perception, the living synthesis of pure perception and pure memory, necessarily sums up in its apparent simplicity an enormous multiplicity of moments. Between sensible qualities, as regarded in our representation of them, and these same qualities treated as calculable changes, there is therefore only a difference in rhythm of duration, a difference of internal tension. Thus, by the idea of tension we have striven to overcome the opposition between quality and quantity, as by the idea of extension that between the inextended and the extended. Extension and tension admit of degrees, multiple but always determined. The function of the understanding is to detach from these two genera, extension and tension, their empty container, that is to say, homogeneous space and pure quantity, and thereby to substitute, for supple realities which permit of degrees, rigid abstractions born of the needs of action, which can only be taken or left; and to create thus, for reflective thought, dilemmas of which neither alternative is accepted by reality.
3rd. But if we regard in this way the relations of the extended to the inextended, of qualityFreedom and necessity. to quantity, we shall have less difficulty in comprehending the third and last opposition, that of freedom and necessity. Absolute necessity would be represented by a perfect equivalence of the successive moments of duration, each to each. Is it so with the duration
