http://lesswrong.com/lw/i8/religions_claim_to_be_nondisprovable/The earliest account I know of a scientific experiment is, ironically, the story of Elijah and the priests of Baal.
The people of Israel are wavering between Jehovah and Baal, so Elijah announces that he will conduct an experiment to settle it - quite a novel concept in those days! The priests of Baal will place their bull on an altar, and Elijah will place Jehovah's bull on an altar, but neither will be allowed to start the fire; whichever God is real will call down fire on His sacrifice. The priests of Baal serve as control group for Elijah - the same wooden fuel, the same bull, and the same priests making invocations, but to a false god. Then Elijah pours water on his altar - ruining the experimental symmetry, but this was back in the early days - to signify deliberate acceptance of the burden of proof, like needing a 0.05 significance level. The fire comes down on Elijah's altar, which is the experimental observation. The watching people of Israel shout "The Lord is God!" - peer review.
And then the people haul the 450 priests of Baal down to the river Kishon and slit their throats. This is stern, but necessary. You must firmly discard the falsified hypothesis, and do so swiftly, before it can generate excuses to protect itself. If the priests of Baal are allowed to survive, they will start babbling about how religion is a separate magisterium which can be neither proven nor disproven.
--snip--
In contrast, the people who invented the Old Testament stories could make up pretty much anything they liked. Early Egyptologists were genuinely shocked to find no trace whatsoever of Hebrew tribes having ever been in Egypt - they weren't expecting to find a record of the Ten Plagues, but they expected to find something. As it turned out, they did find something. They found out that, during the supposed time of the Exodus, Egypt ruled much of Canaan. That's one huge historical error, but if there are no libraries, nobody can call you on it.
The Roman Empire did have libraries. Thus, the New Testament doesn't claim big, showy, large-scale geopolitical miracles as the Old Testament routinely did. Instead the New Testament claims smaller miracles which nonetheless fit into the same framework of evidence. A boy falls down and froths at the mouth; the cause is an unclean spirit; an unclean spirit could reasonably be expected to flee from a true prophet, but not to flee from a charlatan; Jesus casts out the unclean spirit; therefore Jesus is a true prophet and not a charlatan. This is perfectly ordinary Bayesian reasoning, if you grant the basic premise that epilepsy is caused by demons (and that the end of an epileptic fit proves the demon fled).
Not only did religion used to make claims about factual and scientific matters, religion used to make claims about everything. Religion laid down a code of law - before legislative bodies; religion laid down history - before historians and archaeologists; religion laid down the sexual morals - before Women's Lib; religion described the forms of government - before constitutions; and religion answered scientific questions from biological taxonomy to the formation of stars. The Old Testament doesn't talk about a sense of wonder at the complexity of the universe - it was busy laying down the death penalty for women who wore men's clothing, which was solid and satisfying religious content of that era. The modern concept of religion as purely ethical derives from every other area having been taken over by better institutions. Ethics is what's left.
http://lesswrong.com/lw/i8/religions_claim_to_be_nondisprovable/------------------------------------------
A very, very long list of other really great posts by this author...
http://www.cs.auckland.ac.nz/~andwhay/postlist.html