This argument has been put forth by Norman L. Geisler, a classical apologist and one of the few Protestant scholars who specializes in Thomistic thought. By the way, I don’t think God expects people to master this argument in order to find Him. I know the average person does not have the time to think through such a sophisticated apologetic.
Anyway, let’s move forward. First principles are the foundation of knowledge. Without them nothing could be known. Even coherentism uses the first principle of noncontradiction to test the coherence of its system. Realism affirms that first principles apply to the real world. First principles undeniably apply to reality. The very denial that first principles apply to reality uses first principles in the denial. Without basic first principles of reality, nothing can be known. Everything we know about reality is known by them. Twelve basic first principles can be set forth. 1. Being Is (B is) = The Principle of Existence. 2. Being Is Being (B is B) = The Principle of Identity. 3. Being Is Not Nonbeing (B is Not Non-B) = The Principle of Noncontradiction. 4. Either Being or Nonbeing (Either B or Non-B) = The Principle of the Excluded Middle. 5. Nonbeing Cannot Cause Being (Non-B > B) = The Principle of Causality. 6. Contingent Being Cannot Cause Contingent Being (Bc > Bc) = The Principle of Contingency (or Dependency). 7. Only Necessary Being Can Cause a Contingent Being (Bn → Bc) = The Positive Principle of Modality. 8. Necessary Being Cannot Cause a Necessary Being (Bn > Bn) = The Negative Principle of Modality. 9. Every Contingent Being Is Caused by a Necessary Being (Bn → Bc) = The Principle of Existential Causality. 10. Necessary Being exists = Principle of Existential Necessity (Bn exists). 11. Contingent being exists = Principle of Existential Contingency (Bc exists). 12. Necessary Being is similar to similar contingent being(s) it causes = Principle of Analogy (Bn — similar → Bc)
Given these principles of being, one can know many things about reality; they relate thought and thing. Knowing is based in being. By these principles, one can even prove the existence of God as follows:
1. Something exists (e.g., I do) (no. 1). 2. I am a contingent being (no. 11). 3. Nothing cannot cause something (no. 5). 4. Only a Necessary Being can cause a contingent being (no. 7). 5. Therefore, I am caused to exist by a Necessary Being (follows from nos. 1–4). 6. But I am a 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 (no. 12). 8. But a Necessary Being cannot be contingent (i.e., not-necessary) in its being which would be a contradiction (no. 3). 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.
Sources: Geisler, N. L. (1999). BECA: Grand Rapids, Mich.: Baker Books.