12 THE POPULAR SCIENCE MONTHLY. 



sweep over its field of vision to and fro, here and there ; its movements 

 might conceivably be very numerous, but all the purposes of voluntary 

 acquirement might be served without a very great number. 



Because the muscles admit of all these possible stimuli, it does not 

 follow that the brain will ever impart them all. The limits of the mo- 

 tor centers would be the limits of the spontaneous impulses. The 

 workings of the system are brought within a narrow routine, from the 

 deficiency of the nervous matter. There are possibilities of combina- 

 tion of the muscles of the eyes that may never have been realized by 

 the educated eye, far less by the uneducated eye. 



Take, again, the swing of the limbs. Many muscles are at work, and 

 many possibilities of union are open ; but how few are actually realized ! 

 The supposition of the vastness of the possible combinations cuts two 

 ways : it opens up an almost infinite source of active capability. For, 

 although it might be long ere we reached some one particular combina- 

 tion, yet, out of the number of combinations that we might make, we 

 should fall upon manifold obvious utilities that would be soon confirmed 

 into useful habits. The same end may be served by many varieties of 

 means ; there might be fifty thousand routes of the hand to the mouth, 

 but, provided it got there anyhow, all would end well. The observation 

 would apply generally to Professor Spence's millions of possibilities : 

 many thousands of them would equally hit the same mark. 



5. I might dwell at greater length on the two limiting considerations 

 now adduced ; that is to say (1), the limits of the central mechanism, 

 and (2) the equal suitability of many thousands o'f the supposed pos- 

 sible combinations to given ends. I go on, however, to cite the most 

 important qualification of all the self-controlling power of the active 

 mechanism. This is the assumption needed to account for the origin of 

 voluntary power, whether in the individual or in the race. To expati- 

 ate upon this would only be to repeat what I have said in my writings ; 

 and I could not, in a short space, say anything that would be likely to 

 satisfy Professor Spence. I prefer for what remains of my paper to 

 comment upon his own theory, namely, the doctrine of heredity or 

 evolution, which he puts forward as the true solution of the difficulties 

 of the will. In the first place, however, I refer him to " The Emotions 

 and the Will," third edition, p. 318, where I endeavor to show that the 

 postulates of my theory of will namely, spontaneity, the law connect- 

 ing pleasure with increased vitality, and the contiguous growth of ac- 

 cidental connections are indispensable to the evolution doctrine, as 

 stated by Spencer and Darwin. What I mean now to affirm is, that pre- 

 cisely the same difficulty, arising from millions of possibilities of com- 

 bined action, occurs at every step of our progress by evolution. The 

 only thing that serves to abate the difficulty is that, when a happy com- 

 bination is once struck, it is hereditarily transmitted and becomes a 

 possession for ever. This would be an important mitigation, if heredi- 

 tary transmission were easily and soon effected ; but the facts show 



