Philosophy

AQUINAS’S FIRST WAY

1. It is obvious from observation that some things in the world are in a process of change or motion.

2. To change is just to go from being potentially a certain way to being actually that way.

3. To make itself actual, a potential would have to be actual already.

4. But nothing can be both potential and actual in the same respect and at the same time.

5. So no potential can make itself actual.

6. So nothing can change itself; whatever is changed must be changed by something else.

7. Anything that changes another thing, if it is itself changed, must be changed by yet another thing.

8. If this series of changers were infinite, then there would be no first changer; and in that case, there would be no subsequent changers nor any change at all, for there would be nothing to initiate change.

9. So there must be a first unchanging changer or unmoved mover; and this is just what we call God.

TWO KINDS OF CAUSAL SERIES

Accidentally ordered (per accidens, linear) Essentially ordered (per se, hierarchical)

… A → B → C → D → E → F … A

B C D

E F G H I

Extends over a span of time, with members Exists at a moment of time, with members operating

operating non-simultaneously simultaneously here and now

E.g. a father who begets a son, who in turn begets E.g. a stone which is moved by a stick which is in turn another, who in turn begets yet another moved by a hand

If any earlier member goes out of existence, the If the first member goes out of existence, the whole series can still continue series collapses

Members have independent causal power Lower members are dependent on and instruments of the first cause, which is the only member with “built in” or underived causal power

Can in theory be infinite Cannot possibly be infinite: if there were no first cause imparting causal power to the others, there

would be no series at all

Is NOT the kind of series Aquinas is talking about IS the kind of series Aquinas is talking about