Anyway, the vast majority of these "proofs" have one of these two basic forms:
- Something unknown caused X. That something was God.
- X is immaterial/transcendental/supernatural. God is immaterial/transcendental/supernatural. Therefore God exists.
The first is, of course, an argument from ignorance. Since something has no (apparent) explanation, that something is then attributed to "God." No further justification needed. Furthermore, in many cases even the premise (ie. "something caused X") is an unjustified assumption. However, even if it were true, the jump in logic is still astounding.
The second form has a multitude of fallacies packed into one. So many, in fact, that listing them all is quite lengthy.
Its basic form is, of course, the so-called fallacy of the undistributed middle ("X has some property, Y has the same property, therefore X is Y; or they share other properties beside that one.") In some cases it could also be considered a post hoc fallacy ("X and Y share some property, therefore X caused Y.")
Moreover, it usually outright starts with a blatant, unjustified assumption, which makes a claim about something without even considering the alternatives. This is often a so-called category error, in other words, categorizing something as something else (one example being, categorizing "sentience" as an entity that exists all by itself independent of a brain, rather than it being a function, something that describes the physical properties and external behavior of a brain.)
The second premise (ie. "God has property X") is, of course, completely fallacious. It's a begging the question fallacy: It already assumes what the whole argument is trying to prove (ie. that God exists and has certain properties.) This also makes it circular logic.
This last thing is, in fact, what makes this type of logic so amusing. It kind of tries to "sneak in" the whole existence of a god without having to justify it.