This is what Robert G. Ingersoll experienced when he became convinced that the universe was natural, that there were no gods and "no prohibited places in all the realms of thought". It is a wonderful way for Victor Stenger to open his latest book, because it captures what many of us feel having made the positive step from either belief or vague agnosticism into the clear air of atheism. It is also extremely vexing to believers. The "old-school atheists" like Nietzsche, Camus and Sartre at least had the decency to wander in the "disorienting wilderness of nihilism" and to indulge in "angst-ridden anxiety and serious soul-searching". Miserable atheists, like the poor, are there to be pitied and then forgotten. The smiling confidence - sorry, "arrogance" - of atheists like Richard Dawkins and Ariane Sherine seems to threaten those who mistake the quicksand of faith for solid ground.

In a world in which we already have denominational overload, where you can be a theist, deist, Buddhist, spiritualist, agnostic, and (so long as you're not running for public office in America) atheist, why on earth introduce another category of "new atheist" to confuse the punter? "Perhaps the most unique position of New Atheism is that faith, which is belief without supportive evidence, should not be given the respect, even deference, it obtains in modern society. Faith is always foolish and leads to many of the evils of society." Stenger identifies an important principle - don't respect the unjustified beliefs of others - that is unproblematic in most areas of life, except where religion is concerned. While religious folk fondly imagine they're dealing with the "big questions", they can't even handle the smaller ones to do with, for example, the historicity of Jesus. (See how they respond to Bill Maher in the excellent Religulous [DVD] [2008].)

In one sense, I like the term New Atheist, even the Victorian indulgence in capitals. Stenger is clear as to what the real differences between nonbelievers and believers are. Is nature all there is or is there a supernatural dimension? Do theists have a "superior channel to reality, provided by God's revelations"? One man who "claimed the authority of divine revelation" was Joseph Smith, founder of the Mormon Church. He "had a taste for women, and one of his most important revelations was that God wanted men to have multiple wives." How convenient. But is it any less strange to believe in a walking corpse? At least we know Smith existed.

In another more important sense, however, the term "new atheism" is inaccurate because it occludes historical figures, such as that great champion of free thought W. K. Clifford, who declared over a hundred years ago that "it is wrong always, everywhere, and for anyone, to believe anything upon insufficient evidence". This is, if anything, even stronger than Stenger's denunciation of faith as "belief in the absence of supportive evidence and even in light of contrary evidence". Faith communities often bang on about their traditions, even if they've involved "slavery, the oppression of women, ethnic cleansing, serfdom, the divine right of kings, and extraction of testimony by torture". The long and honourable and often courageous opposition to faith should also be recognized and celebrated and used in the war against unreason.

The religious like to talk about the spiritual world (for the existence of which they can provide no evidence) but they also "make claims about the real world" including, for example, how prayer heals. Since "science and reason can be applied to anything and everything that involves some sort of observation" these claims "are thereby open to scientific testing." It cannot be repeated too many times that, just as for so-called paranormal events, there has never been any satisfactory scientific confirmation of these claims. Stenger disagrees "with the National Academy of Sciences... that science has nothing to say about God or the supernatural. The gods most people worship purportedly play an active role in the universe and in human lives. This activity should result in observable phenomena, and it is observable phenomena that form the very basis of scientific investigation." Less surprising than the Academy's blind spot is the "ignorance of science that is pervasive among theists and theologians" who "try to argue that science operates on faith". Stenger spells it out in terms simple enough for a theologian to understand. "Faith is belief in the absence of evidence. Science is belief in the presence of evidence."

Ah, but absence of evidence does not mean evidence of absence! Actually, sometimes it does. Why isn't there "a single piece of independent historical evidence for the existence of Jesus or the veracity of the events described in the New Testament"? Another huge God-shaped hole is the lack of evidence to support the efficacy of prayer. Together with the straightforward "logical deduction that an omniscient, omnibenevolent, and omnipotent God does not exist given the gratuitous suffering in the world" Stenger concludes "beyond a reasonable doubt that the God worshipped by Jews, Christians, and Muslims does not exist." (See also his excellent God, the Failed Hypothesis: How Science Shows That God Does Not Exist for a fuller treatment.)

So, all those still proselytizing the world over for religion are wasting their time. Why should the rest of us care, if we're lucky enough to live in a secular society? Because not everyone in the world is free from the malign influence of religion and a good humanist value is to reduce suffering where possible. Because nonbelievers are seen as less than human by some believers, and history tells us the fate of some groups so regarded. And because time and again "believers ignore the evidence and make up facts to suit their own prejudices. That's the way faith operates and that's why it should be challenged."