22 THE POPULAR SCIENCE MONTHLY, 



space as occupied, and all motion produced by transfer to bodies in 

 contact, the origin of motion is indeed reduced to a concept derived 

 from our sense-experiences, but this view has also its difficulties. To 

 mention only one of these, it is impossible in this hypothesis to ex- 

 plain the diflferent densities of bodies from different combinations of 

 a homogeneous original matter. 



The origin of these contradictions is readily detected. They have 

 their root in our incapacity to conceive of any thing save what we 

 have experienced by either our external or our internal sense. In our 

 endeavor to analyze the physical world, we start out from the divisi- 

 bility of matter, the parts being to our eyes something simpler and 

 more primitive than the whole. When in thought we carry on this 

 division of matter ad infinitum^ we act in perfect accordance with our 

 sense-perceptions, and we meet with no obstacle in the process. But 

 we make no advance whatever toward an understanding of things, 

 since we, in fact, carry over into the region of the minute and the 

 invisible the concepts we obtained in the region of the gross and the 

 visible. Thus it is that we acquire the notion of the physical atom. 

 If now we arbitrarily stop the process of dividing at some point where 

 we are supposed to have reached philosophical atoms, that are indi- 

 visible, perfectly hard, and furthermore j9er se inefficient, being merely 

 the carriers of the central forces, we are expecting that a matter 

 which we think of under the concept of matter as known to us should, 

 without the aid of any new principle of explication, develop new 

 primordial properties, to explain the nature of bodies. Thus we com- 

 mit the error which is manifested in the previously-mentioned contra- 

 dictions. 



Xo one, that has bestowed any thought on this subject, can fail 

 to acknowledge the transcendental nature of the obstacles that face 

 us here. However we try to evade them, we ever meet them in one 

 form or another. From whatever side we approach them, or under 

 whatsoever cover, they are ever found invincible. The ancient Ionian 

 physical philosophers were no more helpless than we in presence of 

 this difficulty. The natural sciences, with all the progress they have 

 made, have availed naught against it, nor will their future progress be 

 of any greater effect. We shall never know any better than we now 

 do (to use the words of Paul Erman), " was hier im Haume spuht^'' 

 the spectre that haunts the world of matter. For even the mind im- 

 agined by Laplace, exalted as it would be high above our own, would 

 in this matter be possessed of no keener insight than ourselves, and 

 hence we despairingly recognize here one of the limitations of our 

 understanding. 



But if we turn aside from this primordial limit, and postulate matter 

 and force as understood, then, as we have said, the physical world is 

 intelligible ideally. From the original condition of a revolving nebu 

 lar sphere, the Kantian hypothesis, as further develo23ed by Helm- 



