Dört Kitap, Tetrabiblos

That a certain power is derived from the ethereal and eternal nature and is dispersed through the entire neighborhood of the earth, which is subject to change throughout. This power affects the primary elements located beneath the Moon, namely fire and air, which are encompassed and shifted by the movements of the ether. These, in turn, encompass and shift all other things: the earth and water, and the plants and animals within them. This fact would be most evident to everyone through just a few observations. For the Sun, together with the surrounding environment, is always somehow disposing everything on earth; not only through the changes of the yearly seasons, leading to the generation of animals, the fruitfulness of plants, the flowing of waters, and the transformations of bodies, but also through its daily cycles, heating, moistening, drying, and cooling in a regular order and in accordance with its positions relative to our zenith. The Moon also, as the body closest to the earth, bestows her influence upon terrestrial things; most things, both animate and inanimate, are sympathetic to her and change along with her. Rivers increase and decrease their flow according to her light; the seas turn their own tides with her rising and setting; and plants and animals, either in their entirety or in specific parts, wax and wane with her. Furthermore, the passages of the stars, both the fixed stars and the planets, create many signs in the surrounding environment, such as heatwaves, winds, and snowstorms, by which things on earth are appropriately disposed. Moreover, their aspects relative to one another, as their influences meet and mingle, produce many complex changes. While the power of the Sun prevails in the general regulation of quality, the other bodies assist or oppose it in particular ways.