In the second half of the thirteenth century, St. Thomas Aquinas
modified the ancient cosmology of Aristotle so that it was consistent
with church dogma, and established it as the principal cosmology of the
Western Christian church.
The resulting Aristotelian-Thomistic cosmology may be summarized as follows. The Earth is stationary at the center of the cosmos. It is surrounded by nine celestial spheres (see figure). Moving out from the Earth, the first seven correspond to the then-known "planets" ("wanderers") in order of decreasing apparent speed (Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn). The eighth sphere corresponds to the fixed stars (that is, the constellations), which all rotate together. The ninth is the "crystalline sphere," which is sometimes identified with the tenth sphere, or Primum Mobile (Prime Mover), which imparts motion to all the inner spheres (except the Earth, which does not move).
These nine (or ten) spheres are all material, that is, subject to the laws of physics as Aristotelians understood them. Outside of the material universe was the Empyreum, where God, the angels, and the elect dwelt; this was conceived as a realm outside of time and space and therefore not subject to physical law. Thus, we have a cosmos correlated with a value hierarchy: from eternal God on high, we descend through the pristine and regularly rotating spheres of the Prime Mover and fixed stars, down through the spheres of the (somewhat erratically) wandering planets, to our Earth, a realm of generation and corruption and a battleground of good and evil. Hell, of course, was placed at the center of the Earth. Thus the universe was diabolicentric as well as geocentric, with an implication that the earth is irremediably tainted by evil. In particular, there was a qualitative distinction between the superior and orderly heavens and the imperfect and inferior Earthly realm.
This view of the universe was consistent the Aristotelian theory of form and matter. According to it, matter, as the primary stuff of the physical universe, is unformed and possesses no qualities of its own. It is rather the neutral ground in which qualities and properties may inhere. Since it is formless and propertyless, it is fundamentally chaotic and irrational. (This featureless substrate is sometimes called prime matter — prima materia — to distinguish it from the ordinary matter we see around us.)
On the other hand, the world derives its orderliness from abstract,
eternal Forms or Ideas (often understood as ideas in the mind of
God). It is these Forms that impart definite qualities or
properties to prime matter, and that govern orderly change in the
material realm. Thus, the eternal, unchanging Forms are the
source of order and rationality in the universe. Things in the
universe are ordered, rational, and comprehensible to the extent that
governing Form dominates the recalcitrant Matter in them.
We may see these degrees of order in the cosmos as a whole, for the eternal, unchanging Forms or Ideas reside in the mind of God in the Empyreum, a realm of pure Form. Via the Prime Mover, these Forms govern the very ordered rotation of the starry heavens, and the somewhat more erratic motion of the planets. The celestial bodies exhibit orderly motion because they are composed of a subtle, spiritual, aetherial matter. Earthly things, in contrast, are composed of four grosser elements (earth, water, air, fire), the matter of which is less conformable to the eternal, divine Ideas. Therefore, earthly processes are less ordered, more imperfect, and more chaotic than those in the heavens. Since earthly things are resistant to the eternal Forms, they are impermanent, and so all things on earth "come to be and pass away" (generation and corruption). In general, everything in Nature is considered to be an inevitably imperfect mixture of a rational formal component and an irrational material component.
The Aristotelian-Thomistic cosmology is correlated with a view of women.
Aristotelians explained sexual reproduction in terms of form and
matter. Since the foetus grew (increased materially) in the
mother's womb, and was nourished by the mother both before and after
birth, the mother was understood to provide the matter of the
baby. (Here the etymological roots of mater, materia, matrix
may be noted.) On the other hand, since the child resembles the
father, and since the volume of semen is small, it was supposed that
the father provides the form of the child. (The fact that the
child also resembles the mother was either ignored or accounted for in
other ways.) There is, of course, an element of truth in this
account, for the sole function of the sperm is to transport the DNA
encoding the genes — the genetic form — of the father.
Also, the mother, not the father, provides the matter by which the
foetus grows. However, it is incorrect in that it ignores the
fact that the mother also contributes form (via her DNA) to the child.
Another implication of the Aristotelian theory follows from the contrast between, on one hand, the forms or ideas, which are associated with the mind and rationality, as a source of purposeful thought, free will, and action, and, on the other, gross matter, associated with the body as the cause of irrationality and disorder. Thus the father is the source of the child's immortal soul, whereas the mother merely provides the corruptible body. (In accord with this view, menstrual fluid was considered defective semen, lacking soul.) Therefore, according to the common dualistic assumptions of Western thought, the father contributes the more important (theologically, the only important) part of the child.
Ideally, according to Aristotle, a male child would result from conception, but if the matter (provided by the mother) were especially resistant to the human form imparted by the father, a female child would result (which was considered, therefore, an incompletely formed male).
The Aristotelians held that form does not desire itself (or anything else), since it is not defective, but that matter is inherently incomplete, and so it naturally seeks form, in order to become complete and, insofar as it is possible for material things, perfect. Thus there is a natural movement or process by which each body seeks its own form.
Not coincidentally, Aristotle compared matter seeking form with a woman's desire for man. (It is worth noting that from antiquity to early modern times, it was widely believed that women were more interested in sex than men.) On the one hand, this view of female sexuality contributed to church doctrine according to which Eve was responsible for the Fall in the Garden of Eden, and a continuing source of temptation for man (considered as the more spiritual of the sexes). On the other, this seeking after form was considered the source of human striving after the divine (often expressed in terms of erotic desire); the Christian version was the Mother Church's devotion to God the Father.
The Aristotelian-Thomistic view of reality had implications for male and female psychology. Since in man, the domination of matter by form is more complete than in woman, by nature man is more rational, self-controlled, and spiritual, focused upward on heaven, while woman is more irrational, emotional, and lustful, focused downward on the body. This implies that man is superior to women in the faculties considered most important in politics and economics, and that women are best treated as overgrown children. (The implication may go in both directions: The assumed inferiority of women may have reinforced those philosophical beliefs that implied it; cf Hillman, Myth of Analysis, Pt. 3.)
From the foregoing, it is not at all hard to understand why Aristotle said that the Earth is female whereas the heavens are male (Gen. An. 716a). Of course, this built upon ancient mythological traditions in which earth goddesses (e.g., Gaia) are female, and the chief sky god is male (e.g., Zeus, Jupiter). Further, in both Greek and Latin the word for Nature, that is, the mixed realm of form and matter beneath the eternal and divine Empyreum, is a feminine noun (Lat. Natura, Grk. Physis). Thus we still speak of "Mother Nature."
And so we discover an important connection between how women are viewed and how Nature is viewed, and we will find corresponding correlations between how a society treats women and how it treats nature.