ULTIMATE SCIENTIFIC IDEAS. 61 



sensations there is no reason to believe it like any. It suf- 

 fices to remark that since the force as known to us is an 

 affection of consciousness, we cannot conceive the force ex- 

 isting in the chair under the same form without endowing 

 the chair with consciousness. So that it is absurd to think 

 of Force as in itself like our sensation of it, and yet neces- 

 sary so to think of it if we realize it in consciousness at all. 

 How, again, can we understand the connexion between 

 Force and Matter? Matter is known to us only through its 

 manifestations of Force: our ultimate test of Matter is the 

 ability to resist: abstract its resistance and there remains 

 nothing but empty extension. Yet, on the other hand, re- 

 sistance is equally unthinkable apart from Matter — apart 

 from something extended. Not only, as pointed out some 

 pages back, are centres of force devoid of extension unimag- 

 inable; but, as an inevitable corollary, we cannot imagine 

 either extended or unextended centres of force to attract 

 and repel other such centres at a distance, without the inter- 

 mediation of some kind of matter. We have here to remark, 

 what could not without anticipation be remarked when 

 treating of Matter, that the hypothesis of Newton, equally 

 with that of Boscovich, is open to the charge that it supposes 

 one thing to act upon another through a space which is abso- 

 lutely empty — a supposition which cannot be represented 

 in thought. This charge is indeed met by the introduction 

 of a hypothetical fluid existing between the atoms or cen- 

 tres. But the problem is not thus solved : it is simply shift- 

 ed, and re-appears when the constitution of this fluid is in- 

 quired into. How impossible it is to elude the diffi- 

 culty presented by the transfer of Force through space, is 

 best seen in the case of astronomical forces. The Sun acts 

 upon us in such way as to produce the sensations of light and 

 heat ; and we have ascertained that between the cause as ex- 

 isting in the Sun, and the effect as experienced on the Earth, 

 a lapse of about eight minutes occurs: whence unavoidably 

 result in us, the conceptions of both a force and a motion. 



