  Maimonides recognizes (GP 2.24) that his argument does not constitute a demonstration. Just because science cannot explain something now, it does not follow that it will never be able to explain it. As he himself admits, science can and does make progress. But in the case of the heavenly bodies, he thought progress very unlikely. Because they too far away to make close observations, and too high in rank, we can only rely on inferences based on accidental qualities size, speed, and direction. As long as this is true, we will never know their essential natures and will never be able to support claims of necessity. As long as this is true, creation, though not demonstrated, will always be preferable to eternity.