This was not necessarily seen as magic. Al-Kindi’s theory of stellar rays was considered a plausible, secular, scientific theory. When Gemma Frisius lectured on his Theory of the Planets, this is probably what he was lecturing about. Now, don’t take this as a hit against al-Kindi, or Gemma, or Gerardus. This was not a dumb idea, and these men were not dumb for thinking this. In fact, it was a fairly rational explanation for many of the natural phenomena these men were observing. That very same book that gave us Stellar Ray theory, effectively, and accurately, describes the nature of light itself, 1100 years before Max Planck discovered the photon. al-Kindi was not a stupid man. The philosophers of the past, for all their strange thoughts, were not stupid. They just live in history, and are subject to our judgment. You and I will live there one day. And history makes fools of us all. Stay humble. 

ALT

Gennady Aygi, tr. by Peter France, from “The People Are a Temple.” [ID in alt text]