- Everything has a cause
- Nothing is its own cause
- A causal loop cannot be infinte
- Therefore, there must have been a first cause
- The first cause is God
To explain why this does not prove the existence of God, I need to explain a few things about a philosophical concept called Occam's Razor. This principle tells us that if we have multiple explanations for a phenomenon that all explain the phenomenon, then the simplest argument is the one that is most likely correct. For an argument to be simple, it needs to not rely on unnecessary assumptions about the phenomenon at hand. For example, I could say that either a giant dolphin guides the Earth around the Sun or the Earth simply rotates around it. Both adequately explain the fact that the Earth moves around the sun, but the dolphin guiding the Earth is an unnecessary assumption.
So, why doesn't the first cause argument prove God's existence? If we examine the argument, the biggest thing that comes to mind is an infinite regression.
If everything has a cause, then so does God. If God has a cause, then that cause would have to have a cause, and so on and so forth. What you would end up with is an infinite regress that does not mean anything.
What if God was the uncaused first cause? If we make that leap, then the principle of Occam's Razor comes into play. Why can't nature be the uncaused first cause? Why make that leap to God when a much simpler explanation exists, one that doesn't rely on unnecessary assumptions about the universe. Ultimately, if you want to claim God as the first cause you will eventually have to introduce an uncaused first cause, and to claim God as the uncaused first cause is an unnecessary assumption.
So, now I'll ask the question. Why does the first cause have to be a who? And more importantly, why does it have to be a God, or some god-like being. Why couldn't the first cause be a what, an event, or a happening. We have a good explanation for the beginning of the universe called the Big Bang theory (which, by the way, is not the greatest name for the theory).
I'll go ahead and take another step ahead. The uncaused first cause CANNOT be a being. For a being to be the uncaused first cause it would have to exist outside of space and time (many people claim god does). The problem is, as soon as you remove time, you get rid of the concept of causality. A comes before B, therefore A causes B (note, it's a logical fallacy, but it's just an example). Cause must come before effect, and if a being has to cognitively make the decision to create the universe that would require that being to have some concept of time, which creates a paradox (because earlier it was claimed that this being exists outside of space and time). However, if this event was random, then it wouldn't depend on time, and therefore could be possible. While we don't know perfectly where the universe came from, the Big Bang theory is a good answer that doesn't create a paradox.