VOLUNTARY MOTION. 445 



To the superficial observer, a human being, during the interval be- 

 tween birth and adult life, seems to learn a great deal; but, if he did 

 really learn all that he seems to learn, it would be marvelous in a de- 

 gree wholly beyond the power of the human mind to conceive of, and 

 far beyond the power of human language to express. Omitting, at 

 present, that immense domain of the mind which is embraced under 

 the terms sensation, emotion, and intellection, we will endeavor to 

 make a comparative estimate as to how much we seem to learn, but 

 do not learn, and how much we do really learn, in that limited 

 department of the will which is covered by the term voluntary 

 motion. 



We will begin by endeavoring to ascertain how much a child would 

 have to acquire in simply learning to pronounce the letter A, at will, 

 supposing that none of the movements, or combinations of movements, 

 which are made in the utterance of that one sound, are organic and in- 

 herited, but that they all have to be acquired or learned by practice 

 and experience. 



Between the states of the greatest and the least contraction of any 

 muscle of the body, there are, of course, an infinite number of degrees 

 of contraction. In order, however, that we may not seem to exaggerate 

 the difficulties of the child's task, we will suppose that a muscle is sus- 

 ceptible of only three degrees of contraction, and that, therefore, three 

 experiments, at most, would ultimate in the production of the sound of 

 A, supposing it to depend upon the proper contraction of only one 

 muscle. But how many muscles are engaged in the production of that 

 one sound ? A great many, namely, the muscles of the vocal chords, 

 the muscles of the back part of the mouth, of the tongue, the cheeks, 

 the lips, and the muscles that expand and contract the chest. We will 

 largely understate their number, and suppose that there are only 20 

 involved in the pronunciation of A, each one of which, as we have al- 

 ready supposed, is susceptible of only 3 distinct degrees of contraction. 

 Now, 2 muscles, each one of which is susceptible of 3 degrees of con- 

 traction, can be made to contract together in 9 different combinations, 

 consisting of one degree of the contraction of each muscle to each 

 combination ; 3 muscles will give 27 possible combinations, 4 muscles 

 81 possible combinations, and so on, in a geometrical ratio of increase, 

 up to the supposed 20 muscles, with which there would be 3,113,884,401 

 possible combinations of muscular contractions. Now, in all this wilder- 

 ness of possibilities, there is but one combination which can produce 

 the sound of the letter A, and that one the child must find, although, 

 according to the supposition, he knows nothing about it, and has no 

 organic tendencies in the direction toward it. He can find it only by 

 experiment. Each possible combination must be successively tried and 

 rejected, until he comes to the right one. Assuming that his chances 

 of hitting upon the right combination are equal to his chances of 

 missing it, the number of experiments which he would have to make, 



