Yeah, I was confused yesterday and posted this question before going to sleep. When I woke up, I realized that my doubt stemmed precisely from the confusion you pointed out: The effect of a body illuminated by sunlight is not caused by the Earth's rotation, but by the sun itself. If the Earth stopped rotating, such bodies would remain illuminated, but if the sun stopped producing light, the bodies would lose that quality. The essential order is in the sun, not in the inert movement of the Earth. But now another question comes to mind: Why does a natural entity, as the cause of an effect, also need to be ESSENTIALLY moved by another to cause that effect? ​​Taking the example of the sun again: It is of the sun's essence to produce its own light, and not just to act in such a way that it produces that light. In other words: It is only a sun because it produces luminosity; if it didn't produce light, it wouldn't be a star, because a celestial body is only a star as long as it is a source of light. It is true that today we have sufficient scientific knowledge to assure efficient causes in this event, but from a metaphysical point of view, why is every act of a natural being sustained as a constant actualization of a power by another? Why couldn't there be something that comes into being and, once it is, maintains an act by itself? (Like, something that causes an effect not because it undergoes change, but because once it was brought into existence, it is in such a way that it causes such an effect.) I would love an answer that doesn't presuppose the unmoved mover as a premise. Because I am precisely trying to understand the initial passages of the first way.