Aristotle on Learning

Again, of all the things that come to us by nature we first acquire the potentiality and later exhibit the activity; but the virtues we get by first exercising them, as also happens in the case of the arts as well. For the things we have to learn before we can do them, we learn by doing them, e.g. men become builders by building and lyre-players by playing the lyre; so too we become just by doing just acts, temperate by doing temperate acts, brave by doing brave acts.

Aristotle, The Nicomachean Ethics