There Ain't No Such Thing!
"There ain't no such thing!"
This is a familiar sentiment to Orthodox Jews with rationalist leanings who have spent a long time in yeshivah. Whether the rebbe is telling you about mermaids, humanoids growing from the ground via a cord attached to their navel, or impossibly large animals, the modern and educated student has a hard time believing that such things exist.
"An albino cyclops shark?! There ain't no such thing!"Yet the question itself is often rebuffed as an act of heresy. Sometimes, this is directly because of the prestige of the authority that is being challenged. In other cases, it is because of the prestige being given to science that is considered unwarranted. In those cases, the questioner is often rebuffed with phrases such as "scientists don't know everything," "scientists don't know anything," or "you can't prove a negative - you can't prove that something doesn't exist!"
It is therefore valuable to see the following comments of R. Yom Tov ben Avraham Asevilli, better known by his acronym Ritva. The subject is a mysterious fish in the Gemara, Avodah Zarah 39b, named a kilbit. Rashi identifies it as a fish that is spontaneously generated inside vats of fish-juice - but Rashi notes that it is only generated from the juice of kosher fish, and if there is juice of non-kosher fish mixed in, the kilbit will not appear. Ritva objects to this:
"This explanation is exceedingly difficult - first, it is not logical that there is such a thing, and it does not exist in nature."
This is a perfect expression of the rationalist inclination. The existence of such a creature does not make sense, and furthermore there does not appear to be empirical evidence of such a creature.
(At first, I was bothered by this comment of Ritva. After all, belief in spontaneous generation was perfectly normative throughout the medieval period. But there are two possibilities. First, we see that Rambam, while insisting on the reality of spontaneously generating insects, was skeptical of the possibility of spontaneously generating mice, presumably because it is a larger and more complex creature. Second, it could be that Ritva is not objecting to the spontaneous generation of this fish per se, but rather to the aspect of it only spontaneously generating from the juice of kosher fish.)
So would Ritva's comment be good ammunition for those seeking to defend the rationalist approach to their non-rationalist teachers? Of course not. The inevitable rejoinder would be "But you're not Ritva! He could say it, but you cannot!"
(Reminder: I am travelling to New York tonight, then to LA next week. If you would like to meet or join parlor meetings in support of the Biblical Museum of Natural History, please be in touch!)