But can you tell me of any other suitable study?
No, he said, not without thinking.
Motion, I said, has many forms, and not one only; two of them are obvious enough even to wits no better than ours; and there are others, as I imagine, which may be left to wiser persons.
But where are the two?
There is a second, I said, which is the counterpart of the one already named.
And what may that be?
The second, I said, would seem relatively to the ears to be what the first is to the eyes; for I conceive that as the eyes are designed to look up at the stars, so are the ears to hear harmonious motions; and these are sister sciences--as the Pythagoreans say, and we, Glaucon, agree with them?
Yes, he replied.
But this, I said, is a laborious study, and therefore we had better go and learn of them; and they will tell us whether there are any other applications of these sciences.

At the same time, we must not lose sight of our own higher object.
What is that?
There is a perfection which all knowledge ought to reach, and which our pupils ought also to attain, and not to fall short of, as I was saying that they did in astronomy.

For in the science of harmony, as you probably know, the same thing happens.

The teachers of harmony compare the sounds and consonances which are heard only, and their labour, like that of the astronomers, is in vain.
Yes, by heaven! he said; and 'tis as good as a play to hear them talking about their condensed notes, as they call them; they put their ears close alongside of the strings like persons catching a sound from their neighbour's wall--one set of them declaring that they distinguish an intermediate note and have found the least interval which should be the unit of measurement; the others insisting that the two sounds have passed into the same--either party setting their ears before their understanding.
You mean, I said, those gentlemen who tease and torture the strings and rack them on the pegs of the instrument: might carry on the metaphor and speak after their manner of the blows which the plectrum gives, and make accusations against the strings, both of backwardness and forwardness to sound; but this would be tedious, and therefore I will only say that these are not the men, and that I am referring to the Pythagoreans, of whom I was just now proposing to enquire about harmony.

For they too are in error, like the astronomers; they investigate the numbers of the harmonies which are heard, but they never attain to problems-that is to say, they never reach the natural harmonies of number, or reflect why some numbers are harmonious and others not.
That, he said, is a thing of more than mortal knowledge.
A thing, I replied, which I would rather call useful; that is, if sought after with a view to the beautiful and good; but if pursued in any other spirit, useless.