Shakespeare’s debt to Plato is often seen as not much more than an acquaintance with the meaning of ‘substance’ and ‘shadow’, relating to ‘ideal’ and ‘real’. A few wider explorations have been made, and more importantly W. H. Auden took the view that ‘the primary experience – complicated as it became later – out of which the sonnets to the friend spring was a mystical one’, of which ‘the classic descriptions . . . are to be found in Plato’s Symposium, Dante’s La Vita Nuova and some of these sonnets’. G. Wilson Knight also referred to the Symposium in The Mutual Flame. I return to Auden’s view later.

Platonic allusions are not prominent in the whole of the Sonnets, which are often the thoughts and feelings of a lover like other lovers, who protests his love, doubts his worthiness, denounces infidelity, is reconciled. There are, however, occasionally surprising phrases: the friend is ‘the grave where buried love doth live’ (31.9), he will ‘pace forth’ against death (55.10), he is ‘a God in Love’ (110.12), the poet ‘hallows’ his name, as though in the Lord’s Prayer (108.8). And there are close resemblances to a passage in the Symposium which speaks of a vision of universal love.

Shakespeare could have read the Symposium in Ficino’s Latin translation, and have discussed it with Ben Jonson, who owned a copy. It takes the form of a banquet, in which each of the speakers hold forth on the nature of Love, the most important being the wise woman Diotima, as reported by Socrates. Diotima denies that Love is merely love between human beings: it ‘includes every kind of longing for happiness and for the good’. It is found not only in poetry, but in business, athletics, philosophy.