But our own nature, the office and the function of our personality, remain enveloped in equal mystery. For these elementary unextended sensations which develop themselves in space, whence do they come, how are they born, what purpose do they serve? We must posit them as so many absolutes, of which we see neither the origin nor the end. And even supposing that we must distinguish, in each of us, between the spirit and the body, we can know nothing either of body or of spirit, nor of the relation between them.
Now in what does this hypothesis of ours consist, and at what precise point does it part companyAction, not sensation, should be the starting point. with the other? Instead of starting from affection, of which we can say nothing, since there is no reason why it should be what it is rather than anything else, we start from action, that is to say from our faculty of effecting changes in things, a faculty attested by consciousness and towards which all the powers of the organized body are seen to converge. So we place ourselves at once in the midst of extended images; and in this material universe we perceive centres of indetermination, characteristic of life. In order that actions may radiate from these centres, the movements or influences of the other images must be on the one hand received and on the other utilized. Living matter, in its simplest form, and in a homogeneous state, accomplishes this function simultaneously with those of nourishment and repair. The progress of such matter consists in