ASSOCIATION AND THOUGHT. 361

uses a scientific fiction. It is convenient to speak of the movement of each element, but we must not assert (or deny) that in reality the element can do or be anything unless, indeed, we are prepared to make psychology a battle-field for metaphysicians. We have so far seen that Association can be reduced to the struggle of each element towards an independent totality by means of sameness in content, and that this principle works by-coalescence where the conditions are given, and, again, by redintegration made through the establishment of connexions superior to time. And if we like to call the movement an ideal process, this may distinguish it from what is by comparison mechanical, the basis upon which alone it exists and to which it has to suit itself. I must now point out this machinery, though I fear without completeness. There is first the incoming of fresh sensations, external and internal, partly new and in part the same. There is the disappearance of old ones, caused I will not here ask how. There is the limit to the amount of what can come to us at once, a limit varying but effective. We see here the condi- tions of another kind of struggle, a struggle for existence among actual facts, alongside of the former struggle through identity, but crossing it at times and blending with it in- extricably. In this more mechanical conflict what favours individuals ? We must mention first habit, aptitudes pro- duced by repetition, or got by heredity, or again in some way not known. Elements suited to these are strengthened, and in some cases also enlarged, and so tend to dominate. Where these aptitudes depend on ideal connexions they are instances of association, but where or so far as there is no psychical revival this is not the case. I think that psychology must accept this fact as an ultimate, unless it will venture on Herbart's startling assumptions or deviate into physiology. Passing by this, we come next to mere natural strength of presentation. If we wish to get this bare, we must look for it in ' disparate ' sensations, those which possess no special common character. 1 Strength will here amount simply to prevalence or domination. That which occupies more mental space than, or again totally or partially excludes, something else is said to have more force. And it has bare force when it prevails, not by virtue of aught else (such as 1 All sensations, in my judgment, do possess some common character. This will hold good whether we do or do not accept the view that the special sense continua have been differentiated from one primitive con- tinuum. See Horwicz, Psych. Analysen.