3 o POPULAR SCIENCE MONTHLY 



put together thus and so, information, important information, it may 

 well be, is given. But plainly our question is not answered, it is merely 

 pushed a step farther back. In the equations of science, it would seem, 

 matter is represented by an x, whose value is seldom sought. But with 

 everything made out of matter, it is certainly worth the while to search 

 out its intrinsic nature. 



Possibly then, since common sense and science appear to be equally 

 unable to say what matter is, the problem is beyond the scope of human 

 powers. May be, as Lord Dundreary says, it is one of those things 

 no fellow can tell. It may be so, but it is well to remember that the 

 discoveries of science have nearly all been things that the faint- 

 hearted said no fellow could tell. Besides, as regards the problem of 

 matter, no philosophic generation has ever been wholly agnostic, and 

 the foremost members of the present and latest scientific generation 

 are not agnostic. And, moreover — a point of especial significance — it is 

 well to remind ourselves that philosophers and scientists, in spite of 

 the difference of their points of view, and of their methods, seem 

 rapidly to be approaching agreement as to the nature of matter. It 

 should then repay us to hear what they have to say. 



Insisting, as we have seen, that sensations — colors, sounds, tastes 

 and the rest, are not matter, or any part of matter, philosophers — at 

 least those unconfused by Hume's oversophisticated attack on causes, 

 taken so seriously by Kant — these philosophers, I say, maintain that 

 sensations rightly studied tell us what matter is. Known directly, 

 and indirectly as effects of matter working on our senses, sensations, 

 critically considered, show matter to be a vastly complicated system 

 of active causes, occupying space, that and nothing more. 2 Each ma- 

 terial object is thus known to be a group of forces, more or less com- 

 plicated in their interplay, and varied as to their constituent elements. 

 The forces constituting a living cell are very varied in kind and 

 complicated in interplay, as compared with those composing an equal 

 volume of hydrogen gas; but complicated and varied forces are forces 

 none the less. Moreover, all kinds of matter have one quality in com- 

 mon, the forceful defense of the space they occupy. This is called 

 their solidity or impenetrability. Everything material opposes force 

 to attempted encroachment on its space, and, unless given room else- 

 where, absolutely prevents its entire appropriation; though all the forces 

 of the universe pressed upon a single drop of water, it could not be 

 annihilated. Thus impenetrability is the active defense of space. The 

 fundamental constituent of matter is force. 3 And other constituents 

 are the chemical, electrical and remaining physical activities, whose 



2 Nothing more so far as sensations of the special senses can help us to 

 know the intrinsic nature of matter. 



3 Some would prefer the term " energy," others " activity." I know of no 

 satisfactory term; but the thing denoted is real, many and baffling as are the 

 mysteries it contains. 



