Wherefore by their fruits shall ye know them - Mat 7:20
This is the basis of scientific observation, laid out by Jesus himself. Although he was referring to false prophets at the time (teachers of false belief), the principle is the same. Observation of the results disclose the nature of the cause. Evolutionists, whether they acknowelege it or not, are attempting to apply this religious principle to their theories. I just don't think they are doing so properly, and nothing they argue hs convinced me otherwise (I'm an ex evolutionist, BTW).