Shelley is a revolutionary because he is a visionary, and his finest poems underpin the anti-tyrannical stance with an idealism which continually emphasizes the importance of making a new world of love. In the communication of this, the finest poems are those in which Shelley can find the classical or mythological framework which can control his complex, teeming connections between the ultimate aspirations and the immediate duty: the greatest example is Prometheus Unbound. Shelley employs the device of the Fairy's taking Ianthe's spirit into a world of vision in order to perceive a reality which is beyond the normal earthly sense-impressions. Plato, like Shelley, was a natural myth-maker, inventing such poetic myths as the description of the prisoners in the cave to explain the human condition. Much of the splendid effect of Shelley's drama depends upon its combination of an Aeschylean simplicity with a lyric impulse, especially in the second half of the work.