The most characteristic side of Milton’s idealism, however, is revealed in his teaching of the doctrine of chastity as the purity of the soul. In the defence of his own life which he made in “An Apology for Smectymnuus,” he acknowledges an important debt in his education to the teaching of Platonic philosophy. “Thus, from the laureat fraternity of poets,” he says, “riper years and the ceaseless round of study and reading led me to the shady spaces of philosophy; but chiefly to the divine volumes of Plato, and his equal Xenophon: where, if I should tell ye what I learnt of chastity and love, I mean that which is truly so, whose charming cup is only virtue, which she bears in her hand to those who are worthy ... and how the first and chiefest office of love begins and ends in the soul, producing those happy twins of her divine generation, knowledge and virtue: with such abstracted sublimities as these, it might be worth your listening, readers, as I may one day hope to have ye in a still time, when there shall be no chiding.”[3] Milton was the only poet of his time who was able to conceive of chastity as an “abstracted sublimity,” known in and by the soul. In his treatment of this theme, there are two phases: one in which the enthusiasm of Milton asserts itself in a positive way, and the other a conviction of maturer experience, in which sin is explained negatively in its relation to the soul’s purity. The fundamental idea of Plato on which Milton built his doctrine of chastity is the one taught in the “Phædo,” that every experience of the soul gained through the medium of the senses tends to degrade the soul’s pure essence into the grosser, corporeal form of the body. “And were we not saying long ago,” says Socrates, “that the soul, when using the body as an instrument of perception, that is to say, when using the sense of sight or hearing or some other sense (for the meaning of perceiving through the body is perceiving through the senses)—were we not saying that the soul too is then dragged by the body into the region of the changeable, and wanders and is confused; the world spins round her, and she is like a drunkard, when she touches change?” (“Phædo,” 79.) This appears in the “Comus” in a modified form, and constitutes the basis for Milton’s conception of sin in “Paradise Lost.” In the masque the idea is plainly stated by the Elder Brother in his explanation of the doctrine of chastity; and its workings are seen in the effect of the magic potion of Comus upon all who drink it.