FIRST ARTICLE [I, Q. 46, Art. 1]

Whether the Universe of Creatures Always Existed?

Objection 1: It would seem that the universe of creatures, called the
world, had no beginning, but existed from eternity. For everything
which begins to exist, is a possible being before it exists: otherwise
it would be impossible for it to exist. If therefore the world began
to exist, it was a possible being before it began to exist. But
possible being is matter, which is in potentiality to existence,
which results from a form, and to non-existence, which results from
privation of form. If therefore the world began to exist, matter must
have existed before the world. But matter cannot exist without form:
while the matter of the world with its form is the world. Therefore
the world existed before it began to exist: which is impossible.

Obj. 2: Further, nothing which has power to be always, sometimes is
and sometimes is not; because so far as the power of a thing extends
so long it exists. But every incorruptible thing has power to be
always; for its power does not extend to any determinate time.
Therefore no incorruptible thing sometimes is, and sometimes is not:
but everything which has a beginning at some time is, and at some
time is not; therefore no incorruptible thing begins to exist. But
there are many incorruptible things in the world, as the celestial
bodies and all intellectual substances. Therefore the world did not
begin to exist.

Obj. 3: Further, what is unbegotten has no beginning. But the
Philosopher (Phys. i, text 82) proves that matter is unbegotten, and
also (De Coelo et Mundo i, text 20) that the heaven is unbegotten.
Therefore the universe did not begin to exist.

Obj. 4: Further, a vacuum is where there is not a body, but there
might be. But if the world began to exist, there was first no body
where the body of the world now is; and yet it could be there,
otherwise it would not be there now. Therefore before the world
there was a vacuum; which is impossible.

Obj. 5: Further, nothing begins anew to be moved except through
either the mover or the thing moved being otherwise than it was
before. But what is otherwise now than it was before, is moved.
Therefore before every new movement there was a previous movement.
Therefore movement always was; and therefore also the thing moved
always was, because movement is only in a movable thing.

Obj. 6: Further, every mover is either natural or voluntary. But
nei