[259] Now with the refutation of this is involved that of both the teacher and the learner; though they are just as much open to doubt on their own account. For either the expert artist teaches the expert, or the non-expert the non-expert, or the non-expert the expert, or the expert the non-expert. Now the expert does not teach the expert; for neither of them, qua expert, needs teaching. Nor does the non-expert teach the non-expert, any more than the blind can lead the blind. ¹ Nor the non-expert the expert, for it would be ridiculous.

[260] The only thing left is to say that the expert teaches the non-expert; and this, too, is a thing impossible. For it is declared to be wholly impossible that an expert artist should exist, since neither do we see anyone existing spontaneously and from birth as an expert, nor does anyone turn into an expert from being a non-expert. For either one lesson and one apprehension can make an expert of the non-expert or they cannot do so at all. ²

[261] But if one apprehension makes the non-expert an expert, it will be open to us to declare, firstly, that art is not a system of apprehensions; ³ for the man who knows nothing at all would be termed an expert if only he were taught a single lesson of art. And, secondly, should anyone assert that, as soon as a man who has acquired some principles of art and still needs one more, and because of this is non-expert, acquires also that one principle, he at once becomes an expert instead of a non-expert by means of one apprehension, he will be making a random assertion. ⁴

[262] For in the case of individual men we could not point to one who, being still a non-expert, will become an expert by acquiring one additional principle; for no one, to be sure, has such a command of the numeration of the principles of each art as to be able to say, by numbering off the known principles, how many are still needed to make up the full number of the principles of the art. So then the learning of one principle does not make the non-expert an expert.

[263] But if this is true, seeing that no one acquires all the principles of the arts at once, but each .one singly, if at all—this point also being granted by way of assumption—the man who is said to acquire the principles of the art one by one will not be termed an expert; for we recall the conclusion that the learning of one principle cannot make an expert of the non- expert. No one, then, becomes an expert from being a non-expert. Hence, on these grounds too, the expert artist appears to be non-existent. And therefore the teacher also.

[264] Neither can the so-called learner, if he is non- expert, learn and apprehend the principles of the art wherein he is non-expert. For just as the man who is blind from birth, in so far as he is blind, will not acquire perception of colours, nor, similarly, he who is deaf from birth, of sound, ⁵ so too the non-expert will not apprehend the principles of the art wherein he is non-expert. For should he do so the same man would be both expert and non-expert in the same things—non-expert since he is such by hypothesis, and expert since he has apprehension of the principles of the art. Hence, neither does the expert teach the non-expert.

[265] But if neither the expert teaches the expert, nor the non-expert the non- expert, nor the non-expert the expert, nor the expert the non-expert, and these are all the alternatives possible, then neither the teacher exists nor the taught.