From, A History of Greek Philosophy, vol. IV, Plato: the man and his dialogues, earlier period,
Cambridge University Press, 19896, pp. 8-38.
(2) PHILOSOPHICAL INFLUENCES
LATO did not think in an intellectual vacuum. Some of his profoundest and most original ideas resulted from the attempt to solve problems bequeathed by his predecessors, in whom he took the liveliest interest. Aristotle speaks of Plato’s philosophy as resembling the Pythagorean, but with certain features of its own. This is in the first book of the Metaphysics, where he is discussing the contributions made by previous philosophers to his own doctrine of ‘causes’, among which he counts the Platonic theory of Forms. Its distinctive character, he says, it owed, first; to early reflection on the Heraclitean view that the whole sensible world is in constant flux and cannot therefore be the object of knowledge. Impressed with this, Plato listened to Socrates who had abandoned the study of nature for ethics but in that field was seeking the universal and directing attention to the importance οf definition. Both views seemed to Plato right, and to reconcile them he supposed that the definitions which Socrates demanded must apply to non-sensible realities; for he thought it impossible that the common definition could belong to anything in the sensible world, since such things were always changing. ‘Realities of this kind’, continues Aristotle, ‘he called Forms [in Greek ideai, whence our ‘theory of Ideas’], and he said that sensible things existed apart from them and were named after them.’ Aristotle then goes on to make comparisons with Pythagoreanism whose accuracy is controversial. Ι mention the passage now only to make the point that besides what we can learn from the dialogues themselves there is also external evidence for the influence of other philosophers on Plato’s mind which may be worth examining and assessing. For the Pythagoreans we know also of the personal ties with Archytas and others which he formed and maintained on his visits to the West.
A Day in Old Athens * A Short History of Greek Philosophy
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