Several recent researchers discuss Plato's fallacies or reasoning flaws in his writings (see list of references). Yet what remains mostly unclear is why there are so many logical errors/fallacies/blunders in Plato's writings in the first place. The KEY QUESTION is: Did these many "flaws", e.g. in the Phaedo, escape Plato's attention? If so, the answer is obvious. If not, why he deliberately left them? Did he has a more mystical purpose in mind perhaps?
I've found two main answers to this question:
- Plato's dialogues are "almost intolerable ... so many blunders contained in them" for Bochenski who sees Plato as a second- or third-rate logician.
- Plato used fallacies deliberately to explain his arguments, e.g. R. Sprague.
One may think that the answer lies in between these two, but can you think of a more realistic philosophical, historical reason? After all, the Dialogues sparked approval and criticism for many centuries.
EDIT: Examples of fallacy:
Fallacy of equivocation in the Phaedo (Keyt): Socrates uses the dyad dead & not-dead. Then he equates not-dead with immortal (equivocation here), and finally with indestructible.
David Sachs A Fallacy in Plato's Republic The Philosophical Review. Vol. 72, No. 2 (Apr., 1963), pp. 141-158.
Raphael Demos, A Fallacy in Plato's Republic?The Philosophical Review Vol. 73, No. 3 (Jul., 1964), pp. 395-398
Keyt, D. (1963), The Fallacies in Phaedo 102a-107b. Phronesis: A Journal for Ancient Philosophy, 8, (1-2), 167-172.
Weller, C. (1995) Fallacies in the Phaedo Again. Archiv für Geschichte der Philosophie, 77 (2):121-134
Sprague, Rosamond (1963), Plato's use of fallacy,: a study of the Euthydemus and some other dialogues. BN.
Sartorius, Fallacy and Political Radicalism in Plato's republic. Canadian Journal of Philosophy. Volume 3, 1974 - Issue 3
Bochenski, I.M., Ancient Formal Logic, Amsterdam, 1951