The Republic by Plato Part 3 Page 56

Yes, he said, I quite agree with you in thinking that our youth should be trained in music and on the grounds which you mention.

Just as in learning to read, I said, we were satisfied when we knew the letters of the alphabet, which are very few, in all their recurring sizes and combinations; not slighting them as unimportant whether they occupy a space large or small, but everywhere eager to make them out; and not thinking ourselves perfect in the art of reading until we recognise them wherever they are found:

True —

Or, as we recognise the reflection of letters in the water, or in a mirror, only when we know the letters themselves; the same art and study giving us the knowledge of both:

Exactly —