A: I’m open to cosmological arguments, but not to ones that argue to a necessary being.
B: What’s wrong with those?
A: The universe is as necessary as any being can get, as far as I can tell.
B: Why so?
A: Because if something is not necessary, it can be otherwise.
B: Yes. So?
A: But then it can only be otherwise at some time?
A: But there’s no time at which the universe cannot exist. Even Augustine figured this out. No universe, no time. Augustine even thought this included angels.
B: You are missing what possibility means. When I say “it can be otherwise at some time” I mean it can be otherwise than it is at the same time when it is. You don’t need some other, later time for it to be otherwise.
A: That’s just not true. A thing can’t be other than it is when it is. That would it require that it could be simultaneously what it is and something else.
B: Oh. I get it. So it needs some other time.
A: But there’s no other time for the universe. So it can’t be otherwise. So it’s a necessary being. Q.E.D.
A: Let me regroup. Do you agree with this? If the universe stopped existing, it would not be necessary?
B: That seems hard to argue with. Even if it took all time with it, I’d still call the whole thing contingent.
A: But then a thing can contingently exist, even if there is no other time for its non-existence.
B: So I have to choose which I premise I want to keep: (a) a real possibility needs some other time and (b) if the universe stopped existing, it would be contingent. I guess I choose (b).
A: So then your argument won’t work to show the universe is necessary. I want to say more though. Let’s start with Aristotle’s claim that if the universe existed for an infinite time from now, then it must be necessary.
B: Why did he say that?
A: Because if it existed to the end of the infinite time, there would be no other time for it to collapse into non-existence.
B: But he seemed to make the mistake that the universe needs another time in order to be contingent.
A: I want to suggest that that it’s just this “going to the infinite” that a necessary universe would have to accomplish. But how could it get to some point infinitely far off? Any point it got to would be one that was a finite distance from now.
B: So you want to claim the universe can’t be necessary. It either (a) exists to some infinite time or (b) not. If (b) is true, it’s clearly contingent, but (a) is impossible, since all “infinite” means is that there will always be some next moment. In neither case is the universe necessary. What will not exist for an infinite time from now is not necessary, but it is impossible to exist for an infinite time from now.
A: Right. It’s contingent whether it gets to some last time or not.
B: But then we get a cosmological argument from the experience of things in time.