1 8 THE SCIENCE OF LIFE. 



mass, proves atoms to be real physical existences. All 

 chemical science is based on the doctrine that atoms and 

 molecules have weight, definite proportions or relations, 

 and hence definite form. The law of Avogadro and Am- 

 pere, as it is called, that " equal volumes of all substances 

 when in the state of gas, and under like conditions, con- 

 tain the same number of molecules," is confirmed by all 

 chemical experiments, and necessarily implies the reality 

 of atoms and molecules. Our own consciousness of 

 matter, also, the sense of otherness which pertains to 

 our knowledge of the objects of sense, is as reliable as 

 any other knowledge. We know the otherness, as well 

 as the weight and inertia of matter by the same faculties 

 by which we know that two and two make four, and not 

 five. The obvious distinctions between the living and 

 the not living are all proofs of Dualism. 



9. As to the theory that atoms have a physical and a 

 spiritual side, by which opposite qualities are exhibited, 

 it carries its own refutation, since it is plainly impossible 

 for a healthy mind to believe that contrary properties can 

 inhere in any thing at the same time. Mr. Joseph Cook 

 has pertinently said : " If matter is a double-faced unity, 

 having a spiritual and a physical side, there must co- 

 inhere in one and the same substratum extension and 

 the absence of extension, inertia and the absence of iner- 

 tia, color and the absence of color, form and the absence 

 of form. To assert that these fundamentally antago- 

 nistic qualities of matter and mind not only inhere, but 

 co-inhere, in one and the same substratum, is to assert 

 that a thing can be and not be at the same time and in 

 the same sense. This limitless self-contradiction wrecks 



