Bergson himself would give to his philosophy the title, The Philosophy of Change, and this for a very good reason, for the principle of Change and an insistence on its reality lies at the root of his thought.[Footnote: He suggested this as a sub-title to Dr. H. Wildon Carr for his little work Henri Bergson (People's Books). Dr. Wildon Carr's later and larger work bears this as its full title.] "We know that everything changes," we find him saying in his London lectures, "but it is mere words. From the earliest times recorded in the history of philosophy, philosophers have never stopped saying that everything changes; but, when the moment came for the practical application of this proposition, they acted as if they believed that at the bottom of things there is immobility and invariability. The greatest difficulties of philosophy are due to not taking account of the fact that Change and Movement are universal. It is not enough to say that everything changes and moves--we must believe it." [Footnote: Second of the four lectures on La Nature de l'Ame delivered at London University, Oct. 21, 1911. From report in The Times for Oct. 23, 1911, p. 4.] In order to think Change and to see it, a whole mass of prejudices must be swept aside--some artificial, the products of speculative philosophy, and others the natural product of common-sense. We tend to regard immobility as a more simple affair than movement. But what we call immobility is really composite and is merely relative, being a relation between movements. If, for example, there are two trains running in the same direction on parallel lines at exactly the same speed, opposite one another, then the passengers in each train, when observing the other train, will regard the trains as motionless. So, generally, immobility is only apparent, Change is real. We tend to be misled by language; we speak, for instance, of 'the state of things'; but what we call a state is the appearance which a change assumes in the eyes of a being who, himself, changes according to an identical or analogous rhythm. "Take, for example," says Bergson, "a summer day. We are stretched on the grass, we look around us--everything is at rest--there is absolute immobility--no change. But the grass is growing, the leaves of the trees are developing or decaying--we ourselves are growing older all the time. That which seems rest, simplicity itself, is but a composite of our ageing with the changes which takes place in the grass, in the leaves, in all that is around us. Change, then, is simple, while 'the state of things' as we call it, is composite. Every stable state is the result of the co-existence between that change and the change of the person who perceives it." [Footnote: La Nature de l'Ame, lecture 2.]