Tlie Philosophy of Evolution. 51 



the complex. Induction can proceed only by assuming a 

 genus at the outset — that is, by assuming certain attributes in 

 the individual to be generic. Translate this law into mate- 

 rial forms, and we have each higher — that is more complex — 

 species evolved from the lower by the addition of some new 

 characteristic. This new attribute cannot be added by the 

 functional activity of the lower organism ; that can only re- 

 produce itself. A thought does not change merely through 

 repeated expression. We pass to the conclusion of a syllogism, 

 not from each term, but from a comparison of the premises — 

 and this requires an intellectual operation entirely distinct from 

 a mere apprehension of the terms. It is one thing to compre- 

 hend the premises ; it is quite another to deduce a conclusion 

 from them. It may necessarily follow, but it requires a separate 

 act of the mind to reach it. Premises will not of themselves 

 reach a conclusion. 



Eeading this same truth in the forms of matter, we may say 

 that species will not pass into higher species without the inter- 

 vention of a force distinct from either. The impulse which 

 adds a new attribute must be intellectually separable from all 

 those pre-existing, and its material representation must be 

 physically distinct from pre-existing forms. This complete 

 separability precludes the possibility of mere physical genesis. 

 The added attribute is presented by a new form of matter, re- 

 vealing the presence of a new thought — a new effect, requiring 

 the agency of a new cause. In accordance with the usual 

 economy of nature, who never duplicates her forces, change 

 will be made only so far as may be necessary to communicate 

 the additional idea. Organisms representing previous thoughts 

 will be added to, in order to express the expansion of the 

 thought, instead of a creation de novo in each instance. Thus 

 an indentical cellular structure will be found in all organic 

 beings, from the lowest to the highest, each higher type carry- 

 ing forward tha idea and its physical expression found in the 

 lower. The differences between no two terms in the series can 



