A Prime Mover argument is simply one that states that, since every event needs a cause, there must be some first cause that started the universe moving, an “uncaused cause”, and that this must be God.
This argument is subject to numerous serious faults.
Secondly, this is a deistic substitution argument, which is to say that it is often used as a theistic proof (i.e. Proof for a particular god, such as the god of Abraham), when in fact it is only a deistic argument (i.e. an argument for a higher power). Every clement of a prime mover argument can be granted, and it still wouldn’t prove, or even suggest, the existence of any particular god (Zeus, Poseidon, Shiva, God) over any other one, nor would it mean that a word in any creation text, like the bible, is true.
Now the most famous prime mover arguments are from St. Thomas Aquinas’ Quinque Viae, or his “Five Proofs” for god. The first three “proofs” are essentially the same principal, arguing from causality–something must be the first “event” (and his fifth argument, while slightly different, rests on the notion of causality as well, so it’s susceptible to some of the same faults). But all of his five proofs, and indeed all prime mover arguments, have a rather serious second fault (also common to God of the Gaps arguments) which is that they don’t argue for God. They are Deistic arguments for a higher power, that’s all. Prime mover arguments are one of the first lines of defense for theologians–you see it in nearly every formal debate and argument–and it’s nothing more than an argument for a higher power. Not even St. Thomas Aquinas could coax any of them into an argument specifically for his Abrahamic God. Grant every prime mover argument ever made, and it’s not a shred more proof for Yahweh over, say, Poseidon.
The final problem with these arguments is that the given answer “it must be god” is an a priori answer, not a logical one. This entire argument rests on a paradox, that the nature of the universe, as our finite brains understand it, is that everything has a cause. But our brains also have a need for a first cause. We understand time chronologically and insist that something must come first. But if something comes first, then it didn’t have a cause, and violates the first rule. So we define god so as to end all debate on the subject. We say that the definition of god (obviously) includes within it that he doesn’t need a first cause. It’s a priori. Well why doesn’t he need a first cause? Well, nothing, that’s what makes him the prime mover. Well, wait a minute, if God doesn’t need a prime mover, why does the universe need one? Well how else would it start? Note the circular reasoning, and the introduction of this artificial entity, god, whose sole purpose is (as in any gaps argument) to end the discussion. But why is it that God can get away with it and the cosmos can’t? Indeed, all you’ve done is add a layer of complexity, which Occam’s razor suggests is the wrong way to go. Indeed nobody ever got the right solution by finding a good solution, then arbitrarily adding a layer of complexity. It’s consciousness bias, this suggestion that a “consciousness” can somehow violate the laws of cause and effect where an inanimate object cant, and is filled with bad assumptions (not the least of which is free will: what makes you think you have that? A human being may make poor decisions, and decisions may be so complex so as to be unable to trace the decision making process, but there always is one. Does anyone ever do anything ‘for no reason’? Is any human action truly random? No, our minds, as error prone as they are, are still bound by the laws of cause and effect).
Notice the circular, a priori argument. We’ve defined the prime mover to be the first thing, defined it not to have a cause, and deafened against assaults on the logic of prime mover by saying “no, we’ve declared that nothing caused him, so nothing did”—but this puts us back in the same position as we started with before the argument was posited—we don’t know how it all started–to question how did god come about is to violate a premise of the argument.
That’s a seriously important question… If god can exist without a cause, why can’t the cosmos? Why do we have a “consciousness bias” which states that something must have made a choice to create the universe, and why do we not have the same bias about that consciousness…. Why did nothing need to create that consciousness? Why the double standard?
Prime mover is an argument to explain how the universe started without a cause. It fails to do that, since God still needs a cause (ontological arguments notwithstanding)—we just say he doesn’t to simplify the matter on the grounds that we don’t understand god (but then why do we need him? Why not say we don’t understand the universe. Why add this god, which we don’t understand, to explain a universe we don’t understand).
And even ignoring all of these failings, the prime mover argument only would account for a deistic god, not a theistic one. Prime mover, nearly universally used by those defending Christianity, is no more a deference of God than of Zeus, Odin, Vishnu, Osiris, or some other nonsensical thing, and gives absolutely no credence towards the notion of any theistic god anywhere.