Marsilio Ficino’s Platonic Theology, Volume I

74The Platonists hold, as we have said, that not only the heavens but also the elements are alive. They see every sphere of the world, together with the many composite bodies attached to them, moved by an inward motion without any external impulse; they therefore judge that souls dwell within them. If someone asks about the ascent and descent of the elements and of composite bodies, the Platonists will reply that this too is brought about by a soul—by the soul, I mean, of each thing's own sphere. Just as a magnet draws iron, that soul calls the particles of its sphere back to itself. Hence the motion of a stone falling from a height grows swifter as it approaches the earth; and likewise the rising motion of flame grows more impetuous as it draws nearer to heaven. For the soul of a sphere seizes more powerfully what is close at hand, while the soul of the world also draws it toward the same place. If men saw the iron move but did not see the magnet, they would think the iron moved by itself even while the magnet was drawing it. So now, those who do not understand the souls of the spheres believe that every little body moves of itself.

75Yet no craftsman's mind moves either its own members or its instruments with the precision with which those little bodies are moved in the world. Those bodies must therefore be moved and guided not merely by an inert quality, but also by an artful nature. Properly natural motion in the elements is motion that does not pass beyond the bounds of nature and of natural place: a perpetual circuit in its own place and natural sphere, closely answering to its own shape. Fire and air circle as the moon does, as the revolution of comets shows. Water circles by continually flowing back. If the earth moved, as Egelias held, it would move in a circle; yet, as most maintain, it remains at rest throughout its surface. Its parts do, in a certain fashion, circle the center of the world, insofar as they press one another on every side about that center with an everlasting effort. Ascent or descent, however, is not strictly a natural motion, but a swift restoration along a straight line to natural place and natural motion.