To be fair, a 'proof' that is directly experienced and scientific proof are both wholly different from a mathematical proof, which is simply a sequence of deductive steps originating from a stipulated set of axioms and definitions. Given a rational person who also happens to be a creationist, even he would agree that assuming

then B is provable in this system. This is in contrast to scientific inquiry, where there are no axioms. Instead, there are measurements and observations, and hypotheses are created which attempt to explain the measurements and observations. If a hypothesis is successful in its explanatory or predictive power with respect to further measurements and observations, eventually we may call it a theorem. At no point did we prove the hypothesis in the mathematical sense, and in fact if there came along a measurement or observation that contradicted the theorem, it would have to be revised or discarded.

Demanding to see more data before accepting a scientific theory is not an unscientific thing to do, as long as one does it honestly and with intellectual integrity. Obviously the gotcha arguments thrown around by many creationists concerning the inability to directly collect data from before the dawn of man doesn't really fulfill the spirit of science...