I used to be an atheist. Then I have read a lot of Dolph's posts on the issue, I also read the God Delusion by Richard Dawkins and I have decided to convert *back* to being an agnostic.
There are a huge number of alternative theories when it comes to the exact origin and nature of the universe, and I find atheist a little too restricting. And here is my reasoning :
Whilst we could treat our entire universe scientifically, that depends on the ruleset defined within our universe, universal constants, rules, laws of mavity etc etc. Anything "within" this system that follows the rules of the system is defined as "natural", and by definition, anything that exists within the system but does no follow the rules is defined as "supernatural". I myself do not believe in the supernatural, but I half wish there was, it would make the universe much more interesting ^^ (though Dawkins himself calls "supernatural" in this case "perinatural", as in the natural that has not yet been discovered.
However, when it comes to a "god" or higher level entity, there are a few options that people don't really seem to explore. Here are some randoms examples from the top of my head :
1) A rational universe developed from the big bang, which is a random singularity (pure scientific atheist type universe)
2) A rational universe developed from the big bang, set in motion and configured by a higher level entity (a certain amount of theism required).
3) A rational universe developed from the big bang, set in motion and configured by a higher level entity (a certain amount of theism required), the creator himself within a universe (its own ruleset, big bang etc etc)
Now the "creator/meddler" model requires that the creator/meddler to be in a "higher level system" that is itself a type of system. Most religions simply define the higher level entity to be either *the system itself* or part of some system that is infinite and undefinable by man. But surely, it is possible that the system be similar to ours, possibly even started by its own "big bang"?
Then we could have universes inside of universes, where an entity from one level of universe "creates" the conditions for a lower level of universe, fulfilling the role of "god", without dismissing all the science which we have today. Incidently, the entity itself could be contained within its' own system or universe, which could also be defined as a set of rules, either by accident or by another entity. God having his own god, for example.
The problem with atheism is that it explicitly defines that this type of system, even if it eventually goes back up to a "self-developing" almost darwinian system, could not exist. That our universe is finite in its definition and cannot have higher levels of entities, systems outside of systems, parallel universes potentially *with* higher level entities whereas ours does not... etc etc. I find it a little restricting. Whilst I do not believe that an entity *does* interfere with the rules (supernatural abilities/miracles), it is just as possible as if we could look into a lower "dimension" of life and effecting it somehow.
I just don't think science/philosophy can handle all the options coming from a purely atheist background, especially concerning the constants, laws and boundaries of our universe are concerned.