Gary Gutting has spent the course of this year picking the brains of philosophers about religion and non-belief.

Gutting is himself a philosopher and a Catholic who does not see the two as incompatible - "reflective and honest intellectuals" really can believe this stuff, he writes in a previous column for The Stone forum in the New York Times.

His series of interviews with 12 philosophers has been published to The Stone over the last few months and it offers fascinating insights into what his fellow intellectuals make of a whole range of areas, like evolution, what makes people believe, and the case for atheism.

His impetus for the series came from a poll of philosophers in which 73 per cent claimed to accept or be inclined to atheism, compared to 15 per cent who accepted or were inclined to theism, and only 6 per cent who identified as agnostics.

The poll surprised him because he had expected more philosophers to identify as agnostics.

"The question of whether God exists is a controversial one: there have been, and still are, lots of smart, informed and sincere people on both sides. So it would seem that philosophers, committed to rational reflection on the big questions, wouldn't be atheists (or theists) without good reasons," said Gutting, a professor of philosophy at the University of Notre Dame.

"But it is also obvious that the standard arguments for and against God's existence — first-cause arguments, the problem of evil, etc. — have stimulated an enormous amount of debate, leading to many complications but to no consensus.

"Given this, it seemed to me that at least a good proportion of philosophers would be agnostics, undecided about God's existence."

Someone who is very clear about what she believes - and doesn't believe - is interviewee Louise Antony, a professor of philosophy at the University of Massachusetts at Amherst and editor of "Philosophers Without Gods".  She does not only regard theism as unproven, but also as false.

This unequivocal stance is because she feels the question of God's existence has been settled to her satisfaction - meaning she has no doubts.

"I say 'there is no God' with the same confidence I say 'there are no ghosts' or 'there is no magic'. The main issue is supernaturalism — I deny that there are beings or phenomena outside the scope of natural law." 

Rather, she believes people turn towards the idea of religion when they come up against something they can't explain. 

But why is agnosticism not for her?

"I don't say that I'm agnostic because I don't agree with those who say it's not possible to know whether or not God exists.  I think it's possible to know.  And I think the balance of evidence and argument has a definite tilt."

In terms of "evidence", to Antony the "argument of evil" is "overwhelming". 

"That is, I think the probability that the world we experience was designed by an omnipotent and benevolent being is a zillion times lower than that it is the product of mindless natural laws acting on mindless matter," she says.

Tim Maudlin, a philosophy professor at New York University, touches on a related issue when he explains to Gutting that discoveries in cosmology are one of the reasons why he cannot believe that the biblical God was behind the whole universe and that he created it for mankind, as described in Genesis.

"Modern cosmological knowledge has refuted such an account," he said.

"We are living in the golden age of cosmology: More has been discovered about the large-scale structure and history of the visible cosmos in the last 20 years than in the whole of prior human history.

"We now have precise knowledge of the distribution of galaxies and know that ours is nowhere near the centre of the universe, just as we know that our planetary system has no privileged place among the billions of such systems in our galaxy and that Earth is not even at the centre of our planetary system.

"No one looking at the vast extent of the universe and the completely random location of homo sapiens within it (in both space and time) could seriously maintain that the whole thing was intentionally created for us."

On the question of taking a stance on God, Keith DeRose, professor of philosophy at Yale University, argues convincingly that while philosophers may disagree on the existence of God, it's hard to argue that belief or non-belief is irrational.

He says it is not enough to dismiss beliefs in the major religions simply because they come across as bizarre, and because atheists and theists alike have no real way of knowing whether God exists, both sets of belief must be accepted as reasonable.

"My suggestion is that neither theists nor atheists know whether God exists. And here I don't just mean that they don't know for certain, but that they don't know at all," he tells Gutting.

"I don't think the arguments for either theism or atheism lead to knowledge of their conclusions. But there are arguments on both sides from premises that someone might reasonably judge to be plausible. If you find it quite probable that God does not exist, I think it's perfectly possible that you are reasonable to think as you do.

"But this doesn't mean that someone who thinks it is likely that God does exist can't likewise be reasonable in holding that position."

