as factors of survival, yet even in the highest animals, e.g. in man, for whom the environment is most complex and heterogeneous, both are present as essential factors of survival. In them reflex action by means of particular reactions still provides against particular and generally oft-recurring events, of such a kind as, if not provided against, would result in the destruction of the organism or of the species. As examples of such reflex actions present in man may be quoted, the movements of various hollow viscera, the acts of breathing, swallowing, and coughing, and in infants, that of sucking. Instinct is represented by various emotions, the existence of which is necessary for the preservation of the individual, or of the race, e.g. sexual and parental love, love of life, jealousy, rage, fear, hate, &c.[1] Generally speaking, reflex action and instinct provide reactions against such events as invariably happen to every individual, and are of such a nature as, if not provided against by unfailing machinery, would lead to destruction of the individual, or at any rate to cessation of the race; and this machinery, as I have said, is obviously inborn and transmissible.
But reason is obviously neither inborn nor transmissible. It is obviously acquired anew by every individual, only the power of acquiring it being inheritable; and the extent to which it is acquired in each organism depends (1) on the organism's power of varying, of
- ↑ Sexual and parental love, fear, and love of life are clearly necessary for the preservation of the race or of the individual, on whose preservation depends that of the race. As regards hate, that individual who has not the instinct is less likely to survive and have offspring than the individual who, having it, seeks to injure or destroy those that seek to injure and destroy him; so also with the instinct of rage; as regards jealousy, an individual, who views with indifference the advances made to his mate or mates by individuals of his own sex, is likely to have a smaller share in continuing the race than an individual who resents such advances.
