Tahafut_al-Tahafut-transl-Engl-van-den-Bergh

defined acts can only arise from beings perceptive, living, capable of
choice and of willing.
And he becomes still more convinced of this when he sees that many
beings in this world which have small, despicable, miserable, and
insignificant bodies are not wholly devoid of life, notwithstanding the
smallness of’ their size, the feebleness of their powers, the shortness of
their lives, the insignificance of their bodies; and that divine munificence
has bestowed on them life and perception, through which they direct
themselves and conserve their existence. And he knows with absolute
certainty that the heavenly bodies are better fitted to possess life and
perception than the bodies of this sublunary world, because of the size of
their bodies, the magnificence of their existence, and the multitude of their
lights,’ as it says in the Divine Words: ‘Surely the creation of the heavens
and the earth is greater than the creation of man, but most men know it
not. But especially when he notices how they direct the living beings of
this sublunary world, does he understand with absolute certainty that they
are alive, for the living can only be guided by a being leading a more
perfect life. And when man observes these noble, living, rational bodies,
capable of choice, which surround us, and recognizes a third principle,
namely, that they do not need for their own existence the providence with
which they guide the sublunary world, he becomes aware that they are
commanded to perform these movements and to control the animals,
vegetables, and minerals of this sublunary world, and that He who
commands them is not one of them and that He is necessarily incorporeal
(for, if not, He would be one of them) and that all these heavenly bodies
control the existents which are under them, but serve Him, who for His
existence is in no need of them. And were it not for this Commander, they
would not give their care everlastingly and continuously to this sublunary
world which they guide willingly, without any advantage to themselves,
especially in this act. They move thus by way of command and obligation
the heavens which repair to them, only in order to conserve this sublunary
world and to uphold its existence. And the Commander is God (glory be to
Him), and all this is the meaning of the Divine Words ‘We come willingly’.
And another proof of all this is that, if a man sees a great many people,
distinguished and meritorious, applying themselves to definite acts without
a moment’s interruption, although these acts are not necessary for their
169