88 THE REIGN OF LAW. 



thumb. Yet who can deny that this doctrine of 

 Homologies has been established as a strictly sci- 

 entific truth ? There is a sense, of course, in which 

 all Knowledge and all Science belongs to Metaphy- 

 sics. Mere classification, which is the basis of all 

 Science, what is it but the marshalling of physical 

 facts in an Ideal Order — an arrangement of them 

 according to the relation which they bear to the 

 laws of Thought ? But this does not constitute as 

 a branch of Metaphysics, the division of animals 

 into Genera, and Families, and Orders. And what 

 relation can physical facts ever have to Thought so 

 directly cognisable or so susceptible of Demonstra- 

 tion as the relation of an animal organ to its pur- 

 pose and function in the animal economy ? Whe- 

 ther Purpose be the basis of all natural Order or 

 not is a separate question. It is at least one of 

 the facts of that Order. Combination for the ac- 

 complishment of Purpose therefore in particular 

 cases, such as the relation between the structure 

 of an Organ and its function, is not merely a 

 safe conclusion of Philosophy, but an ascertained 

 rfact of Science. 



The universal prevalence of this idea in Nature 



