It appears to us that, by a psychological interpretation of physiological facts, these laws can be reduced to one superior and really primitive law. Some have sought the meaning of the law of proportion, which demands that the positive labor of exercise bear a just relation with the negative labor of reparation, in the theory of a just mean, or a kind of golden mediocrity, by which the fundamental law of sensibility would be equilibrium, not action pure and simple. This is confounding the limit of a thing with its essence. Moderation, in itself, is not pleasure, nor the primitive law of life. It is a necessity which life encounters and submits to according to the needs of the organism. The true primary law is that pleasure is connected with the most intense possible activity; and this is, besides, the true condition of superiority in the struggle for existence. For this reason, if the increase of the activity or of the exercised function does not exceed the reserve of forces and wear upon the organ, the pleasure increases with the activity, without regard to moderation. If excess of muscular motion produces pain, it is because, not proportioning our actions to the strength of our organs, we wear upon them. The supposed increase of activity is then really a diminution.
Another problem is met in seeking the reason for the necessity of a change of action, for which contemporary psychologists, like Mr. Bain and Mr. Sully, have propounded the law of contrast as opposed to the laws of stimulation and moderation. It is in reality, however, derivable from the same principle as the other law. Change in action is only a means of assuring continued intensity of action. It makes other nerves to work while the former ones rest, and, effecting a separation of the nerves after this manner, augments the vital power.
To enjoy is, then, to act as much as possible with the greatest intensity, independence, and liberty. Activity, by itself, goes on infinitely. It moderates itself only by necessity and constraint, only to have afterward to moderate itself less, and to deploy itself beyond all the limits successively erected before it.
It might say, with Faust: "If ever I stretch myself, calm and composed, upon a couch, be then at once an end of me. If thou canst ever flatteringly delude me into being pleased with myself if thou canst cheat me into enjoyment—be that day my last. If I ever say to the passing moment, 'Stay, thou art so fair!' then mayst thou cast me into chains; then I will readily perish; then may the death-bell toll; . . . the clock may stand, the index hand-may fall; be time a thing no more for me."
Activity changes, therefore, only to maintain itself, to adapt itself progressively to the medium which changes, to increase its conquests without losing its acquisitions. In the evolution of species, this expansion of activity has always been a condition of survival and of superiority over other species.
Some authors have maintained that the final intensity of the action
