The first thought is to make sure which version of the cosmological argument you are talking about. There are at least three, so some people don’t like one but prefer another.
1). The Thomist cosmological argument seeks a first cause in terms of causal priority. It says that having a bunch of intermediate causes is like having a huge number of gears in a clock, no matter how many intermediate gears you have, unless you have a first cause, the clock won’t run.
2). The Leibniz Cosmological Argument (Also sometimes called the cosmological argument from contingency).
reasonablefaith.org/site/News2?page=NewsArticle&id=5847
It deals with necessity and contingency. It says that 1. everything that exists has an explanation of it’s existence (either in the necessity of its own existence or in an external cause), 2. If the universe has an explanation of its existence that explanation is God 3. The universe exists, has an explanation of it’s existence, and that explanation is God.
3). The Kalam Cosmological argument (my favorite, though I think Leibniz is good too). 1. Everything that begins to exist has a cause, 2. the universe began to exist 3. the universe has a cause.
reasonablefaith.org/site/News2?page=NewsArticle&id=5174
So the answer to your question is different depending on which version of the argument you use.
2). As applied to Leibniz’s argument, If every subsequent state is contingent (something else explains its existence), why should the first state be an exception? What magically makes that the case? Every apple tree is contingent on the previous, but the first is magically necessary?
- And at any rate, this form of the argument, takes the universe as a whole, and observes that everything in the universe is contingent, so why should the universe be an exception? To suggest that the universe is an exception is to commit the taxicab fallacy (the causal principle is not something you can dismiss like a cab when you have arrived at your destination).
3). As applied to the Kalam argument, “why can’t the first state just have existed.” If this is true, then the universe did not begin to exist because that first state would be part of the universe, and so the universe would always have existed for an infinite length of time. So what your question really does is to deny that the universe had a beginning. I find arguments that the universe had a beginning persuasive (impossibility of the formation of an actual infinite by successive addition, Big Bang cosmology and the expansion of the universe etc.). If the arguments that the universe began to exist are good, then the universe had a cause; this is God. The first state isn’t a cause of the universe because it is part of the universe. So what you are really saying is that the universe had no cause. But if the Kalam argument is good, this is untenable.
–another problem. This may also help. If the first state were the sole cause of the rest of the universe, then we should be observing the universe as infinitely old, not 13 billion years old. Why? Because if the first state always existed, it would always have been causing its effect, namely the subsequent state. So if the universe had no beginning and the first state of it was the cause of the rest, then we should be observing the universe as infinitely old. The only way to escape this seems to be to suppose a personal creator, since a man could be sitting down from all eternity and then choose to stand up. This would account for a 13 billion year old universe.
-finally, You ask if there is anything logically inconsistent in asserting that the first state “just was.” In the sense that there is no contradiction involved in making the statement, no. But that is not the question. The question is, is it “metaphysically” possible, or if you prefer, is it
really possible, I think the answer is no.