SOCRATES: Is there not an absurdity in arguing that there is nothing good or noble in the body, or in anything else, but that good is in the soul only, and that the only good of the soul is pleasure; and that courage or temperance or understanding, or any other good of the soul, is not really a good?--and is there not yet a further absurdity in our being compelled to say that he who has a feeling of pain and not of pleasure is bad at the time when he is suffering pain, even though he be the best of men; and again, that he who has a feeling of pleasure, in so far as he is pleased at the time when he is pleased, in that degree excels in virtue? PROTARCHUS: Nothing, Socrates, can be more irrational than all this. SOCRATES: And now, having subjected pleasure to every sort of test, let us not appear to be too sparing of mind and knowledge: let us ring their metal bravely, and see if there be unsoundness in any part, until we have found out what in them is of the purest nature; and then the truest elements both of pleasure and knowledge may be brought up for judgment. PROTARCHUS: Right. SOCRATES: Knowledge has two parts,--the one productive, and the other educational? PROTARCHUS: True. SOCRATES: And in the productive or handicraft arts, is not one part more akin to knowledge, and the other less; and may not the one part be regarded as the pure, and the other as the impure? PROTARCHUS: Certainly. SOCRATES: Let us separate the superior or dominant elements in each of them. PROTARCHUS: What are they, and how do you separate them? SOCRATES: I mean to say, that if arithmetic, mensuration, and weighing be taken away from any art, that which remains will not be much. PROTARCHUS: Not much, certainly. SOCRATES: The rest will be only conjecture, and the better use of the senses which is given by experience and practice, in addition to a certain power of guessing, which is commonly called art, and is perfected by attention and pains. PROTARCHUS: Nothing more, assuredly. SOCRATES: Music, for instance, is full of this empiricism; for sounds are harmonized, not by measure, but by skilful conjecture; the music of the flute is always trying to guess the pitch of each vibrating note, and is therefore mixed up with much that is doubtful and has little which is certain. PROTARCHUS: Most true. SOCRATES: And the same will be found to hold good of medicine and husbandry and piloting and generalship. PROTARCHUS: Very true. SOCRATES: The art of the builder, on the other hand, which uses a number of measures and instruments, attains by their help to a greater degree of accuracy than the other arts. PROTARCHUS: How is that? SOCRATES: In ship-building and house-building, and in other branches of the art of carpentering, the builder has his rule, lathe, compass, line, and a most ingenious machine for straightening wood. PROTARCHUS: Very true, Socrates.