I think most attentive readers of Plato's dialogues will find themselves in one of two camps: those who believe that Plato carried on the spirit of Socrates' philosophy, and those who believe he carried on the letter of Socrates' philosophy. There will certainly be some overlap here. Those who believe Plato carried on the spirit will acknowledge that dialogues such as the Apology are probably a fairly accurate account of what Socrates said on a particular occasion; those who believe he carried on the letter will have to acknowledge that dialogues such as the Parmenides could not be an accurate account of a historical encounter. A. E. Taylor is certainly more in the Socratic letter camp. I must admit that I'm more in the Socratic spirit camp.
My issue with the Socratic philosophical letter is that it makes Plato far too dependent on Socrates and accords to him very little philosophical originality. We are left with a philosopher that was little more than Socrates' stenographer. That, for me, pushes beyond the realm of credibility. Taylor balks at the notion that Plato would have used Socrates as a mouthpiece for anything he didn't really say. I agree we have to be careful here. I seriously doubt that Plato would have had Socrates say anything that would be at odds with what he knew Socrates' sensibilities were. But I don't believe the majority of the dialogues are anything approaching actual historical dialogic encounters. Taylor apparently thinks that Xenophon simply lifted his ideas from Plato for his own Socrates and gives his Memorabilia almost no credence. I can't accept that that is a reasonable appraisal. While Xenophon's Socrates and Plato's Socrates are indeed similar, one must acknowledge one fundamental difference: Xenophon's Socrates is on the whole far more concerned with ethics and isn't concerned with metaphysics hardly at all. Indeed, Xenophon goes out of his way to say that Socrates eschewed metaphysics. A way to reconcile these two versions might be to take a clue from Plato's dialogues that metaphysics were more an interest of Socrates' youth. This might explain why dialogues like the Timaeus and Parmenides largely utilize other speakers to put forth the Eleatic and Pythagorean ideas that they contain. Still, Plato's Socrates is undeniably a teacher of metaphysics aside from that. I don't doubt in the slightest that Socrates taught the essential features of the doctrine of forms/ideas, but I think Plato took these further than Socrates had. Socrates probably accepted that the forms were transcendent in some sense, but he was probably far more concerned with their practical application than their theoretical numinous features. I think Plato probably went further with Socrates' views on the soul (psyche) as well. I personally feel that the Phaedo is probably a fairly accurate account of what Socrates said on that particular occasion. The Phaedrus I don't think is. I find it interesting that Plato only mentions himself once in his dialogues, i.e. The Phaedo, and that is to stipulate that he was not present for this exchange. In my humble opinion, Plato did this to let the reader know that he is not pretending to always give historical testimony to what Socrates actually said. In his mind, that freed him to explore further some of the implied aspects of Socrates' philosophy concerning the things I just listed. When the ideas Plato wanted to explore were clearly more compatible with another school, he used other speakers that were affiliated with those schools. Taylor seems to accord to Plato originality in only very late dialogues like the Laws. I just can't go along with that. I admit that Aristotle does seem to confirm that some of the Platonic dialogues were expounding Socrates' own ideas. Often when he quotes them he attributes the thought to Socrates. Whether this is due to Aristotle receiving Plato's own confirmation that the very words were Socrates', or just the ideas, isn't manifest. Aristotle may have simply recognized that the dialogues used Socrates' as the mouthpiece for certain ideas and he respected Plato's desire to not take credit for them.
While some may see me accepting Xenophon's testimony as totally undermining Plato's, I see it more as a matter of according to Plato an originality of thought that is due him. Obviously, he was influenced by Socrates, but he was also influenced by the Eleatics, the Pluralists, the Orphics and the Pythagoreans as well. I would like to believe (and I believe there is some textual evidence for this) that Plato added something that was original to the preceding schools.
With the above being said, I think this was quite a good book. Some of Taylor's discussions I will certainly revisit in the future, namely, those on the Theaetetus, the Parmenides, the Republic, the Sophist, the Protagoras and his discussion on the early Academy. I recommend the book, but would encourage the reader to not accept Taylor's implicit attempt to marginalize Plato's originality.