argue that such conduct is that of a very highly rational being. In reality the objective examination of man’s behaviour, if attention is directed to the facts and not to what the actors think of them, yields at once in every field example after example of similar irrational features. When the influence of civilization is looked upon as having rendered man’s instincts of altogether secondary importance in modern life, it is plain that such a conclusion involves a misconception of the nature of instinct. This well-worn term has come to have so vague a connotation that some definition of it is necessary. The word “instinct” is used here to denote inherited modes of reaction to bodily need or external stimulus. It is difficult to draw a sharp distinction between instinct and mere reflex action, and an attempt to do so with exact precision is of no particular value. In general we may say that the reactions which should be classed under the head of instinct are delayed (that is, not necessarily carried out with fatal promptitude {95} immediately upon the stimulus), complex (that is, consist of acts rather than mere movements), and may be accompanied by quite elaborate mental processes. In a broad way also it may be said that the mental accompaniments of an instinctive process are for the most part matters of feeling. During the growth of the need or stimulus there will be a desire or inclination which may be quite intense, and yet not definitely focused on any object that is consciously realized; the act itself will be distinguished to the actor by its rightness, obviousness, necessity, or inevitableness, and the sequel of the act will be satisfaction. This mere hint of the psychical manifestations of instinctive activity leaves quite out of account the complex effects which may ensue when two instinctive impulses that have come to be antagonistic reach the mind at the same time. The actual amount of mental activity which accompanies an instinctive process is very variable; it may be quite small, and then the subject of it is reduced to a mere automaton, possessed, as we say, by an ungovernable passion such as panic, lust, or rage; it may be quite large, and sometimes the subject, deceived by his own rationalizations and suppressions, may suppose himself to be a fully rational being in undisputed possession of free will and the mastery of his fate at the very moment when he is showing himself to be a mere puppet dancing to the strings which Nature, unimpressed by his valiant airs, relentlessly and impassively pulls.