Are there any logical reasons to believe in God? Countless people over the ages have at least briefly considered this question, and the issue is not without relevance today. Certainly the chasms separating literal believers, moderate believers and nonbelievers are deep. There are many who seem content to believe God exists simply because he says he does in a much extolled tome that he allegedly inspired. Many others subscribe with varying degrees of fervor to more sophisticated arguments for God, while atheists and agnostics find none of the arguments persuasive.

Such questions of existence and belief intrigued me early on. As a child, I humored my parents when they talked to me about Santa Claus, a decidedly nonreligious figure. Wanting to protect them from my knowledge of his nonexistence, I feigned belief. My qualitative "order of magnitude" calculations had convinced me there were too many expectant kids around the world for this Mr. Claus to come close to making his Christmas Eve rounds in time, even if he didn't stop for the occasional hot chocolate.

My youthful number sense evolved into an adolescent skepticism, dismissive of just-so tales devoid of evidence. The absence of an answer to the question "What caused, preceded or created God?" made, in my eyes, the existence of the latter an unnecessary, antecedent mystery. Why introduce him? Why postulate a completely non-explanatory, extra perplexity to help explain the already sufficiently perplexing and beautiful world? Or, if one were committed to such an unnecessary mystery, why not introduce even more antecedent ones such as the Creator's Creator or even his Great Uncle?

As the above no doubt suggests, I've always found discussions of the existence of God more holey than holy, and so I've tried in my recent book Irreligion to examine, briskly and formally, their inherent illogic. The arguments considered range from what might be called the golden oldies of religious thought to those with a more contemporary beat, the playlist including the first-cause argument, the argument from design, the ontological argument, arguments from faith and biblical codes, creationist probability arguments, the argument from the anthropic principle, and others. I sketch with a lightly heretical touch only the most trenchant refutations of the arguments for God, just the gist with an occasional jest.

The book notwithstanding, I don't consider myself an "angry atheist." I don't agree with, but have little problem with those who simply maintain a nebulous but steadfast belief in "something more" (a large percentage of Americans, according to the just-released report of the Pew Forum). And I don't contest those who note that religion has been and can be a source of enlightening stories and metaphors, of inspiring ideals and values, of satisfying rituals and traditions. It is also undeniable that religion has led and can still lead to hatred, cruelty, superstition and fanaticism.

In this last regard, the vituperative e-mail I've received from religious literalists in response to Irreligion has led me to conclude that there is a much more fruitful distinction than the common one between atheists and theists. The real fissure is that between those who acknowledge that there are no compelling logical arguments for God's existence (even if they choose to believe and practice their religion anyway) and those who are certain not only of God's existence but also of the verbatim truth of their particular holy book with all its idiosyncratic inconsistencies and egregiously false pronouncements.

Yet time and again we indulge fundamentalists from every religion much more than H.L. Mencken suggested is necessary when he wrote, "We must respect the other fellow's religion, but only in the sense and to the extent that we respect his theory that his wife is beautiful and his children smart."

We aren't so forgiving in other domains. Almost everyone would concede, for example, that a presidential candidate who wanted to outlaw interest on loans and revert to a barter system would be an absurd steward for our troubled economy. So why isn't there a similar consensus that someone who believes the Earth is 6,000 years old and that Noah's Ark is an event in zoological history would be an absurd leader on issues such as stem-cell research, climate change and renewable resources?

While not a panacea for our ills, candidly recognizing the absence of any good logical arguments for God's existence, giving up on divine allies and advocates as well as taskmasters and tormentors, and prizing a humane, reasonable and brave outlook, just might help move this world a bit closer to a heaven on Earth.