The struggle for existence is itself on the very face of it an expression of mind, namely, activity significant of certain will and feeling experience. Whatever shows mind is expression, and thus in a large sense every movement in the physical universe—and what is the universe but motion—and every organic activity may be construed as expression. Whether all force, motion, action, is or must be expression is, however, a philosophic investigation which we need not now discuss, though we may suspect that the height and depth of mind and so the range of expression is enormously beyond the science of to-day. However, restricting ourselves to the domain of animal life, it is obviously very difficult to determine just what activities of a given organism betray mind, and still more just what form of mentality is manifesting itself. Man, being the measure of all things, interprets himself in all, and even when he becomes aware of the dangers of anthropomorphism he cannot wholly disengage himself from the tendency. The subjective analogical interpretation is a necessary evil. Still man is the keenest sighted of all beings for expression, and actions in a very wide range which had not in fact the real function of expression become expressive to him. The primary value of fear for the deer is to make it run from danger, and the running becomes expressive of the fear to observers, though the running is not for the expression. Thus vital activities of many kinds are expressive, though their primary value is not in the expression. Activities whose sole or main value is to give expression are comparatively late, the value of expression in this narrow sense being in the mental impression thereby made upon other organisms. Thus actions which serve purely to frighten others, in making one’s self formidable by loud noises, as roar of lion, bark of dog, by erecting the hair, displaying claws, teeth, and other such actions are pure expressions.