Vlll PREFACE. 



enter ; and they turn away in despair. I admit 

 the merit of the systems and subdivisions: for 

 those who devote themselves to a single science, 

 they are admirable ; but to the great body of the 

 people they are worse than useless. 



With many works that profess to be popular, 

 the case is not better. They are in general col- 

 lections of scraps, put together by persons of no 

 observation, the illustrations of a system without 

 the system itself, and therefore of little use to 

 any body. The facts that they set forth may be 

 true ; but when one puts the cui bono, there is no 

 answer; and when one seeks for the connexion 

 by which all the parts are united into a whole, it 

 is not to be found. 



Some part of this may be owing to the mischief 

 of authority ; and of the authority of one of the 

 greatest men that ever lived. Bacon, forgetting 

 for once the difference between matter of fact and 

 matter of inference, said, rather inconsiderately, 

 that " final causes produce nothing." The sentence 

 is a mere opinion, and, what is more, it is a contra- 

 diction ! as, if the causes be final, what can they 

 produce ? But the sentence has become a maxim ; 

 final causes are but seldom attended to, and the 

 history of nature, thus disjointed, becomes unin- 

 teresting. Yet final causes are, in the study of 

 organic being, what the laws of matter are in the 

 study of mere material existence, or what the 

 principles of arithmetic and geometry are in the 



