Body uses many instruments, soul uses body and parts, soul has been brought into being as the instrument of God. The excellence of an instrument is to imitate most closely the power which uses it, with all its own natural power, and to reproduce the effect of his essential thought, but to exhibit it, not pure and passionless and free from error, as it was in the creative artist, but with a large admixture of foreign element. For in itself it is invisible to us, but appearing 'other' and through another medium it is saturated with the nature of that medium. I pass over wax and gold and silver and copper, and all other varieties of moulded substance, which take on one common form of impressed likeness, but add to the copy each its distinct specialty. I pass over the myriad distortions of images and reflections from a single form in mirrors, plane, hollow, or convex. For nothing seems better to reproduce the type, no instrument more obediently to use its own nature, than the moon. Yet taking from the sun his bright and fiery rays, she does not transmit them so to us: mingled with herself they change colour and also take on a different power; the heat wholly disappeared, and the light fails from weakness before it reaches us. I think you know the saying found in Heraclitus, that 'the sovereign whose seat is at Delphi, speaks not, nor conceals, but signifies'. Take and add then to what is here so well said, the conception that the God of this place employs the Pythia for the hearing as the sun employs the moon for the seeing. He shows and reveals his own thoughts, but shows them mingled in their passage through a mortal body, and a soul which cannot remain at rest or present itself to the exciting power unexcited and inwardly composed, but which boils and surges and is involved in the stirrings and troublesome passions from within. As whirlpools do not keep a steady hold on bodies borne round and round, and also downwards, since an outer force carries them round, but they sink down of their own nature, so that there is a compound spiral movement, of a confused and distorted kind, even so what we call inspiration seems to be a mixture of two impulses, and the soul is stirred by two forces, one of which it is a passive recipient, one form its own nature. We see that inanimate and stationary bodies cannot be used or forced contrary to their own nature, that a cylinder cannot be moved as if it were a sphere or a cube, that a lyre cannot be played like a flute or a trumpet like a harp, but that the artistic use of a thing is no other than the natural use. Is it possible, then, that the animate and self-moving, which has both impulse and reason, can be treated in any other way than is agreeable to the habit, force or natural condition which is already existent within it? Can an unmusical mind be excited like a musical, or an unlettered mind be moved by literature, a mind untrained in reasoning, whether speculative or disciplinary, by logic? It is not to be spoken of.
Plutarch.