224 OPERATIONS SUBSIDIARY TO INDUCTION. 



originally came, or the place where a great quantity 

 of matter similar to itself was assembled. In the 

 other class of motions, as when bodies are thrown up 

 in the air, they are, on the contrary, moving from 

 their own place. Now, this conception of a body 

 moving towards its own place may justly be consi- 

 dered inappropriate; because, though it expresses a 

 circumstance really found in some of the most familiar 

 instances of motion apparently spontaneous, yet, first, 

 there are many other cases of such motion, in which 

 that circumstance is absent: the motion, for instance, 

 of the earth and planets. Secondly, even when it is 

 present, the motion, on closer examination, would 

 often be seen not to be spontaneous: as, when air 

 rises in water, it does not rise by its own nature, but 

 is pushed up by the superior weight of the water 

 which presses upon it. Finally, there are many 

 cases in which the spontaneous motion takes place 

 in the contrary direction to what the theory considers 

 as the body's own place; for instance, when a fog 

 rises from a lake, or when water dries up. There is, 

 therefore, no agreement, but only a superficial sem- 

 blance of agreement, which vanishes on closer inspec- 

 tion: and hence the conception is u inappropriate." 

 We may add that, in the case in question, no con- 

 ception would be appropriate; there is no agreement 

 which runs through all the cases of spontaneous, or 

 apparently spontaneous, motion: they cannot be 

 brought under one law it is a case of Plurality of 

 Causes*. 



* Other examples of inappropriate conceptions are given by 

 Mr. Whewell (Phil. Ind. Sc. ii., 185), as follows: " Aristotle 

 and his followers endeavoured in vain to account for the mechanical 

 relation of forces in the lever, by applying the inappropriate geo- 

 metrical conceptions of the properties of the circle: they failed in 



