He makes, as did Guyau, a central point of Change, a universal becoming, and attacks the ordinary notion of time, which he regards as false because it is spatial. We ourselves live and act in _durée_, which is Bergson’s term for real time as opposed to that fictitious time of the mathematician or astronomer. He thus lays stress upon the inward life of the spirit, with its richness and novelty, its eternal becoming, its self-creation. He has his own peculiar manner of approaching our central problem, that of freedom, of which he realises the importance. For him the problem resolves itself into an application of his doctrine of _la durée_, to which we shall turn in due course. Bergson insists with Guyau and Blondel upon the primary significance of action. The importance attached to action colours his whole theory of knowledge. His epistemology rests upon the thesis that “the brain is an instrument of action and not of representation,” and that “in the study of the problems of perception the starting- point should be action and not sensation.” This is a psychology far different from that of Condillac and Taine, and it is largely upon his merit as a psychologist that Bergson’s fame rests. He devoted his second work, _Matter and Memory_, to showing that memory is something other than a function of the brain. His distinction between “pure” memory and mere memorising power, which is habit, recalls the _mémoire_ of Maine de Biran and of Ravaisson upon _Habit_. Bergson sees in memory a manifestation of spirit, which is a fundamental reality, no mere epiphenomenon. Spirit is ever striving against matter, but in spite of this dualism which he cannot escape, he maintains that spirit is at the origin of things. This is a difficulty which is more clearly seen in his later book, _Creative Evolution_. Matter is our enemy and threatens our personality in its spiritual reality by a tendency to lead us into habit, away from life, freedom and creativeness.