214 Natural-Historical Collections. 



too easily thought they could, by means of this rule, dispense with the necessity 

 of direct observation ; but it must be allowed that it has more frequently led to 

 useful discoveries, and that in all cases it has thrown an interest upon researches, 

 which without it would have been too dry. Socrates, we say, was the first who 

 exposed this principle, and he has even expressed his regret at not being suffi- 

 ciently acquainted with the natural sciences, to have frequent occasion of apply- 

 ing it to them. 



Socrates was bom in the year 409, and died in 499 before the Christian era, 

 three years after the Peloponesian war. He was contemporary with Pericles, 

 Alcibiades, Xenophon, and Hippocrates. 



The pupils of Socrates, after their master's death, left Athens, where they could 

 not remain without danger, and withdrew to Megara and some other cities, to 

 continue their philosophical labours there. They founded various schools, of 

 which those best known are the Cyrenaic school, the Megaric, and the Cynic, but 

 especially the Academic school, the influence of which has been so extensive. 



Antisthenes, the founder of the Cynic sect, held that the object of philosophy 

 was to teach man to find the true good, which he placed in virtue ; and he main- 

 tained that it could only be come at by keeping in subjection all the inclinations. 



The Cyrenaic sect, which was founded by Aristippus, maintained that the true 

 good was to be found by indulging the natural inclinations in a moderate degree. 



The Megaric sect proceeded in the footsteps of the Elean school, and lost it- 

 self in dialectic subtleties. 



The Academic sect was founded by Plato, the youngest of the disciple of So- 

 crates. Plato was only twenty -nine years old when his master died. After hav- 

 ing in vain tried to defend him, he retired to Megara, and then to Cyrene. Be- 

 ing desirous of applying the time of his exile to the acquisition of knowledge, he 

 resolved to travel, and went over to Egypt, where he became a pupil of the 

 priests, who, notwithstanding the state of degradation to which they had been re- 

 duced under Cambyses, still preserved some traces of their ancient science. From 

 tlience he passed to Magna Graecia, and studied in the school of the Pythago- 

 reans, under Timasus of Locres and Archytas of Tarentum. Before leaving Me- 

 gara, he had exercised himself in dialectics under Euclid, who, like himself, had 

 been a pupil of Socrates, but at a previous period. Thus when, on returning to 

 Athens, he opened a new school, he had drawn from those which already existed 

 all that could be useful to him for methodizing his doctrine, and presenting it in 

 an advantageous manner. 



The natural bent of Plato's mind led him to poetry and fiction more than to 

 the sciences of observation and calculation. From his connection with the Py- 

 thagoreans, however, he had retained a great respect for geometry, and was desi- 

 rous that it should serve as an introduction to philosophy. It is not always easy 

 to determine what are his real doctrines ; for he did not expose them in a didac- 

 tic manner. It may be supposed, however, that in his dialogues where he com- 

 monly introduces Socrates as interlocutor, he has placed his own opinions in the 

 mouth of his master. 



Plato, in most of his writings, engages in the study of the human faculties, 

 the formation of ideas, and the nature of the soul. Although he borrowed many 

 metaphysical ideas from Anaxagoras, the Pythagoreans, and even the Elean 

 scliool, the ground of his doctrine is yet new. He admits, for example, that the 

 general ideas in man are not formed by means of abstraction, but that they are a 

 remembrance of those which our mind possessed when it was united to the divine 

 mind, of which it is only an emanation. General ideas, therefore, pre-exist in 

 the divinity. At a certain time they penetrated matter, which was itself eternal, 

 and from this impr^nation results the soul of the world and the soul of all orga- 

 nized beings. 



It will be seen that witli such bases for his philosophy, Plato would necessarily 

 be led to an a prion system of pliysics and natural history, which would conse- 

 quently be very wide of truth. The results of his speculations on these matters 

 are exposed in the Timceua, a tr^tise which, although rather obscure, is interest- 



