In order to escape such consequences we must, with Mr Bergson, reintroduce real duration, that is to say, creative duration into evolution, we must conceive life according to the mode exhibited with regard to change in general. And it is science itself which calls us to this task. What does science actually tell us when we let it speak instead of prescribing to it answers which conform to our preferences? Vitality, at every point of its becoming, is a tangent to physico-chemical mechanism. But physico-chemistry does not reveal its secret any more than the straight line produces the curve. Consider the development of an embryo. It summarises the history of species; ontogenesis, we are told, reproduces phylogenesis. And what do we observe then? Now that a long sequence of centuries is contracted for us into a short period, and that our view is thus capable of a synthesis which before was too difficult, we see appearing the rhythmic organisation, the musical character, which the slowness of the transitions at first prevented us from seeing. In each state of the embryo there is something besides an instantaneous structure, something besides a conservative play of actions and reactions; there is a tendency, a direction, an effort, a creative activity. The stage traversed is less interesting than the traversing itself; this again is an act of generating impulse, rather than an effect of mechanical inertia. So must the case be, by analogy, with general evolution. We have there, as it were, a vision of biological duration in miniature; expansion and relaxation of its tension bring its homogeneity to notice, but at the same time, properly speaking, evolution disappears. And further, Mr Bergson establishes by direct and positive arguments that life is genuine creation. A similar conclusion is presented as the envelope of his whole doctrine.