does belief in god harm us?

Recently I visited a web forum conducted by atheists. Its home page had a slogan: "Believe in God? We can fix that!", so I posted a question - "I believe in God. Why does that need fixing, and how do you propose to do it?"

Of course some interesting discussion ensured, some of which was based around the answers some of the atheist members gave to the first part of my question. They argued that my belief needed fixing because it was harmful to me and to the world. But they gave very little evidence for this claim, so I set myself to test the proposition: Belief in God leads to worse outcomes in the world than non-belief.

To demonstrate that the proposition is true would require four things to be established:

(1) Have theists done worse things in the world than non-theists?

For this we need an overall estimate of the evil things done by both sides, based on competent, objective research.

Killings is one measure of general evil (not the only one, but useful because there are good estimates available). The following 5 references seem to me to be competent and objective estimates of killings committed by various groups over the centuries:

Which has killed more people? Genocides (Wikipedia) 20th century death tolls World War II death count Historian Rodney Stark

It turns out that the number of killings by non-theists in the 20th century alone was estimated to be 75-100 million, much more than the estimated 30 million committed by christians in 20 centuries. These numbers are enough for anyone to be deeply ashamed of, but they definitely suggest the atheist proposition falls at the first hurdle.

(2) Are theism and non-theism significant causes of these atrocities?

This is a pretty difficult one to test, because how can we judge whether the religious belief of someone committing an atrocity is genuine, or whether it was atheism or communism that led to atrocities? But if we want to make an assessment, we have to be circumspect, and rely on good historians.

• Sociologist and historian Rodney Stark concludes that governments and not the church were clearly responsible for the millions who died in the European conquest of the Americas (where a large number of killings occurred), and that atheism was probably not the main factor in the millions of deaths under Chinese and Russian communism.
• Nevertheless, atheism was an integral part of Marx-Leninism as this book outlines. It talks of "Lenin's policy of militant atheism". Lenin sent a letter in 1922 where he said that the "protracted use of brutality" was necessary to achieve the promotion of atheism.
• The following references report on research indicating that religion was not a major factor in most recent suicide bombings (contrary to popular belief): The role of social context in terror attacks Is Suicide Terrorism Religiously Motivated? On the Edge

So the evidence is not totally consistent, but tends to oppose the proposition that it is the religious beliefs that cause the atrocities; rather it seems to be political beliefs.

(3) Is the record of theism and non-theism in the past a reliable indication of the likely behaviour today?

Even if we could establish that either theism or non-theism did evil things in the past, it is the present we are living in, and in which the proposition is being applied. Are things likely to be the same, or different?

This is even harder to gather evidence on. But perhaps where social and international conditions now are similar to when the atrocities were committed, then we may be able to demonstrate some connection between the past and the present. On this basis, Muslim suicide bombing is obviously current, as are thousands of executions a year in China by an explicitly anti-religious Government, far more than for any other country (see Amnesty International figures for this). Next closest in time and social conditions would be the communist killings of the 20th century, with the christian killings of the invasion of South America, etc, obviously from a world very different to today.

It seems that, overall, belief in God is likely to do less harm today than in the past.

(4) How do the beneficial effects of theism compare to the beneficial effects of non-theism?

So far we have only considered evil, but good must also be in the equation.

In history, christians have been at the forefront of much beneficial social reform such as hospitals, education, anti-slavery, etc. Rodney Stark concluded from his study of the rise of christianity in the first few centuries CE that one of the major factors was the christians' superior record in social welfare (there are independent letters of an unsympathetic Roman emperor to demonstrate this), especially in their care of women, children and orphans.

In the present day, many independent studies  show that believers have better mental and physical health and general wellbeing, lower rates of addiction and suicide, lower levels of stress and depression, and recover from surgery more quickly. They also are much more active in community service roles and much more likely to give time and money to charities (for Australia, see new generations and religious belief, for the US see this study). And in Australia, christian groups are by far the largest non-government providers of social services (especially aged care, but also crisis help, dealing with addictions, etc).

This research is summed up in this telling article, "Faith does breed charity" by atheist journalist Roy Hattersley, who concludes: "The correlation is so clear that it is impossible to doubt that faith and charity go hand in hand..... The only possible conclusion is that faith comes with a packet of moral imperatives that, while they do not condition the attitude of all believers, influence enough of them to make them morally superior to atheists like me. The truth may make us [atheists] free. But it has not made us as admirable as the average captain in the Salvation Army."

So on this matter, the evidence again does not seem to favour the atheist proposition.

so what may we conclude?

Sadly, people have done many evil things to each other, but it appears that belief or disbelief in God are not the major cause of this. We probably can't say for sure that either belief or disbelief in God are likely to lead to bad outcomes, but the evidence tends to suggest that believers contribute more good to society and have done less harm than have non-believers in the past.