50 Baron Cuviei's Lectures on the Natural Sciences. 



had been the friend of one of them, of Critias. This connec- 

 tion, however, which the love of science alone had formed, never 

 induced the philosopher to deviate from the rule of conduct 

 which he had traced to himself, and at all times he had been as 

 impregnable to the suggestions of friendship as to threats or 

 violence. 



Socrates did not cultivate the physical sciences ; yet he con- 

 tributed more than any person to give them the direction 

 which they presently assumed, and it may be said that he paved 

 the way for Aristotle. The Eleatic School introduced at Athens 

 had there by its degeneration produced the sophists, who, by 

 dint of subtleties, had succeeded in throwing uncertainty over 

 the clearest notions. It was to combat them that Socrates 

 chiefly laboured. To force them to relinquish the subterfuges 

 to which they habitually had recourse, one of his chief means was 

 defining precisely the value of terms. In this manner he creat- 

 ed a rigorous language, and thus rendered an important sei*vice 

 to the positive sciences, by furnishing them with the instru- 

 ment which was indispensable to them. 



It is to Socrates that we owe the introduction of a very broad, 

 principle, by which the natural sciences have greatly benefited, 

 the principle oi final causes, or, as it is now called, conditions of 

 existence. He tells us himself that this idea was suggested to 

 liim by the reading of a work of Anaxagoras, on the intelligence 

 which has arranged the world. If the universe, thought he, is 

 the work of an intelligent being, all its parts must be in accord- 

 ance, and disposed so as to concur to a common end. There 

 results from this, that every organized being must be connected 

 with all the others by necessary relations, and, moreover, that 

 it must contain in itself all the conditions which may enable it 

 to perform the part assigned to it. 



The principle of final causes has sometimes led into error spe- 

 culative minds who have too easily believed^themselves, by means 

 of this rule, to be freed from the necessity of direct observation ; 

 yet, it must be allowed that it has still more frequently led to 

 useful discoveries ; and that, in all cases, it has thrown interest 

 upon researches which, without it, would have been very dry. 

 Socrates was the first who explained this principle, and he even 



