The following article appeared in the March 17, 2012 "God issue" of New Scientist.
The party line among scientists -- believers and nonbelievers alike -- is that science and religion are what Stephen Jay Gould called "non-overlapping magisteria." In 1998 the US National Academy of Sciences issued a statement asserting "Science can say nothing about the supernatural. Whether God exists or not is a question about which science is neutral."
Yet according to a survey the same year, 93 percent of the members of the academy do not believe in a personal god.
Since about the same percentage of all US citizens say they do believe in a personal god, it makes one wonder what, if not their science, leads the elite of US scientists to differ so dramatically from the general population.
A majority of scientists at all levels do not believe in any god. Yet most are unwilling to challenge the religious beliefs of others. I am a physicist who, along with others dubbed the New Atheists, is willing to challenge religious belief. The gods worshipped by billions either exist or they do not. And those gods, if they exist, must have observable consequences. Thus, the question of their existence is a legitimate scientific issue that has profound import to humanity.
We can consider the existence of god to be a scientific hypothesis and look for the empirical evidence that would follow. Many of the attributes associated with the Judaic-Christian-Islamic God have specific consequences that can be tested empirically. Such a God is supposed to play a central role in the operation of the universe and the lives of humans. As a result, evidence for him should be readily detectable by scientific means.
If a properly controlled experiment were to come up with an observation that cannot be explained by natural means, then science would have to take seriously the possibility of a world beyond matter.
In fact scientists have empirically tested the efficacy of intercessory prayer -- prayers said on behalf of others. These studies, in principle, could have shown scientifically that some god exists. Had they found conclusively, in a double-blind placebo-controlled trial, that intercessory prayers heal the sick, it would have been difficult to find a natural explanation. They did not.
Similar tests have been done on near-death experiences (NDEs). Some people having an NDE during surgery have reported floating above the operating table and watching everything going on below. Whether this is a real experience or a hallucination can be tested easily by placing a secret message on a high shelf out of sight of the patient and the hospital staff. This has been tried, and no one reporting an NDE has yet to read the message.
Just as science can design experiments to test the existence of God, it can also seek evidence against a god's existence in the world around us. Here we must be clear that we are not talking about evidence against any and all conceivable gods. For example, a deist god that creates the universe and then just leaves it alone would be very hard to falsify. But no one worships a god who does nothing.
If God is the intelligent designer of life on Earth, then we should find evidence for intelligence in observations of the structure of life. We do not. The Intelligent Design movement failed in its effort to prove that the complexity found in some biological systems is irreducible and cannot be explained within Darwinian evolution. Life on Earth looks just as it should look if it arose by natural selection.
Most religions claim that humans possess immaterial souls that control much of our mental processing. If that were true, we should be able to observe mentally induced phenomena that are independent of brain chemistry. We do not.
If God is the source of morality, then we should find evidence for a supernatural origin in human behavior. We do not. People of faith behave on average no better, and in some cases behave worse, than people of no faith. History shows that the moral and ethical guides that most of us live by did not originate with the monotheistic religions, as proponents of those religions would have us believe. Instead, moral behavior appears to have evolved socially.
Again, if God answers prayers, we should see miraculous effects of prayer. With millions of prayers having been said every day for thousands of years, we would expect some to have been answered by now in a verifiable way. They have not.
If God has revealed truths to humanity, then these truths should be testable. Over the millennia many people have reported religious or mystical experiences in which they have communicated with one god or another. By now, we should have seen some confirming evidence for this, such as a verifiable fact that could not have been in the person's head unless it was revealed to them. We have not.
If God is the creator of the universe, then we should find evidence for that in astronomy and physics. We do not. The origin of our universe required no miracles. Furthermore, modern cosmology suggests an eternal "multiverse" in which many other universes come and go.
If humans are a special creation of God, then the universe should be congenial to human life. It is not. Theists claim that the parameters of the universe are fine-tuned for human life. They are not. The universe is not fine-tuned for us. We are fine-tuned to the universe.
After evaluating all the evidence, we can conclude that the universe and life look exactly as they would be expected to look if there were no God.
Finally, I would like to comment on the folly of faith. When faith rules over facts, magical thinking becomes deeply ingrained and warps all areas of life. It produces a frame of mind in which concepts are formulated with deep passion but without the slightest attention paid to the evidence. Nowhere is this more evident than in the US today, where Christians who seek to convert the nation into a theocracy dominate the Republican party. Blind faith is no way to run a world.