The essential quality of a work of art is harmony. In sculptural works harmony derives from the light that gives it relief and decorates it.
Beauty is the resplendence of the truth. Seeing as art is beauty, without truth there is no art.
To find truth one should know well the natural world.
It is essential, without any distortion whatsoever, to leave things in free asymmetry:
Scaled buildings, unequal bodies etc.
Symmetry belongs to the plain, and wishing to introduce it to the mountain is to deny its adaptation and character and obtain an inexpressive and costly coldness.
Plato argued school children should not be taught art, but only geometry, as art is always a misrepresentation of the real truth.
Republic: The imitator is a long way off the truth.
Socrates is reported by Xenophon in Memorabilia as asking:
Do your statues not have that sense of life because you closely imitate the forms of living beings?
Shouldn’t we also portray the threatening look in the eyes of warriors, shouldn’t we imitate the look of the conqueror flushed with success?
Indeed we should. In this way, then, the sculptor can depict the workings of the soul through external forms.
And so even a basket for carrying rubbish is thus a beautiful thing?
And a golden shield may be an ugly thing, if the former is well suited and the latter ill suited to their respective purposes
From Umberto Eco on Beauty.