Halacha, Science, and Birds

A New Case of Science Contradicting Halacha?

There aren’t so many cases of halacha being based on scientific error, and those that exist are fairly well known. Most famous is the Gemara’s permission to kill lice on Shabbat based on the mistaken belief that they spontaneously generate. In my book Sacred Monsters, I discussed various approaches that are taken. Some take the position that the halacha should be changed accordingly. But others (with whom I strongly agree) take the approach that the halacha remains in place.

The reason is that the halachic authority of the Gemara was canonized; we follow it even though in rare cases it may be based on mistaken beliefs. This is similar to the celebrated case of the oven of Achnai, where the objectively correct view - as attested by none other than God Himself - was overruled in favor of the majority. And the reason for this in turn is that stability is a crucial component of halachic authority. Such stability comes in some cases from following the majority, and it also comes from canonizing certain authorities and texts. (The only exception is for cases where human life is at stake; thus, we do not follow the Gemara’s position that an eight-month fetus is less viable than a seven-month fetus, or that one may not clear away rubble on Shabbos to rescue someone who is not breathing.)

But we have another case to add to the discussion. The other week, I wrote a post about identifying kosher birds. Rashi has an understanding of this topic which leads him to require a mesorah in order to eat a bird. Ramban and the majority of Rishonim, on the other hand, observe that Rashi’s view is empirically proven wrong, and instead follow Rav Moshe bar Yosef and only require a bird to have three kosher characteristics in order to be permissible. The Shulchan Aruch, however, adopts Rashi’s view, albeit with some exceptions, and the Rema adopts it fully.

So, what we have here is an interesting case of halacha being based on a mistaken belief rather than the correct empirical observation. Does this mean that the Rema’s view should be rejected? Or, like Chazal, has Rema been canonized, at least for Ashkenazim?

It is clear that Rema has not been canonized in anything like the same way as Chazal. There are plenty of later rabbinic authorities who dispute the rulings of Rema and thus did not see his rulings as authoritative. And accordingly, there are cases in which Ashkenazim do not follow Rema’s rulings.

The case of bird kashrut is one where a prominent halachic authority disputes Rema. But it’s not that he overrules him, per se; rather, it’s that he argues that this ruling of Rema is not only based on scientific error, but was also evidently never accepted in the first place.

R. Yosef Shaul Nathanson (Responsa Sho’el u’Meshiv 5:1:69). argues that the primary and empirically correct halachic view follows Rav Moshe bar Yosef rather than Rashi; accordingly, as long as a bird possesses the signs of a kosher bird it may be eaten, and no mesorah is required. And he further argues that almost everyone surely agrees, because almost everyone eats turkey, which does not have a mesorah! He notes that the acceptance of turkey itself proves that this is the accepted ruling, and that Rashi's stringency is not to be followed.

In fact, there can be other reasons to justify turkey. Still, what is relevant is that R. Nathanson certainly did not see Rema’s view as canonized, and invoked its empirical errors to argue that it need not be accepted.

Now, the Biblical Museum of Natural History’s “Feast of Kosher Curiosities” is coming up soon. You might think that in line with Rav Moshe Bar Yosef’s view, I would be arranging to serve all kinds of exotic birds that have the three kosher signs (there are many hundreds of such species!). However, I’m not doing that. The reason is that there is “absolute” canonization and “effective” canonization (I’m not sure that I’m using the best choice of words here, but I couldn’t come up with anything better).

It’s true that Rema was not canonized. Nevertheless, his rulings were widely accepted to the point that there is widespread belief that they were universally accepted, and those who argued with him were generally only very prominent halachists. Flagrantly disregarding Rema’s ruling, even though it’s generally considered to be a mere stringency, even though most Rishonim reject it, even though it’s based on an error, and even though R. Nathanson endorses rejecting it, would be problematic.

Being an Orthodox Jew means upholding the authority of the canonized Talmud. Being an Orthodox Ashkenazi Jew also means, to a certain extent, upholding the authority of Rema. Even though there are many situations in which we do not follow Rema, we should be reticent of coming up with new cases for disputing him. I have heard Rav Schachter say that since Rema’s position here is only a stringency, it can be set aside when there is another halachic factor to take into account. But it was only when there is some additional halachic factor to take into account. Otherwise, we should follow Rema.

Fortunately, even within the confines of following Rema, there are more species of birds available for eating than are commonly assumed! (But not the bird from my garden aviary pictured above.) In particular, there is something that may come a a particular surprise. All shall be revealed at the Feast of Kosher Curiosities. It’s 80% sold out, so book soon!