In various places in his dialogues, Plato has it that “truth” is “saying what is.” This doesn’t just mean speaking statements that are abstractly the case, but actually making one’s speech match the things that are (or, being). In his Seventh Letter, Plato says that there are five components of knowledge. First are the three things by which knowledge is imparted: names, definitions, and images. Knowledge itself is the fourth thing, namely, “intelligence and right opinion” about the things to which the names, definitions, and images refer. The fifth thing is “the thing itself which is known and truly exists.” Knowledge is right opinion about being, and these things exist in the fifth thing, the soul. Knowledge of the soul is dependent on first having knowledge of the other four things (342a-e).
But here’s the problem: the first four things give only an inadequate understanding of the things in themselves (being), because the first four things are subject to changing conditions of time, history, culture, and other factors. Names of things are conventions; they can change over time. Likewise with definitions, which are “made up of names and verbal forms.” Images of the things are open to “refutation by the senses,” and all of this means that there is a difference between “that which has real being, and that which is only a quality.” This problem “fills, one may say, every man with puzzlement and perplexity” (342e-343c). This teaching is similar to what we find elsewhere in Socrates to the effect that the senses deceive a man and his only recourse for finding truth is to disregard the body: “when does the soul attain truth? – for in attempting to consider anything in company with the body she is obviously deceived,” and “thought is best when the mind is gathered into herself and none of these things trouble her…when she takes leave of the body, and has as little as possible to do with it, when she has no bodily sense or desire, but is aspiring after true being” (Phaedo 65).
At any rate, for Socrates, true knowledge, knowledge in the soul of the things that are (being) can only come to the man who has a “well-constituted mind” – only this sort of man can attain to “knowledge of that which is well-constituted.” For if a man is “ill-constituted by nature,” he will not be able to see the truth. Neither a general quickness of learning nor excellent power of memory can suffice for the ill-constituted man to learn the truth, for learning the truth is intimately tied up with a man’s moral character, and moral character, or matters of virtue and vice, “must be learnt, by complete and long and continuous study…[of] the true and the false about all that has real being” (343e-344b).
The end result of the virtuous man’s quest for knowledge will be that “After much effort, as names, definitions, sights, and other data of sense, are brought into contact and friction one with another, in the course of scrutiny and kindly testing by men who proceed by question and answer without ill will, with a sudden flash there shines forth understanding about every problem, and an intelligence whose efforts reach the furthest limits of human powers” (344b).
Now this is fascinating. Plato is not only saying that (1) true knowledge is knowledge of the things that really exist rather than of the things which inadequately try to circumscribe those things, but also that (2) true knowledge is a matter of first having ethical goodness. If you aren’t a good man, you can’t know truth because truth is of what is and what is is good. This reminds me of Richard Weaver’s famous statement that “If the will is wrong, reason only increases mischief.” More importantly, it seems remarkably similar to Scripture’s portrayal of knowledge being a matter of the fear of the Lord (Ps. 111:10) and of having a “spiritual” mind (1 Cor. 2:14). So I take it that if Scripture teaches that there is an antithesis involved in knowing truth, and that that antithesis is fundamentally ethical, then Plato is on this point in agreement with Scripture. Sure, he doesn’t equate being ethical with “fearing the Lord” nor with having “the mind of Christ,” but this is the sort of thing, surely, that prompted Augustine to say that with only a change of a few words and phrases Plato could have been a Christian.