Full Idea
There's no other medium in which someone who uses the appropriate faculty to see beauty can give birth to true goodness, instead of phantom goodness, because it is truth rather than illusion whose company he is in.
Gist of Idea
Perceiving true beauty leads to truth, and hence to goodness
Source
Plato (The Symposium [c.373 BCE], 212a)
A Reaction
This is the core of platonism, where the faculties of love and intellect achieve the truth about beauty, which immediately leads to goodness. I wish I could find a modern way that is less mystical to express this thought. Beauty, truth and goodness.
Book Reference
Plato: 'Symposium', ed/tr. Waterfield,Robin [OUP 1994], p.56