From, A History of Greek Philosophy, vol. IV, Plato: the man and his dialogues, earlier period,
Cambridge University Press, 19896, pp. 8-38.
The second question was answered by a development of the Pythagorean theory of reincarnation. As he explains in the Meno and Phaedrus, our souls are immortal but subject to a cycle of births in mortal bodies. They spend more time out of the body than in it, and in the disembodied state have the opportunity of seeing the Forms direct and clear. The experience of birth and contamination with the body causes forgetfulness, but the imperfect sensible approximations to the Forms may stimulate recollection of the Forms themselves. To see things - whether moral actions, circles and triangles or instances of physical beauty - which are all imperfect, could never of itself, in Plato’s view, implant in our minds the knowledge of perfection, nor could we abstract from them a standard by which to discriminate between them; but given that the vision preceded, they can start us on the road to its recovery.
In the Meno (vol. II, 232) Plato shows himself familiar with Empedocles’s theory of sensation, and the physiology of the Timaeus owes much to Empedocles’s ideas (217). Anaxagoras is criticized in the Phaedo (97b, pp. 274f.) and his discovery that the moon derives its light from the sun is mentioned in the Cratylus (409a, p. 306). Plato’s relations with Democritus are a fascinating but tantalizing subject, for he never mentions him, yet it is impossible to believe that he was not acquainted with his work, or that, if acquainted, he did not react strongly. There were curious similarities between them. Democritus called his ultimate realities ideai (vol. II, 395 n. 2), though for him this denoted the millions of irregularly-shaped, solid physical atoms. These ultimate realities were beyond the ‘bastard cognition’ of the senses, and, like the Platonic Forms, accessible only to thought (462). This made him a more dangerous foe, but a foe he remained, for he committed the ultimate blasphemy οf denying purpose in the universe and teaching a soulless, irrational mechanism. Plato must have had him in the forefront of his mind when in the Timaeus he put forward a mathematical atomism which could only be the work of Reason and in the Laws castigated atheistic philosophers who attributed the origin and nature of the cosmos to chance. Lastly, we have seen in the third volume how deeply Plato was involved in the arguments between Socrates and the views of the great fifth-century generation of Sophists. Protagoras, Gorgias and Hippias cross swords with him in dialogues called by their name, and together with Prodicus, Thrasymachus and others are frequently introduced or their views discussed. Ι have maintained that these characters appear as themselves, not as masks for Plato’s contemporaries, but he is hardly likely to have ignored these although, except for Isocrates, he does not mention them by name. He is fond of expressions like ‘a certain theory’, ‘some men’, ‘Ι have met many such’, ‘young men and late-learners’, ‘those who only believe what they can grasp with their hands’, ‘more refined intellects’ and so on. Whatever his motive for leaving them anonymous, it is very probable that these phrases conceal controversialists with whom he was personally acquainted. Names that have been suggested at various times include Antisthenes, Euclides and his Megarian friends, and Aristippus.
A Day in Old Athens * A Short History of Greek Philosophy
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