‹‹‹ Vitr. 1.1.15 | Table of Contents | Vitr. 1.1.17 ›››
16The astronomer and musician delight in similar proportions, for the positions of the stars, which are quartile and trine, answer to a fourth and fifth in harmony. The same analogy holds in that branch of geometry which the Greeks call λόγος ὀπτικὸς: indeed, throughout the whole range of art, there are many incidents common to all. Practice alone can lead to excellence in any one: that architect, therefore, is sufficiently educated, whose general knowledge enables him to give his opinion on any branch when required to do so.
16Astronomers likewise have a common ground for discussion with musicians in the harmony of the stars and musical concords in tetrads and triads of the fourth and the fifth, and with geometricians in the subject of vision (in Greek λὁγος ὁπτικὁς); and in all other sciences many points, perhaps all, are common so far as the discussion of them is concerned. But the actual undertaking of works which are brought to perfection by the hand and its manipulation is the function of those who have been specially trained to deal with a single art. It appears, therefore, that he has done enough and to spare who in each subject possesses a fairly good knowledge of those parts, with their principles, which are indispensable for architecture, so that if he is required to pass judgement and to express approval in the case of those things or arts, he may not be found wanting.