In the middle dialogues, Socrates introduces theories:
• Theory of Recollection
• Theory of Forms
• Tripartite Theory of the Soul
• Theory of Justice
These "theories," as they are traditionally called, are not worked out in detail. Further, it should not be thought that Plato endorses them. Plato does not appear as a character in his dialogues. So it is difficult to know what he beliefs with respect to these theories. It seems natural, though, to think that he introduces them as possible solutions to problems he has uncovered in thinking about Socrates and the love of wisdom.
The Theory of Recollection
"Can you tell me, Socrates," asks Meno in the first line of the dialogue (Meno 70a), "whether virtue (ἀρετή) can be taught, or is acquired by practice, not teaching? Or if neither by practice nor by learning, whether it comes to mankind by nature or in some other way?"
The Meno opens differently than the Euthyphro. Euthyphro made assertion that prompted Socrates to ask for a definition. Meno asks Socrates a question about virtue: how human beings acquire it. Socrates jokes that Meno is from a place with wisdom because in Athens no one knows what virtue is, let alone how it is acquired. Socrates says that he shares in this lack of wisdom and that, further, he has never come across anyone who knows what virtue is. Meno is surprised that Socrates did learn what virtue is from Gorgias when he visited Athens. Socrates says, in reply, that maybe Gorgias did know, but that since he is not present, Meno himself should say what virtue is so that Socrates will meet with the good fortune of no longer having to say that he has never come across anyone who knows what virtue is. Meno tries to enlighten Socrates, but unlike interlocutors in previous dialogues devoted to a search for a definition, Meno has considerable trouble providing the right sort of answer to the "What is virtue?" question, and eventually Meno argues that the question is unanswerable.
To disarm the argument, Socrates introduces what has come to be known as the Theory of Recollection.
Socrates asks one of Meno's attendants some questions about how to double the area of the square ABCD. The attendant has not been taught geometry but finds his way to the answer with the help of Socrates' questioning. Socrates gives this questioning and answering as an instance of the more general phenomenon of "recollection," and he takes it to show that his questioning is not unanswerable and that Meno should stop arguing eristically.
"Without anyone having taught him, and only through questions, he will understand,
recovering the knowledge (ἐπιστήμην) out of himself?
And is not this recovery of knowledge, in himself and by himself, recollection?
Certainly" (Meno 85d).
The Theory of Recollection in the Phaedo
"When people are questioned, if you put the questions well, they answer correctly of themselves about everything; and yet if they had not within them some knowledge (ἐπιστήμη) and right reason, they could not do this" (Phaedo 73a).
"We say there is such a thing as equality (ἴσον). I do not mean one piece of wood equal to another,
or one stone to another, or anything of that sort, but something beyond that--the equal itself (αὐτὸ τὸ ἴσον).
Shall we say there is such a thing, or not?
We shall say that there is most decidedly Socrates.
And do we know what it is?
Whence did we come upon the knowledge of it? Was it not from the things we were just speaking of, by seeing equal pieces of wood or stones or other things, on the occasion of them that equal was in thought (ἐνενοήσαμεν), it being different from them? ... It is on the occasion of those equals, different as they are from that equal, that you have thought and come upon knowledge (ἐπιστήμην) of it?
That is perfectly true (Phaedo 74a-c).
Two Theses in the Theory of Recollection
The Theory of Recollection can be understood to consist of two thesis: an epistemological thesis and an ontological thesis.
The epistemological thesis is a form of rationalism. According to the thesis, some knowledge is an essential part of "reason" and the human soul. This knowledge cannot be eliminated in eliminating inconsistency. It is a structural feature of the human soul. The ontological thesis is about the existence of the soul and its relation to the body. According to the thesis, the soul is a persistent object whose existence is not contingent on the body. The soul exists before entering a body and will continue to exist after leaving the body.
The Beginning of an Explanation
Plato does not call attention to the fact, but he appears to have Socrates introduce the Theory of Recollection as a possible solution to some of the puzzles about the love of wisdom that Plato himself noticed when he was trying to understand Socrates. The suggestion in the early dialogues is that a human being can transform himself so that he possesses wisdom about ethical matters if he eliminates his confusion about what is good and what is bad. The idea seems to be that a human being eliminates his confusion by eliminating inconsistency in his beliefs. This method assumes that the problem is false belief, not the absence of knowledge, that the knowledge itself is present in the soul all along, and that this knowledge is not eliminated in the elimination of inconsistency.
The Theory of Recollection suggests the beginning of a way to make sense of this method. According to the theory, some knowledge belongs to "reason." It is not acquired in "experience." Instead, this knowledge is an essential part of the human soul. It cannot be lost but only obscured by false beliefs acquired in experience. When the soul enters the body, because this is traumatic, the soul forgets itself and its interests. In its confusion, the soul takes on the concerns of the body and in the process acquires the false beliefs that prevent one from making the right choices in life.
"Socrates' method of elenctic dialectic turns on consistency as the crucial feature to be preserved. Not only is inconsistency treated as a criterion for lack of knowledge or wisdom, it also seems to be assumed that the progressive elimination of inconsistency will lead to knowledge or wisdom. This presupposes that deep down we do have a basic knowledge at least of what matters, that we are just very confused, because we have also acquired lots of false beliefs incompatible with this basic knowledge. I take it that in Plato this assumption at times takes the form of the doctrine of recollection, whereas in Stoicism it is supposed to be captured by the theory of common notions and the common sense based on them. Unable to get rid of these notions and the knowledge of the world they embody, the only way to become consistent is to eliminate the false beliefs which stand in the way of wisdom." (Michael Frede, "On the Stoic Conception of the Good," 83.)
The fundamental problem remains
Although the Theory of Recollection provides the beginning of a way to make sense of the question-and-answer method, it does not prove a clear answer to all the questions about Socrates and his love of wisdom. In neither the Meno nor the Phaedo does Socrates explain exactly what knowledge belongs to "reason." The example he gives in the Meno involves the knowledge that constitutes geometrical concepts, but it is unclear that this knowledge is part of the wisdom that constitutes the virtue Socrates has in mind when, in the Apology, he talks about "wisdom and truth and the best state of [the] soul." The same is true for the knowledge of equality he mentions in the Phaedo. So although the Theory of Recollection may solve some problems, it leaves the fundamental problem without a clear solution. It remains difficult to see how eliminating inconsistency in belief with respect to ethical matters instills virtue in the soul and hence gives a human being the wisdom he needs to live a good life.
(Plato seems to provide some of the missing detail in subsequent dialogues the Theory of Forms, the Tripartite Theory of the Soul, and the Theory of Justice.)