to the first, Kant preferred to put freedom outside time and to raise an impassable barrier between the world of phenomena, which he hands over root and branch to our understanding, and the world of things in themselves, which he forbids us to enter. [Sidenote: How corrected by taking real duration into account.] But perhaps this distinction is too sharply drawn and perhaps the barrier is easier to cross than he supposed. For if perchance the moments of real duration, perceived by an attentive consciousness, permeated one another instead of lying side by side, and if these moments formed in relation to one another a heterogeneity within which the idea of necessary determination lost every shred of meaning, then the self grasped by consciousness would be a free cause, we should have absolute knowledge of ourselves, and, on the other hand, just because this absolute constantly commingles with phenomena and, while filling itself with them, permeates them, these phenomena themselves would not be as amenable as is claimed to mathematical reasoning, [Sidenote: With Kant, we assume a homogeneous space, the intuition of which is peculiar to man and prepares the way for social life.] So we have assumed the existence of a homogeneous Space and, with Kant, distinguished this space from the matter which fills it. With him we have admitted that homogeneous space is a "form of our sensibility": and we understand by this simply that other minds, e.g. those of animals, social life, although they perceive objects, do not distinguish them so clearly either from one another or from themselves. This intuition of a homogeneous medium, an intuition peculiar to man, enables us to externalize our concepts in relation to one another, reveals to us the objectivity of things, and thus, in two ways, on the one hand by getting everything ready for language, and on the other by showing us an external world, quite distinct from ourselves, in the perception of which all minds have a common share, foreshadows and prepares the way for social life. [Sidenote: But if concrete duration is heterogeneous, the relation of psychic state to act is unique and the act is rightly judged free.]