It is precision, M. Bergson suggests in his last book,1 that has most been lacking in philosophy. Imprecision declares itself in two respects: philosophical systems of the past apply indifferently to many imaginary worlds, and so allows this actual world to slip through their meshes; and they ignore the sense or direction evinced in the order and process of this actual world. Such systems “do not fit the reality in which we live, but are too large for it. Any of them would apply equally well to a world in which plants, animals, and men did not exist, or one in which men went without food and drink and did not sleep or dream or rave, to a world in which men were born decrepit and suckled in old age … Such systems of conceptions are so abstract, consequently so vast, that they can be made to hold everything possible alongside the real”. That we should interpret them always with an eye on this actual world and so regard them as being literal transcriptions of the actual is a witness to the practical bias of our thinking and a quite arbitrary reading of them. Contrasted with these highly abstract systems, M. Bergson claims that his own explanation “adheres to its object” and leaves no gap in which an alternative one could find foothold.