I also gave (and will give) some notes on the cosmological arguments from Aquinas, Leibiz and Mackie.
Here are some additional notes:
Aquinas' Third Way
- There are at present contingent beings.
- Whatever can fail to exist, at some time does not exist.
- If all beings are contingent, then at one time nothing existed.(2)
- Whatever begins to exist is caused to begin to exist by something already existing.
- If at any time t nothing existed, then nothing would have existed at any later time. (4)
- If at one time nothing existed, nothing exists now. (5)
- If all beings are contingent nothing exists now. (3)(6)
- Not all beings are contingent; there is at least one necessary being. (1)(7)
- Every necessary being either has its necessity caused by another or has its necessity in itself.
- There cannot be an infinite series of necessary beings each having its necessity caused by another.
- There is a necessary being having of itself its own necessity, and this all men speak of as God. (8)(9)(10)
- x is a contingent being =df it is possible that x exists and it is possible that x does not exist
- x is a necessary being =df it is not possible that x does not exist
Criticisms:I. What is it to be a necessary being having of itself its own necessity, and why think that such a being is God?
II. Why think that (2) is true?
III. Does (3) follow from (2)?
(3') There is a time t such that for every contingent being B, B fails to exist at t.
(2*) For every person B there is a person A such that A is the mother of B.
(3*) There is a person A such that for every person B, A is the mother of B.