In a significant essay on Platonic philosophy, R. J. O’Connell highlights one of the most interesting and problematic aspects of the identification of the good and the beautiful in the Greek philosophical tradition :

‘It is a truism to say that, for the Greek mind, the good and the beautiful
(Kalokagathon) are at one , just as the evil and the ugly are. Use these terms
in their moral sense, however, and the gigantic act of ‘belief’ implied in that
equivalence becomes more evident.’

In an important section of his Symposium and in other dialogues such as the Phaedrus, Plato’s sense of the moral beauty of an act which had to take precedence over any questions of its advantageousness advanced Greek thought into a new realm of moral awareness – one that had begun to take seriously the issue of moral beauty as such. For Plato the act of belief that the beautiful and the good would coincide, still remained an act of faith, but a faith that was now grounded on a more robust realism. When the two forces of utility and virtue did not apparently or immediately coincide, then the precedence was unquestioningly given to the moral beauty of an act. Knowing that this preference could only be sustained on the ground of an enduring fundamental trust that however difficult the resolution might be, nevertheless the good and the true must be ultimately one, Plato held that the perception of this ultimate unity was a call to an ascending purification of perception, one that was religiously inspired and indeed no less than the transcendental imperative. Such an idea was one of the great forward leaps in the history of human thought and, even for this insight alone, justified the sense entertained by several of the fathers (and certainly some of the church’s iconographers who delighted in iconically depicting Plato on the church walls as a precursor of the Gospel) that here was a tradition of thought and belief that, like the Jewish lawyer, was ‘not far from the Kingdom of God’.

Plato added more, he understood that such a purified perception, frequently running against the current of human needs and self-referent desires, needed a dynamic motivating force to realise it, and , accordingly, posited love as the supreme virtue , or force, that gave the moral aesthetic sense its transcendent dynamic. In his Symposium he attributes the key role of teacher of these mysteries to the ‘stranger of Mantinea’, the priestess Diotima. In and through her initiations Plato intimates the profoundly religious character of his insight that the person who habitually prefers beauty is thereby increasingly led to an ascent to the Supremely Beautiful.

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