Yet he failed to recognize it as a blurred host of stars, placing it instead in the realm of things knowable only to God. Philoponus rejected still other Aristotalian errors. In Aristotle's thought, things move toward their affines, that is, toward objects possessing similar properties. Phrased more practically, this means air tends to rise. Earth will fall to rest with earth.
Celestial objects are in an etheric class all their own.
Nonsense, said John. Lift a shovelful of dirt and air rushes into the hole. Philoponus taught that light is a directional phenomenon. Rays are not projected from our eyes to the object, but they move from the object to our eyes. This now seems obvious, but to early thinkers, attempting to explain the conic spread of light, it did not.