FALLACIES OF SIMPLE IXSPECTION. 465 



Brouni, in liis ti-eatise on Cause and Effect, has sliowii Avitli great 

 acuteness and justness of thouG;ht. We have before remarked, ihat 

 almost every fallacy may be refeircd to diHbrcnt genera by diilerent 

 modes of hlling up the suppressed steps, and this particular one may, 

 at our ojition, be bi'uught under jK'titio 2>/'i>i'''J'i'. It supposes that 

 nothing can be a " sufKcicnt reason" for a body's moving in one par- 

 ticulai- dii-ectiiin, except some external force. But this is the -very 

 thing to be proved. Wliy not some internal force ] Why hot the law 

 of the thing's own nature 1 Since these philosophers think it neces- 

 Bai^y to prove the law of inertia, they of course do not suppose it to be 

 sell'-evident ; they must, therefore, be of opinion that, ])rcviously to all 

 jnoof, the 8Ui)position of a body's moving by internal impulse is an 

 admissible hypothesLj r but if so, why is not the hypothesis also admis- 

 sible, that the internal impidsc acts naturally in' some one paiticular 

 direction, not in another I If spontaneous motion might have been 

 the law of matter, why not spontaneous motion towards the sun, 

 towards the earth, or towards the zenith \ A\'hy not, as the ancients 

 supposed, towards a particular place in the universe, appropriated to 

 each particular kind of substance 1 Surely it is not allowable to say 

 that spontaneity of motion is credible in itself, but not credible if sup- 

 posed to take place in any determinate directitm. 



Indeed, if any one chose to assert that all bodies when uncontrolled 

 set out in a direct line towards the north pole, he might ecpially prove 

 his point by the principle of the Sufficient Reason. By what right is 

 it assumed that a state of rest is the particular state which camiot be 

 deviated from without special cause ? Why not a state of motion, and 

 of some particular sort of motion ] Why may we not say that the 

 natural state of a horse left to himself is to amble, because otherwise 

 he must either trot, gallop, or stand still, and because \\e know no 

 reason why he should do one of these rather than another ( If this is 

 to be called an unfair use of the " sufficient reason," and the other a 

 fair one, there must be a tacit assumption that a state of rest is raorc 

 natural to a horse than a state of ambling. If this means tliat it is the 

 ;state which the animal will assume when lel'c to himself, that is the 

 vei,y point to be proved ; and if it does iu>\. moan this, it can only mean 

 that a state of rest is the simplest state, and therefore the most likely 

 to prevail in nature, which is one of the i'allacies or natural i)rejudices 

 we have already examined. 



So again of the First Law of Motion ; that a body once moving 

 Avill, if left to itself, contuuie to move unifonnly in a straight line. An 

 attempt is made to prove this law by saying, that if not, the body must 

 deviate either to the right or to the left, and that there is no reason 

 why it should do one more than the other. But who could jcnow, an- 

 tecedently to experience, whether there was a reason or not ] Might 

 it not be the nature of bodies, or of some particular bodies, to deviate 

 towards the right '. or if the supposition is preferred, towaids the east, 

 or south ? It wa.s long thought that l>odie.'*, tencistrial ones at least, 

 had a natural tendency to deflect downwards ; and there is no shadow 

 of anything objectionable in the; supj)osilion, except tliat it is not true. 

 The pretended proof of the law of motitm is oven more manifestly un- 

 tenable than that of the law of ineitia, for it is flagiaiitly inconsistent ; 

 it assumes that the continuance of motion in the direction first taken is 

 more natural than deviation either to the right or to the left, but denies 

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