262 INDUCTION. 



in being unable to conceive that A can produce B, but finds the sequence 

 D B still more natural than C B, or of nearer kin to the subject-matter, and 

 prefers his D theory to the C theory. It is plain that there is no universal 

 law operating here, except the law that each person's conceptions are gov- 

 erned and limited by his individual experiences and habits of thought. 

 We are warranted in saying of all three, what each of them already be- 

 lieves of the other two, namely, that they exalt into an original law of the 

 human intellect and of outward nature one particular sequence of phe- 

 nomena, which appears to them more natural and more conceivable than 

 other sequences, only because it is more familiar. And from this judg- 

 ment I am unable to except the theory, that Volition is an Efficient Cause. 

 I am unwilling to leave the subject without adverting to the additional 

 fallacy contained in the corollary from this theory; in the inference that 

 because Volition is an efficient cause, therefore it is the only cause, and the 

 direct agent in producing even what is apparently produced by something 

 else. Volitions are not known to produce any thing directly except nerv- 

 ous action, for the will influences even the muscles only through the nerves. 

 Though it were granted, then, that every phenomenon has an efficient, and 

 not merely a phenomenal cause, and that volition, in the case of the pe- 

 culiar phenomena which are known to be produced by it, is that efficient 

 cause ; are we therefore to say, with these writers, that since we know of 

 no other efficient cause, and ought not to assume one without evidence, 

 there is no other, and volition is the direct cause of all phenomena? A 

 more outrageous stretch of inference could hardly be made. Because 

 among the infinite variety of the phenomena of nature there is one, namely, 

 a particular mode of action of certain nerves, which has for its cause, and 

 as we are now supposing for its efficient cause, a state of our mind ; and 

 because this is the only efficient cause of which we are conscious, being the 

 only one of which in the nature of the case we ca7i be conscious, since it is 

 the only one which exists within ourselves; does this justify us in conclud- 

 ing that all other phenomena must have the same kind of efficient cause 

 Avilh that one eminently special, narrow, and peculiarly human or animal, 

 phenomenon? The nearest parallel to this specimen of generalization is 

 suggested by the recently revived controversy on the old subject of Plural- 

 ity of Worlds, in M'hich the contending parties have been so conspicuously 

 successful in overthrowing one anothei'. Here also we have experience 

 only of a single case, that of the world in which we live, but that this is in- 

 habited we know absolutely, and without possibility of doubt. Now if on 

 this evidence any one were to infer that every heavenly body without ex- 

 ception, sun, planet, satellite, comet, fixed star or nebula, is inhabited, and 

 must be so from the inherent constitution of things, his inference would 

 exactly resemble that of the writers who conclude that because volition is 

 the efficient cause of our own bodily motions, it must be the efficient cause 

 of every thing else in the universe. It is true there are cases in which, 

 with acknowledged propriety, we generalize from a single instance to a 

 multitude of instances. But they must bo instances which resemble the 

 one known instance, and not such as have no circumstance in common with 

 it except that of being instances. I have, for example, no direct evidence 

 that any creature is alive except myself, yet I attribute, with full assur- 

 ance, life and sensation to other human beings and animals. But I do not 

 conclude that all other things are alive merely because I am. I ascribe to 

 certain other creatures a life like my own, because they manifest it by the 

 same sort of indications by which mine is manifested. I find that their 



