127 But is their opinion preferable, who say that our souls, when they have passed out of these bodies, migrate into the bodies of beasts, or of various other living creatures? Philosophers, indeed, themselves are wont to argue that these are ridiculous fancies of poets, such as might be produced by draughts of the drugs of Circe; and they say that not so much they who are represented to have undergone such things, as the senses of those who have invented such tales are changed into the forms of various beasts as it were by Circe's cup. For what is so like a marvel as to believe that men could have been changed into the forms of beasts? How much greater a marvel, however, would it be that the soul which rules man should take on itself the nature of a beast so opposed to that of man, and being capable of reason should be able to pass over to an irrational animal, than that the form of the body should have been changed? You yourselves, who teach these things, destroy what you teach. For you have given up the production of these portentous conversions by means of magic incantations.
Source: On the Death of Satyrus (New Advent)