THE NATURE OF PLEASURE AND PAIN. 687 



consider the question of why beings should live, or should desire to 

 live ; or why there are agreeable and useful variations which the 

 being should mate an effort to preserve. Now, external selection evi- 

 dently presupposes an internal spring, of necessity or spontaneity, 

 which produces, with life, the bound toward a higher life, the bound 

 of evolution. A German biologist, Mr. Rolph, looked for this spring 

 in the movement of assimilation by endosmose, which is characteristic 

 of all organized beings, or of all individual cells, and which he as- 

 sumed to be insatiable. In this view, we might then speak of a "me- 

 chanical hunger," or craving, as the cause of all the actions of living 

 organisms. Corresponding with this " mechanical hunger " appears, 

 at a particular stage of evolution, what Mr. Rolph calls " psychical 

 hunger," which makes itself felt at first essentially as pain ; while 

 pleasure is only " a secondary and derivative phenomenon." Hence it 

 results that pain is the motive spring of the universe. This theory is 

 intimately connected with the doctrine which assumes that the essence 

 of pleasure, or at least its necessary condition, is the suppression of 

 pain. Leibnitz has mentioned those infinitesimal and imperceptible 

 "little griefs" which, being suppressed, give "a quantity of half -pleas- 

 ures," the continuation and accumulation of which, " as in the con- 

 tinuation of the impulsion of a grave body, which gains impetuosity 

 as it falls," become at last a real and whole pleasure. " And at the 

 bottom," he adds, " without these half-griefs there would be no pleas- 

 ure, and we should have no means of perceiving that anything aids 

 and relieves us by removing the obstacles that hinder our setting our- 

 selves at ease." An Italian philosopher of the eighteenth century, 

 Verri, developing Leibnitz's thought, came to the conclusion that a 

 pain precedes every pleasure ; and the theory has been followed up 

 by Kant and Schopenhauer and the pessimists. 



To resolve this question which the pessimists have raised, we must 

 inquire whether there are any pleasures that make themselves felt 

 directly, without the intervention of a previous pain ; and whether 

 there can be motives to activity without the assistance of pain. It 

 appears to us that the pleasures of the higher senses, of sight, hearing, 

 and smell, and the mental pleasures, and those of science and art, be- 

 long to the latter category. A child, seeing a scarlet cloth for the first 

 time, gains an excitation of the sense of sight which is in no way the 

 suppression of a previous pain. To invoke in this case imperceptible 

 uneasiness and latent wants, and a tension of the optic nerve aspiring 

 to fulfill them, is to form a hypothesis which has a part of truth, but 

 does not wholly explain the phenomena. The pleasure here is not sim- 

 ply the exact filling of a void, or the adequate satisfaction of a pre-ex- 

 isting want ; it is a surplus, an addition. If we regard the scale of 

 intensities in sensation, we shall find that there is a point near to indif- 

 ference, departing from which some pleasures are capable of arising 

 by an increase of intensity. Not every pleasure supposes a previous 



