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INDUCTION. 



all of them at once, he might be able, 

 by piecing together his successive 

 observations, to discover both that 

 it was an ellipse and that th^ planet 

 moved in it. The case would then 

 exactly resemble that of the naviga- 

 tor who discovers the land to be an 

 island by sailing round it. If the 

 path was visible, no one I think 

 would dispute that to identify it 

 with an ellipse is to describe it : 

 and I cannot see why any differ- 

 ence should be made by its not being 

 directly an object of sense, when 

 every point in it is as exactly ascer- 

 tained as if it were so. 



Subject to the indispensable con- 

 dition which has just been stated, 

 I do not conceive that the part which 

 conceptions have in the operation of 

 studying facts has ever been over- 

 looked or undervalued. No one ever 

 disputed that in order to reason about 

 anything we must have a conception 

 of it ; or that when we include a 

 multitude of things under a general 

 expression, there is implied in the 

 expression a conception of something 

 commoii to those things. But it by 

 no means follows that the conception 

 u necessarily pre-existent, or con- 

 structed by the mind out of its own 

 materials. If the facts are rightly 

 classed under the conception, it is 

 because there is in the facts them- 

 selves something of which the con- 

 ception is itself a copy ; and which 

 if we cannot directly perceive, it is 

 because of the limited power of our 

 organs, and not because the thing 

 itself is not there. The conception 

 itself is often obtained by abstraction 

 from the very facts which, in Dr. 

 Whewell's language, it is afterwards 

 called in to connect. This he himself 

 admits, when he observes, (which he 

 does on several occasions,) how great 

 a service would be rendered to the 

 science of physiology by the philoso- 

 pher ** who should establish a precise, 

 tenable, and consistent conception of 

 life." * Such a conception can only 



* Novum Orffanum Jienovatuvi, p. 32. 



be abstracted from the phenomena of 

 life itself ; from the very facts which 

 it is put in requisition to connect. 

 In other cases, no doubt, instead of 

 collecting the conception from the 

 very phenomena which we are at- 

 temptmg to colligate, we select it 

 from among those which have been 

 previously collected by abstraction 

 from other facts. In the instance of 

 Kepler's laws, the latter was the case. 

 The facts being out of the reach of 

 being observed in any such manner 

 as would have enabled the senses to 

 identify directly the path of the 

 planet, the conception requisite for 

 framing a general description of that 

 path could not be collected by abstrac- 

 tion from the observations themselves ; 

 the mind had to supply hypotheti- 

 cally, from among the conceptions it 

 had obtained from other portions of 

 its experience, some one which would 

 correctly represent the series of the 

 observed facts. It had to frame a 

 supposition respecting the general 

 course of the phenomenon, and ask 

 itself. If this be the general descrip- 

 tion, what will the details be ? and 

 then compare these with the details 

 actually observed. If they agreed, 

 the hypothesis would serve for a de- 

 scription of the phenomenon : if not, 

 it was necessarily abandoned, and 

 another tried. It is such a case as 

 this which gives rise to the doctrine 

 that the mind, in framing the de- 

 scriptions, adds something of its own 

 which it does not find in the facts. 



Yet it is a fact surely that the 

 planet does describe an ellipse ; and 

 a fact which we could see if we had 

 adequate visual organs and a suitable 

 position. Not having these advan- 

 tages, but possessing the conception 

 of an ellipse, or (to express the mean- 

 ing in less technical language) know- 

 ing what an ellipse was, Kepler tried 

 whether the observed places of the 

 planet were conwstent with such a 

 path. He found they were so ; and 

 he, consequently, asserted as a fact 

 that the planet moved in an ellipse. 

 But this fact, which Kepler did not 



