Aristotle's Metaphysics was given wider exposure in Western Europe after the Fourth Crusade and brought many "new" ideas to scholars. Aristotle was firm in his belief that nothing in nature happened without influence from the "supercelestial bodies," the perfect objects (sun, planets, stars) that were outside the sphere of the Moon.
A commentator on an early edition of Metaphysics expresses it this way:
...the generation of the elements and their parts is ordered and conserved through the motion of the supercelestial bodies, and through the motion of the elements which cooperate in a general way in the production of mixtures.
There was the idea that the human form was a mirror or analog of the universe, and there were correlations between the parts of the body and the constellations and planets. This idea was so fundamental that it lasted through the Renaissance. Even as late as 1697, John Case’s The Angelical Guide Shewing Men and Women their Lott or Chance, in this Elementary Life could show (see illustration):
...a circle with astrological figures and notations surrounds an oval containing a set of illustrations of the developing fetus ... The image is accompanied by an English translation of Kerckring’s notes on the figures, which describe the age of the embryos and the anatomical parts, but no mention is made by Case of the astrological surround, or the four cherubs in the corners. The image shows how easy it was to combine new anatomical findings with old astrological systems — they did not even need to be mentioned. [source]
So the fetus develops with the help of celestial influences, not just as a purely biological process. But what happens at the end of gestation? I think we need to look at midwifery next.
