"Atheism is the default position in any scientific inquiry, just as a-quarkism or a-neutrinoism was. That is, any entity has to earn its admission into a scientific account either via direct evidence for its existence or because it plays some fundamental explanatory role. Before the theoretical need for neutrinos was appreciated (to preserve the conservation of energy) and then later experimental detection was made, they were not part of the accepted physical account of the world. To say physicists in 1900 were “agnostic” about neutrinos sounds wrong: they just did not believe there were such things."
Modern Cosmology Versus God's Creation - NYTimes.com