In an effort to rescue the thread from WW's rude distraction, here's an essay I typed out quickly about 5 years ago when asked why I don't believe in God. It's a bit rambly, but it will do in a pinch:
First, you have to define the term "God." The problem with most theists is that this term is a moving target.
In addition, because there is no direct evidence either for or against the existence of any God, you cannot use deductive logic (a+b=c; therefore c-b=a). You can only reach a conclusion by inductive reasoning using the balance of evidence (90% of A is also B; C is B, so the chances are 90% that C is also A).
I will assert that the only RELEVANT definition of God states that GOD INTERVENES TO CIRCUMVENT NATURAL LAWS.
But if God circumvents natural laws, then it becomes impossible to understand natural laws. All scientific findings would necessarily include the stipulation, "It is also possible that these results are an act of God, a miracle, thereby making our research meaningless."
However, we have been able to expand our knowledge of natural laws (evidenced by every appliance in your kitchen). Therefore, because the scientific method leads to applicable discoveries, and the likely conclusion is that God, at least the intervening kind, does not exist.
Additionally, if God is defined as all loving, all powerful, and all knowing, then it is impossible to explain suffering. Either God is not all loving (he acts sadistically), not all powerful (he cannot prevent suffering), or not all knowing (he created suffering by mistake because he didn't know the consequences of his actions). A God who is not all-loving, all-powerful or all-knowing is also not sufficient for the definition of God, because any God that fails to meet these criteria becomes bound by rules that are greater than God.
If God is bound by external rules and/or does not intervene in our existence, then God is either non-existent or irrelevant. The classic Bertrand Russell argument is that I cannot prove that a china teapot is orbiting the sun between the earth's orbit and Mars. But while I cannot prove this is not true, the evidence against it is compelling.
And while it is not possible to prove beyond any doubt that some god exists, it makes enormously more sense to live your life as if there were no God.
It is more compelling to me that humans have invented all the gods ever described (a) to help people deal with the pain and fear associated with confusion, death, and loss, and (b) to reflect the thoughts of the ruling powers in a particular time. (In Roman times, they elevated the emperors to god-status. In the US, Christians have bought into such beliefs as "manifest destiny" and "American exceptionalism.")
Humans have always searched for explanations. When none were easily found, it has been the natural inclination to declare that the cause of the unexplained was "God" (or gods). (It's reassuring to think you know things, even when you don't.) Confirmation bias led believers to attribute "miracles" (coincidences) and laws to this Divinity, and over time a series of orthodoxies emerged.
Now it seems unhelpful and in many ways maladaptive to believe in such superstition. The only matters that aid in our ongoing well-being are genetics, work, location, health, culture, sustenance, and pure, blind luck.