Daniel Garber, in his interview, picks up on the radical shift in ideas since the 17th century when, unlike today, most philosophers - and most people - believed in God.  

There were atheists back then too, he says, but it was something that "in many circles needed a special explanation in a way in which belief didn't".

There's no single factor that changed all of that, but some impactors include the Enlightenment, the Industrial Revolution, Darwinism and the wars of the 20th century.

"As a result science and religious faith have, in a way, exchanged places, and a general and widespread faith in science has replaced the earlier general and widespread faith in God," he said. 

But in Garber's view at least, while God-believing philosophers may be in the minority today, they are not gone completely, and faith and reason are not incompatible. 

"God is not dead among the philosophers. There is still a very significant community of believers among philosophers. I'm personally not one of them, I should say, and I would doubt that they constitute a majority. But even so, I think they cannot be ignored."

This is partly because although science has been claimed by some to have undermined the intellectual basis for belief in God, Garber personally feels religion and theology "cannot easily be refuted" by modern science.

Scientific discoveries have sometimes forced the religions to adapt some of their thinking and interpretations of their own faith, but he does not regard this as a sign that religion is somehow empty.

"I don't underestimate how difficult it is to refute theism," he says.

Interestingly, Garber admits to feeling "convinced that I should want to believe", but it remains for him that he cannot make the step to faith because he sees "no convincing reason to believe".

"I can't believe because I'm not convinced that it is true that God exists. It is as simple as that. Belief is not voluntary, and there are no (rational) considerations that move me to believe that God exists," he says.

"In all honesty, I will admit that I don't have a definitive argument that God doesn't exist either. Which is to say that I refuse to make the judgment that some make that it is positively irrational to believe in God in an objective sense. But without convincing affirmative reasons to believe, I'm stuck.

"If others find reasons that convince them, I'm willing to discuss them and consider them. Who knows? There might be a convincing argument out there, or at least one that convinces me."

Columbia University professor of philosophy and author of "Life After Faith: The Case for Secular Humanism", Philip Kitcher isn't a fan of religious doctrines but he does recognise that a weakness of atheism has been its failure to build community, something religions do very well.

His version of "soft atheism" sees religious practices as something that secularists can learn from and he is also in favour of making common cause with religious movements for the purposes of social justice.

"There is more to religion than accepting as literally true doctrines that are literally false," he says in his interview.

"Humanists think the important achievements of religions at their best — fostering community, articulating and supporting values — should be preserved in fashioning a fully secular world.

"That secular world ought to emerge from a dialogue between humanism and refined religion, one in which religion isn't thrown on the rubbish heap but quietly metamorphoses into something else."

That doesn't mean the faithful should necessarily see him as an ally.  He admits that he might indeed be a more "insidious foe" than outspoken atheist Richard Dawkins because "instead of ignoring important species of religion, I want to prepare the way for their gradual disappearance".

Rounding up his own thoughts on the series, Gutting points out the limits of scientific evidence as an argument against the existence of God.

"[Atheists] can't just keep saying 'there's no empirical evidence' and think they've shown that a theism based on metaphysical reasoning or nonempirical experience is irrational," he said.

"The core question is whether there is anything beyond the empirical — some transcendent reality we can call God. I think it can be rational to say there isn't a transcendent reality.

"But to show that it's irrational to say there is, you'd have to end the impasse in philosophical discussions of theism. That's where atheism falls short and agnosticism is the preferable position."

But he also suggests Christians need to sharpen up their arguments.

"There's nothing in the Bible that presents God as a well-confirmed scientific hypothesis, and there's a great deal that emphasises that the truths of religion are beyond human comprehension," he says.

"In spite of this, believers too often play the double game of insisting on God's transcendence and mystery to meet rational objections, but then acting as if they'd justified a straightforward literal understanding of their beliefs."

In the end, he agrees with Kitcher that the greatest obstacle facing atheism today is the absence of strong communal practices that characterise religions.

"People need to believe something that provides a satisfying a way of living their lives, and most people need to find this in a community. So far atheism has produced nothing like the extensive and deep-rooted communities of belief that religion has."