Concerning dirt mice, Maimonides' quote reads:
"the existence of [such a creature] is something well-known..."
The phrase "well-known" strikes me as being a little strong; perhaps in context it is clear that he does not believe in dirt mice, but from the quote the rabbi provided it is not so clear.
Suppose a famous cephalopod researcher were to say, "The harmlessness of bottom trawling is well-known by commercial fishermen, though I cannot explain or comprehend it." I would be inclined to believe there's a good chance that bottom trawling is, indeed, harmless. This is certainly not the case. Maimonides had no right to use such passive language, when he knew very well the likelihood of dirt mice was infinitesimal-- it would topple the foundations of biology. He should have expressed as much but also recommended an investigation; that would be both honest and open-minded.
I believe scientists have a responsibility to voice strong skepticism toward phenomena that violate our understanding of science. Americans are throwing away billions of dollars-- a 1998 figure reports $18 billion-- on alternative medicine. I see chiropractic shops all over the nation, but the procedure is completely unfounded and can actually cause harm, as an orthopedic surgeon I know tells me. Talk to anyone with a legitimate degree in medicine, and they will tell you what a joke herbal medicine, acupuncture, and weight-loss pills are. I believe a "true scientist" should speak with authority, so that vulnerable people will be less likely to fall victim to charlatans.
I agree, thom, that there can be no shortage of spokesmen for science. However, I think it is a bit pretentious for a rabbi to dictate how science should be conducted.