ABSTRACT
IN close connection with assimilation stands, as we saw above, the successive association of ideas. This is the process to which the general name of ‘association’ was originally confined; and it is still customary, even at the present day, to speak of laws of association, and to distinguish in that way connection by similarity from that by co-existence in space or succession in time, or sometimes from that by contrast. It is scarcely necessary to say that these are really simply forms, and not laws, of association; they are not universally valid conditions of its origin. They merely serve to furnish classificatory concepts under which the ready-made products of association can be subsumed. But, curiously enough, the authority of Aristotle and the constant inclination of the human mind towards logical schematisation have worked no less harm in this department of psychology than they worked in the sciences of nature. Aristotle had distinguished four kinds of memory, in terms of the logical opposites ‘similarity’ and ‘contrast,’ ‘simultaneity’ and ‘succession’: just as he had arranged the fundamental qualities of all natural bodies under the rubrics of the contraries ‘hot’ and ‘cold,’ ‘moist’ and ‘dry.’ And these four forms have held the field, despite the evidence of observation, down to our own day. It is now pretty generally agreed that ‘contrast’ may be omitted, or, where anything corresponding to it occurs, referred to ‘similarity’; while spatial co-existence and temporal succession are brought under the general head of external contiguity. This means a reduction of the four forms to two,—association by similarity and association by contiguity. And the reduction is so far good that the different cases of successive connection may, as a rule, be arranged in one or other of the two classes. At the same time, the terms still tend to suggest the wrong idea: that they are the distinguishing marks of elementary processes, instead of the classificatory headings of association-products, each of which is constituted by a whole number of simple processes. In the matter of constituents there is, of course, no essential distinction to be drawn between the two forms. For it is obvious that just the same processes must be operative in successive association as in assimilation,—the only difference between them being that the successively associated ideas are not combined into one simultaneous idea, but remain temporally separate, in obedience to conditions which we have still to discuss.
