4479. The sirens, moreover, are such that no man who has once esteemed adulteries and such things as nothing, and has thus involved himself as to the thought in the companionship of those who are such in the other life, can ever escape being held captive by them to the end of his life; for they bend the least things of the thoughts in innumerable ways, and make them delightful, and thus operate for the destruction of the man. This is yet more the case at the present time, when this crew is greatly increased, and also because evil spirits are tolerated in the world of spirits. Wherefore let men beware of actual evils; in this way only can anyone at last abstain from them; for actualities bring on habits, and put on a kind of nature, as happens with those who have exercised themselves in thefts, and thus evils are increased, together with their delights, and men are carried away by an increasing number of sirens, like a piece of wood in a rapid stream. Such a wandering crowd of sirens is multiplied at the present day far beyond their numbers in former times.