Based on Sufficient Reason
P1) A contingent being exists.
- This contingent being is caused either (1) by itself, or (2) by another.
- If it were caused by itself, it would have to precede itself in existence, which is impossible.
P2) Therefore, this contingent being (2) is caused by another, i.e., depends on something else for its existence.
P3) That which causes (provides the sufficient reason for) the existence of any contingent being must be either (3) another contingent being, or (4) a non-contingent being (necessary) being.
- If 3, then this contingent cause must itself be caused by another, and so onto infinity.
P4) Therefore, that which causes (provides the sufficient reason for) the existence of any contingent being must be either (5) an infinite series of contingent beings, or (4) a necessary being.
P5) An infinite series of contingent beings (5) is incapable of yielding a sufficient reason for the existence of any being.
P6) Therefore, a necessary being (4) exists!
Based on the Principle of Existential Causality
1. Some limited, changing being[s] exist.
2. The present existence of every limited, changing being is caused by another.
3. There cannot be an infinite regress of causes of being.
4. Therefore, there is a first Cause of the present existence of these beings.
5. This first Cause must be infinite, necessary, eternal, simple, unchangeable and one.
6. This first uncaused Cause is identical with the God of the Judeo-Christian tradition
A mix of both
1. Something exists (e.g., I do);
2. I am a contingent being;
3. Nothing cannot cause something;
4. Only a Necessary Being can cause a contingent being;
5. Therefore, I am caused to exist by a Necessary Being;
6. But I am personal, rational, and moral kind of being (since I engage in these kinds of activities);
7. Therefore this Necessary Being must be a personal, rational, and moral kind of being, since I am similar to him by the Principle of Analogy;
8. But a Necessary Being cannot be contingent (i.e., not necessary) in its being which would be a contradiction;
9. Therefore, this Necessary Being is personal, rational, and moral in a necessary way, not in a contingent way;
10. This Necessary Being is also eternal, uncaused, unchanging, unlimited, and one, since a Necessary Being cannot come to be, be caused by another, undergo change, be limited by any possibility of what it could be (a Necessary Being has no possibility to be other than it is), or to be more than one Being (since there cannot be two infinite beings);
11. Therefore, one necessary, eternal, uncaused, unlimited (=infinite), rational, personal, and moral being exists;
12. Such a Being is appropriately called “God” in the theistic sense, because he possesses all the essential characteristics of a theistic God;
13. Therefore, the theistic God exists.