Argument by Proof

Not all beings are contingent

from Thomas Aquinas, Summa Theologica, paraphrased by Alvin Plantinga in "God, Freedom, and Evil" (p. 78)

by    @alexandershortt · 02/21/24


1
All beings are contingent

Contradiction of primary proposition

2
If all beings are contingent, then at one time nothing existed

Premise

3
Whatever begins to exist is caused to begin to exist by something else already existing

Premise

4
If at one time nothing existed, then nothing would have existed at a later time

According to 3

5
If at one time nothing existed, then nothing exists now

From 3 & 4

6
If all beings are contingent, nothing exists now

Follows from 1 and 5

7
Something exists now

Premise

8
Not all beings are contingent

6 & 7 contradict each other