CFS-WB-CH04

First Mover: The necessary,
uncaused being, or God, who
first set everything in motion.
If there were
no first cause
that put
everything in
motion, nothing
whatsoever
would move.
infinite number of steps is not completable. So, what does this mean?
There must be a First Mover.
What, then, must a first mover be like? It cannot be something that
needs to be moved from potency to act, otherwise it would itself require
a mover. Additionally, the first mover must have the capacity to
move all other objects to act, because it is the source (first) to move all
subsequent changes from potency to act.
The key principle of Aquinas’s argument is underlined and is necessarily
true: “But this cannot go on to infinity, because then there would
be no first mover, and, consequently, no other mover.” What is true of
one thing in motion (change) is true of the collective motion (change)
of the entire universe. If there were no first cause that put everything
in motion, nothing whatsoever would move. There would be no motion
(change) in anything, so there must be an unmoved mover that set everything
else into motion. This First Mover is God. Let us look at the
second proof, which builds upon the first and strengthens it.
The Second Way
The second way is from the nature of the efficient cause.
■ Simple Observation: In the world of sense [like sight], we find there
is an order of efficient causes.
■ Major premise: There is no case known (neither is it, indeed,
possible) in which a thing is found to be the efficient cause of itself;
for so it would be prior to itself, which is impossible.
■ Minor premise A: Now in efficient causes it is not possible to go
on to infinity, because in all efficient causes following in order, the
first is the cause of the intermediate cause, and the intermediate is
the cause of the ultimate cause, whether the intermediate cause be
several, or only one. Now to take away the cause is to take away the
effect.
■ Minor premise B: Therefore, if there be no first cause among
efficient causes, there will be no ultimate, nor any intermediate
cause. But if in efficient causes it is possible to go on to infinity,
there will be no first efficient cause, neither will there be an ultimate
effect, nor any intermediate efficient causes; all of which is plainly
false.
■ Conclusion: Therefore, it is necessary to admit a first efficient
cause, to which everyone gives the name of God.
This argument is similar to the first but arrives at its conclusion by a
different route. Whereas the first way is rooted in the observation that
74 Apologetics I: The Catholic Faith and Science
© Magis Center