The main teaching of Epicurus in respect of morals is contained in a letter to Men\nceus, which Diogenes Laërtius has preserved, and in which Epicurus expresses himself as follows: “The youth must neither be slow to study philosophy, nor must the old man feel it a burden, for no one is either too young or too old to study the health of his soul. We must therefore endeavour to find out wherein the happy life consists; the following are its elements: First, we must hold that God is a living Being, incorruptible and happy, as the general belief supposes Him to be; and that nothing is lacking to His incorruptibility nor to His happiness. But though the existence of the gods is known to be a fact, yet they are not such as the multitude suppose them to be. He is therefore not impious who discards his faith in the gods of the multitude, but he who applies to them the opinions entertained of them by the mass.” By these gods of Epicurus we can understand nothing else than the Holy, the Universal, in concrete form. The Stoics held more to the ordinary conception, without indeed giving much thought to the Being of God; with the Epicureans, on the other hand, the gods express an immediate Idea of the system. Epicurus says: “That which is holy and incorruptible has itself no trouble nor causes it to others; therefore it is unstirred by either anger or show of favour, for it is in weakness only that such find a place. The gods may be known by means of Reason; they consist partly in Number; others are the perfected type of man, which, owing to the similarity of the images, arises from the continuous confluence of like images on one and the same subject.”[163] The gods are thus the altogether general images which we receive into ourselves; and Cicero says (De Natura Deorum, 18, 38) that they come singly upon us in sleep. This general image, which is at the same time an anthropomorphic conception, is the same to which we give the name of Ideal, only that here the source assigned to it is the reiterated occurrence of images. The gods thus seem to Epicurus to be Ideals of the holy life; they are also existent things, consisting of the finest atoms; they are, however, pure souls, unmixed with any grosser element, and therefore exempt from toil and trouble and pain. Their self-enjoyment is wholly passive, as it must be if consistent, for action has always in it something alien, the opposition of itself and reality, and the toil and trouble which are involved in it really represent the aspect of consciousness of opposition rather than that of realization. The gods lead an existence of pure and passive self enjoyment, and trouble themselves not with the affairs of the world and of men. Epicurus goes on to say: “Men must pay reverence to the gods on account of the perfection of their nature and their surpassing holiness, not in order to gain from them some special good, or for the sake of this or that advantage,”[164] The manner in which Epicurus