"This argument is a retreat to discredited empiricism-if you can't see it, it must not exist."
Actually, empiricism is not discredited. It's most basic concept is that the data should dictate conclusions, not biases or paradigms or metaphysical preconceptions. This is still the basic view of science today. However, the form of empiricism you describe - called empirical literalism by SJ Gould - has been discredited because it was too limited. In Gould's own words ("The Stinkstones of Oeningen," _Hen's Teeth and Horse's Toes_, pg. 105), it advocated that scientists only "believed what they saw, interpolated nothing, and read the record of the rocks directly [his article dealt primarily with geology]." However, since "[r]aw empirical literalism will not adequately map a complex and imperfect world", it often becomes necessary to employ "a more subtle and _less_ empirical method: use reason and inference to supply the missing information that imperfect evidence cannot record." In other words, if we believed only what we saw in creation, we would miss or ignore most of what c
reation had to tell us.
Kevin L. O'Brien
"Good God, consider yourselves fortunate that you have John Adams to abuse, for no sane man would tolerate it!" William Daniels, _1776_