The recent debate about Barack Obama’s nominee Dr. Francis Collins as the next director of the National Institutes of Health highlights a problem that is seldom discussed within philosophy of science. One leading opinion within the philosophy of science seems to be that in order for someone to be a good scientist or philosopher of science, one has to be at least an agnostic, if not an atheist. The general idea seems to be that it is absolutely irrational to believe in some higher being whose existence cannot be proven, and to be a good and dedicated scientist at the same time. The deeper reason for that idea seems to be that scientists that do believe have an “easy way out” if they encounter a difficult problem. This accusation is especially made towards the proponents of Intelligent Design who claim to have an equally good explanation for how the world came about as those who are proponents of the Evolutionary Theory do. From my point of view Intelligent Design is irrational and by applying the criteria used to distinguish good and valid scientific theories from unscientific ones one can even show why. However, it seems equally irrational to maintain that all good scientists have to be atheists. There is no compelling argument why someone who believes in some form of higher being is any less inclined to scientifically explain how the world came about, than someone who does not.
For those interested in the Dr. Collins debate, the article from the New York Times can be found here
Intelligent Design
By William Hasker , Huntington University
(Vol. 4, March 2009)
Philosophy Compass
The Philosopher's Eye 
Um, no. People are upset about Collins not because he is a believer, but because he is a believer who has explicitly argued that science has no business investigating human nature, and is on record as saying that atheists cannot be moral.
There’s an interesting issue here independent of the Francis Collins political debate. Can folks be irrational in one domain but not others? Clear answer: yes. So someone can be foolishly theistic without being a poor scientist. Is irrationality in one area evidence for irrationality in other areas? Not so clear. I think the answer is ‘yes,’ but the evidence is weak and defeasible.