The Complete Aristotle (eng.)

are to explain
the observed facts, that for each of the planets there should be
other spheres (one fewer than those hitherto assigned) which
counteract those already mentioned and bring back to the same
position the outermost sphere of the star which in each case is
situated below the star in question; for only thus can all the
forces at work produce the observed motion of the planets. Since,
then, the spheres involved in the movement of the planets
themselves are—eight for Saturn and Jupiter and twenty-five for the
others, and of these only those involved in the movement of the
lowest-situated planet need not be counteracted the spheres which
counteract those of the outermost two planets will be six in
number, and the spheres which counteract those of the next four
planets will be sixteen; therefore the number of all the
spheres—both those which move the planets and those which
counteract these—will be fifty-five. And if one were not to add to
the moon and to the sun the movements we mentioned, the whole set
of spheres will be forty-seven in number.
    Let this, then, be taken as the number of the spheres, so that
the unmovable substances and principles also may probably be taken
as just so many; the assertion of necessity must be left to more
powerful thinkers. But if there can be no spatial movement which
does not conduce to the moving of a star, and if further every
being and every substance which is immune from change and in virtue
of itself has attained to the best must be considered an end, there
can be no other being apart from these we have named, but this must
be the number of the substances. For if there are others, they will
cause change as being a final cause of movement; but there cannot
he other movements besides those mentioned. And it is reasonable to
infer this from a consideration of the bodies that are moved; for
if everything that moves is for the sake of that which is moved,
and every movement belongs to something that is moved, no movement
can be for the sake of itself or of another movement, but all the
movements must be for the sake of the stars. For if there is to be
a movement for the sake of a movement, this latter also will have
to be for the sake of something else; so that since there cannot be
an infinite regress, the end of every movement will be one of the
divine bodies which move through the heaven.
    (Evidently there is but one heaven. For if there are many
heavens as there are many men, the moving principles, of which each
heaven will have one, will be one in form but in number many. But
all things that are many in number have matter; for one and the
same definition, e.g. that of man, applies to many things, while
Socrates is one. But the primary essence has not matter; for it is
complete reality. So the unmovable first mover is one both in
definition and in number; so too, therefore, is that which is moved
always and continuously; therefore there is one heaven alone.) Our
forefathers in the most remote ages have handed down to their
posterity a tradition, in the form of a myth, that these bodies are
gods, and that the divine encloses the whole of nature. The rest of
the tradition has been added later in mythical form with a view to
the persuasion of the multitude and to its legal and utilitarian
expediency; they say these gods are in the form of men or like some
of the other animals, and they say other things consequent on and
similar to these which we have mentioned. But if one were to
separate the first point from these additions and take it
alone-that they thought the first substances to be gods, one must
regard this as an inspired utterance, and reflect that, while
probably each art and each science has often been developed as far
as possible and has again perished, these opinions, with others,
have been preserved until the present like relics of the ancient
treasure. Only thus far, then, is the opinion of our ancestors and
of our earliest predecessors clear to us.
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9
    The nature of the divine thought involves certain problems; for
while thought is held to be the most divine of things observed by
us, the question how it must be situated in order to have that
character involves difficulties. For if it thinks of nothing, what
is there here of dignity? It is just like one who sleeps. And if it
thinks, but this depends on something else, then (since that which
is its substance is not the act of thinking, but a potency) it
cannot