Chapter 070 - The Work of the Fourth Day

On the Fourth Day luminaries were added by way of ornament. For first are placed those works of creation and variety which are intrinsic as parts of a whole; while on this Day the heavens were adorned with luminaries which move in them. On the Fifth Day the elements were adorned with fishes and birds; and on the Sixth Day the earth, with animals. And since creatures were made, either for themselves, or for other creatures, or for the universe, or for the glory of God, it was fitting with regard to the luminaries that a cause for their production should be mentioned, namely, that they were placed as signs; lest, perhaps, man should be deceived into adoring them as gods, whereas they are only intended to give light, and to direct his actions by serving for the measurement of time, to take away weariness, to assist in the production of food, and by foretelling rains and fair weather, to aid the different occupations of life.

Although there seem to be differences of opinion among philosophers and theologians as to whether or not the heavenly luminaries are animated, in reality there is little difference; for the heavenly bodies have no sort of soul united to them as form, but only as motor. And since the operations of vegetable and animal life are not suitable to bodies which are incorruptible by nature, those of motion and understanding only can belong to the celestial motors. For desire follows sense, while intellect bears relation to both; and since the operation of the intellect is not exercised by the body, it does not require the body, unless it be to receive phantasms by the senses. But as the operations of the sensitive soul do not become celestial bodies, they are not united to souls for the sake of intellectual operation, but for the sake of motion only. For this purpose it is not necessary that they be united as form; it suffices for virtual contact that they be united as the motor to the thing moved. Thus Plato held that spiritual substances were united to the celestial bodies as motors to moveable.