With regard to the relation of the two senses which we have just distinguished, common opinion seems very precise. It might be thus resumed: at the point of departure we have simple sensations, similar to qualitative atoms (this is the part of pure perception), and afterwards their arrangement into connected systems, which are percepts. But criticism does not authorise this manner of looking at it. Nowhere does knowledge begin by separate elements. Such elements are always a product of analysis. So there is a problem to solve to regain the basis of pure perception which is hidden and obscured by our familiar percepts. Do not suppose that the solution of this problem is easy. One method only is of any use: to plunge into reality, to become immersed in it, in a long-pursued effort to assimilate all the records of common-sense and positive science. "For we do not obtain an intuition of reality, that is to say, an intellectual sympathy with its inmost content, unless we have gained its confidence by long companionship with its superficial manifestations. And it is not a question merely of assimilating the leading facts; we must accumulate and melt them down into such an enormous mass that we are sure, in this fusion, of neutralising in one another all the preconceived and premature ideas which observers may have unconsciously allowed to form the sediment of their observations. Thus, and only thus, is crude materiality to be disengaged from known facts." ("Introduction to Metaphysics" in the "Metaphysical and Moral Review", January 1903. For the correct interpretation of this passage ("intellectual sympathy") it must not be forgotten that before "Creative Evolution", Mr Bergson employed the word "intelligence" in a wider acceptation, more akin to that commonly received.) A directing principle controls this work and reintroduces order and convergence, after dispensing with them at the outset; viz. that, contrary to common opinion, perception as practised in the course of daily life, "natural" perception does not aim at a goal of disinterested knowledge, but one of practical utility, or rather, if it is knowledge, it is only knowledge elaborated in view of action and speech. Need we repeat here the proofs by which we have already established in the most positive manner that such is really the meaning of ordinary perception, the underlying reason which causes it to take the place of pure perception? We perceive by habit only what is useful to us, what interests us practically; very often, too, we think we are perceiving when we are merely inferring, as for example when we seem to see a distance in depth, a succession of planes, of which in reality we judge by differences of colouring or relief.