Do atheists have a standard definition of "God"? If not, what is it that they disbelieve?

As I understand it, one way of defining an atheist is as someone who thinks the statement, "There does not exist an x such that x is a deity" is true. But religions have different ideas about what constitutes a (or "the") deity, leaving atheists in the position, "For any reasonable definition of 'deity', there does not exist x such that x is a deity". How do atheists manage this universal quantifier, without allowing "deity" to become weak enough that "nature" or "the universe" provides an example?

God is a personification of the universal superrational strategy for asymmetric games. This is "ethical God", and it is what religions are pushing predominantly. In addition to this notion, which is interesting, important, and true, there are other notions which are ridiculous:

  1. Creator God: created the universe, set it in motion.

  2. Snoopy God: snoops on you while you have sex, and waggles his finger.

  3. Supernatural God: looks at the list of daily prayers, and comes down and rearranges atoms to make things better for religious folks.

These things are ridiculous to anyone who has any sort of scientific sense. The creation of the universe from outside (as opposed to its evolution from inside) is not something which can be probed by instruments of tests, and you can believe whatever you want about it, including that the universe was created 3 minutes ago, or it hasn't been created yet, we are just in the "false memory" stage right now. These questions are meaningless in the sense of Carnap, and this debate is just ridiculous, nobody needs to worry about it, because there is no sense in it.

Snoopy God is sort of like saying that when you hand-calculate pi to 20 digits, and you get the last 6 digits wrong (this happened to me), you have somehow tried to change the value of pi, and pi gets angry and comes to haunt you in your dreams, then banishes you to mathematician's hell. It doesn't. But you still made a mistake.

The problem is that the ethical God baby, the self-consistent entity whose desire is absolute good, is thrown out with the superstitious bath. If these concepts are separated clearly, I think there will be no more debate, or rather, the debate will be about the best course of human action in various circumstances, given circumstances of tradition and history, rather than about superstitious or positivistically meaningless nonsense. The debate on ethical behavior is informed by the knowledge that there is a self-consistent notion of superrational ethics extending to all games, and that some 3rd century saints and martyrs had an inkling of this, and made all sorts of arguments about how to determine the universal ethical good which one should not ignore.

A related concept is the concept of eventual determination of the truth or falsity of every arithmetic statement from a strong enough axiom of higher infinity. This is tantamount to the idea that by approximating ordinals closer and closer to the Church-Kleene ordinal, one creates mathematical systems which are ever closer to the otherwise hard-to-define concept of arithmetical truth. The concept of Arithmetical truth is generally an article of faith of mathematicians, and the idea that one can approach it by evolutionarily producing bigger ordinal names is parallel to the idea that one can approach an understanding of God by debating ethics within historical time, while reading and accepting/rejecting the opinions in religious texts. Evolution is required, because no fixed system is going to produce all arithmetic truths.

Abrahamic religions tend to define God as an all-powerful, all-knowing, sentient being. I don't believe such a being exists.

Some religions claim there was a sentience behind human life. I don't believe that.

Some religions define gods as super-powerful beings that take an interest in humans. I believe we have no evidence such beings exist, though I suppose there might be powerful space aliens out there somewhere.

Some religions posit a supernatural realm exists -- a realm that's not material but that can interact with matter. I don't believe in that.

Some religions define gods in a vague way. I can't say much about that, because it's vague.

Some religions use the word "god" as a synonym for natural forces, e.g. "God is the Universe." I believe that the Universe exists. I'm not sure what the point is of calling it "god," unless you're claiming it's sentient. I don't believe it's sentient.

As an atheist, I am an equal opportunity unbeliever. I have no belief in any god or gods. That's it. For me, a god must have some element of the supernatural, and it's that supernatural part in which I have no belief. If someone wants to use the word god as a metaphor for something else -- as Einstein often did, to the confusion of many believers -- then, as far as I'm concerned, that's a metaphor, not a god, and I'm not interested.