Theaetetus

SO. for each alone by itself can only be named, and no qualification can be added, neither that it is nor that it is not, for that would at once be adding to it existence or non-existence, whereas we must add nothing to it, if we are to speak of that itself alone. Indeed, not even itself or that or each or alone or this or anything else of the sort, of which there are many, must be added; for these are prevalent terms which are added to all things indiscriminately and are different from the things to which they are added; but if it were possible to explain an element, and it admitted of a rational explanation of its own, it would have to be explained apart from everything else. But in fact none of the primal elements can be expressed by reason; they can only be named, for they have only a name; but the things composed of these are themselves complex, and so their names are complex and form a rational explanation; for the combination of names is the essence of reasoning. Thus the elements are not objects of reason or of knowledge, but only of perception, whereas the combinations of them are objects of knowledge and expression and true opinion. When therefore a man acquires without reasoning the true opinion about anything, his mind has the truth about it, but has no knowledge; for he who cannot give and receive a rational explanation of a thing is without knowledge of it; but when he has acquired also a rational explanation he may possibly have become all that I have said and may now be perfect in knowledge. Is that the version of the dream you have heard, or is it different?

THEAET. That was it exactly.

SOC. Are you satisfied, then, and do you state it in this way, that true opinion accompanied by reason is knowledge?

THEAET. Precisely.

SOC. Can it be, Theaetetus, that we now, in this casual manner, have found out on this day what many wise men have long been seeking and have grown grey in the search?

THEAET. I, at any rate, Socrates, think our present statement is good.

SOC. Probably this particular statement is so; for what knowledge could there still be apart from reason and right opinion? One point, however, in what has been said is unsatisfactory to me.

THEAET. What point?

SOC. Just that which seems to be the cleverest; the assertion that the elements are unknowable and the class of combinations is knowable.

THEAET. Is that not right?

SOC. We are sure to find out, for we have as hostages the examples which he who said all this used in his argument.

THEAET. What examples?

SOC. The elements in writing, the letters of the alphabet, and their combinations, the syllables; or do you think the author of the statements we are discussing had something else in view?

THEAET. No; those are what he had in view.