[6] “And when the angels of God saw the daughters of men that they were fair, they took to themselves wives from all, those whom they chose” (Gen. 6:2). It is Moses’ custom to give the name of angels to those whom other philosophers call demons (or spirits), souls that is which fly and hover in the air.
[7] And let no one suppose that what is here said is a myth. For the universe must needs be filled through and through with life, and each of its primary elementary divisions contains the forms of life which are akin and suited to it. The earth has the creatures of the land, the sea and the rivers those that live in water, fire the fire-born, which are said to be found especially in Macedonia, and heaven has the stars.
[8] For the stars are souls divine and without blemish throughout, and therefore as each of them is mind in its purest form, they move in the line most akin to mind—the circle.
And so the other element, the air, must needs be filled with living beings, though indeed they are invisible to us, since even the air itself is not visible to our senses.
[9] Yet the fact that our powers of vision are incapable of any perception of the forms of these souls is no reason why we should doubt that there are souls in the air, but they must be apprehended by the mind, that like may be discerned by like.
[10] Here is a further consideration. Do not all creatures of land and water live by air and breath? And is it not true, that when the air is plague-stricken, disastrous pestilences often arise, suggesting that air is the animating principle to all and each, while on the other hand, when it is free from taint and mischief, a state which is most often found when the north wind blows, these same creatures, inhaling as they do a purer atmosphere, tend ever to enjoy a more abundant and stronger vitality?
[11] Is it then reasonable to suppose that this element which has been the source of life to the others, the denizens of land and water, should itself be desert and destitute of living souls.? Nay, on the contrary, if all the other elements produced no animal life, it were still the proper function of the air to do what none other did and bring forth living beings, since to it the seeds of vitality have been committed through the special bounty of the Creator.