To respond to the OP:
The atheist believes that there is no higher power.
The agnostic does not make a solid claim on the existence of a higher power.
The deist believes that a higher power exists, but that it does not influence our world beyond setting it in motion.
The theist believes that there is a higher power that is personally and morally vested in everything that happens in the universe, including (perhaps especially) intimate human matters.
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Creationist arguments I hear all the time:
1. If the universe was created out of nothing, then God must have created it, since you can't get something out of nothing.
We don't know if there was ever "nothing." Furthermore, we know very little about how "nothing" actually is. What is no matter, no space, no time, no probability? We simply _don't_ know that "nothing" can't actually beget something, destroying itself.
Given that God did create the universe out of nothing, then we are producing a contradiction- there wasn't nothing before God created the universe, because God was there. God isn't nothing, then there was never nothing. The argument collapses. You could just say that the universe was always there, and is always going to be there (everything is here now and was always here), which would make much more sense given the definition that God is omnipotent, omnipresent and eternal (to me, this means God literally is all matter and energy in the universe; proving this being has a will is still a long ways ahead).
2. God set the universe in motion, though it was always there. The conditions for our existence are on an exact knife-edge.
If we are to abandon a bit of egocentrism, we could simply say that we evolved because the necessary conditions happened to exist for us. There is an infinity of alien species that did not evolve because the conditions were not right for them, and what should we call that? Divine destruction? I will simply point out the incredible arrogance that goes with the assumption that the universe was created with our existence as a goal- for only with this supposition does it follow to think of the universe as an accurate shot, immaculately created to house us.
Our conditions, being thinly balanced and accomodated for by this vast universe, do not require a designer. I don't know if we should hold it to the credit of God for creating us on such an unstable balance. Why is it a testimony of design for us to be a fragile life form on a temporary planet? How is that an indicator of design rather than coincidence? Our planet, and our solar system, by the way, are going to be inhospitable to human life, with time. What are we flattering God for?