76 THE GREEK SCHOOL PHILOSOPHY. 



knowledge can exist, entertained the same opinions at a later period 

 also. When, afterwards, Socrates treated of moral Eiibjects, and gave 

 no attention to physics, but, in the subjects which he did discuss, 

 arrived at universal truths, and before any man, turned his thoughts 

 to definitions, Plato adopted similar doctrines on this subject also; 

 and construed them in this way, that these truths and definitions must 

 be applicable to something else, and not to sensible things : for it was 

 impossible, he conceived, that there should be a general common defi- 

 nition of any sensible object, since such were always in a state of 

 change. The things, then, which were the subjects of universal truths 

 he called Ideas; and held that objects of sense had their names 

 according to Ideas and after them ; so that things participated in that 

 Idea which had the same name as was applied to them." 



In agreement with this, we find the opinions suggested in the 

 Parmenides of Plato, the dialogue which is considered by many to 

 contain the most decided exposition of the doctrine of Ideas. In this 

 dialogue, Parmenides is made to say to Socrates, then a young man, 26 

 " O Socrates, philosophy has not yet claimed you for her own, as, in 

 my judgment, she will claim you, and you will not dishonor her. As 

 yet, like a young man as you are, you look to the opinions of men. 

 But tell me this : it appears to you, as you say, that there are certain 

 Kinds or Ideas (sidy) of which things partake and receive applications 

 according to that of which they partake : thus those things which par- 

 take of Likeness are called like ; those things which partake of Great- 

 ness are called great ; those things which partake of Beauty and Jus- 

 tice are called beautiful and just" To this Socrates assents. And in 

 another part of the dialogue he shows that these Ideas are not in- 

 cluded in our common knowledge, from whence he infers that they are 

 objects of the Divine mind. 



In the Phaedo the same opinion is maintained, and is summed up in 

 this way, by a reporter of the last conversation of Socrates, 27 g/vai <r 

 <rwv <wv, xa/ <TOOTWV r'aXXa jLnraXa/A/3avov-ra a-JTwv Twrwv rr/v 

 ' "tf^eiv ; " that each Kind has an existence, and that other 

 things partake of these Kinds, and are called according to the Kind of 

 which they partake." 



The inference drawn from this view was, that in order to obtain 

 true and certain knowledge, men must elevate themselves, as much as 

 possible, to these Ideas of the qualities which they have to consider : 



26 ParmeniJ. p. 131. " phaeJo, p. 102. 



