 Second, we turn to Bergson’s account of the “complexification” of life, that is, the phenomenon of its evolution from the simple original vital impulse into different species, individuals, and organs. The successive series of bifurcations and differentiations that life undergoes organize itself into two great opposite tendencies, namely, instinct and intelligence. Bergson arrives at this fundamental distinction by considering the different modes through which creatures act in and know the external world. Animals are distinguished from plants on the basis of their mobility, necessitated by their need to find food,whereas plants survive and grow through photosynthesis, which does not require locomotion. While the relationship between consciousness and matter instantiated in the instinct of animals is sufficient and well adapted to their survival (from the point of view of the species), humans are not adequately equipped in this respect; hence the necessity of something like intelligence, defined by the ability to make tools. Humanity is essentially homo faber. Once again, from the point of view of real, concrete life that Bergson is here embracing, intelligence is essentially defined by its pragmatic orientation (and not speculation, as a dogmatic intellectualist approach would assume). From this, Bergson deduces not only the cognitive structure and the scientific history of intelligence (which he examines in detail), but also its limitations. This essentially pragmatic, hence analytic and quantitative orientation of intelligence precludes its immediate access to the essentially qualitative nature of life. Notice that the distinction between the two tendencies relies on the original distinction between the qualitative and the quantitative multiplicities. In any case, in order that human intelligence may attain true knowledge of the essence of the vital impulse, it will have to proceed by means of a mode of knowing that lies at the opposite end of intelligence, namely, instinct.