Wednesday, July 19, 2006

Spontaneous Generation in the Talmud

Must we believe that spontaneous generation of lice occurs, or that it did, at least, during Talmudic times? Many claim we must, pointing to the fact that in this instance, there is a drasha (kind of; see Shabbat 107b) that discusses spontaneous generation, and we can't invalidate a drasha. Some (I believe Rabbi Shlomo Zalman Auerbach, for example, as well as Rabbi Shlomo Fisher, in Derashot Beit Yishai, siman #47, fn. dalet) suggest Chazal really meant just that the reproduction of lice is not visible to the naked eye, and therefore is not recognized from a halachic perspective; but that they were not, in fact, contradicting the modern understanding of how a louse forms. I'm uncomfortable with this explanation; how are lice different from other insects in this regard? Also, the fact that the entire ancient (and medieval) world believed in spontaneous generation is quite suggestive.

I think we can preserve the validity of the drasha even if we think that Chazal were wrong about spontaneous generation of lice. The drasha (look at it carefully - Shabbat 107b), according to those who argue with Rabbi Eliezer, says that a species must reproduce, like the eilim me'odamim, in order for killing it to be prohibited on Shabbat. It doesn't specify lice. A Talmudic rabbi who thought that lice didn't reproduce would, indeed, derive from this drasha that killing lice is not prohibited mide'oraita, but the faulty science involved in his conclusion would reside exclusively in his application of the drasha, not in the drasha itself. And if the actual drasha doesn't assume that lice are reproduced spontaneously, then we are not obligated to do so either.

But why would there be a drasha about species that don't reproduce, if all species do reproduce (as per modern science)? Doesn't the drasha, regardless of whether it's really talking about lice, clearly endorse the notion that spontaneous generation of animals does occur? It does seem to, but I don't think that's at all in conflict with modern science; in fact, I think it can be explained using modern science. Modern medicine and biotechnology perform new wonders on a regular basis. There is now very serious talk of growing people extra sets of organs, to be used in case the originals need replacement. Such procedures are already in place for some organs. Animal cloning has been done. Test-tube fertilization has been done. Genetic modification has been done. Biologists can create all sorts of amazing things in today's laboratories. Is it far-fetched to think that one day they will be able to make animals "from scratch" (if, indeed, they can't already do it today)? I think that if science wants to, it will definitely be able to make, let's say, a louse, from a bunch of inanimate matter. Would one be permitted to kill such a louse (or fly, or deer) on Shabbat? Mide'oraisa, yes - that's what it says at Shabbat 107b. It may thus be that the drasha, far from being scientifically backward, is actually forecasting a level of scientific sophistication that man has only recently begun to see as within the realm of the possible.

10 comments:

Rael Levinsohn said...

It is axiomatic to this discussion that Chazal cannot err with regard to the drashas on pesukim.

Where does some an assumption come from? Why can Chazal not have made a drasha on the passuk based on their knowledge at the time, and yet the drasha still stinds because we do not have the halachic mechanism to discount it, regardless if the "factual" basis of it is now thought to be incorrect?

Also where does it say that Chazal were always "spot on" with their drashot?
Dont halachic authorities err? Some sources would be greatly appreciaited.

Rael Levinsohn said...

I found this online earlier today, I have not read it yet, but it seems interesting.

http://www.chabad.org/library/article.asp?AID=112226
It is a whole book based on the Lubavitcher Rebbe ZT"L view on science related issues. I just skimmed and I saw something about spontaneous generation.

He Who Must Not Be Named said...

It is axiomatic to this discussion that Chazal cannot err with regard to the drashas on pesukim.

Where does some an assumption come from? Why can Chazal not have made a drasha on the passuk based on their knowledge at the time, and yet the drasha still stinds because we do not have the halachic mechanism to discount it, regardless if the "factual" basis of it is now thought to be incorrect?

Also where does it say that Chazal were always "spot on" with their drashot?
Dont halachic authorities err? Some sources would be greatly appreciaited.


Good questions. You may be right. I would like to look into it.

He Who Must Not Be Named said...

Please note that I originally attributed to Rabbi Shlomo Fisher an opinion he does not express. I have now corrected the error. Thanks to DH for pointing it out.

Anonymous said...

A simple explanation for the "spontaneous generation" of lice may be the need for a blood meal. Note that Chazal define the "spontaneity" if you will, as not being born from "zachor u nekava". Lice and mosquitos are notable for needing a blood meal in order to generate a large number of eggs. After normal fertilization by a male, a female without a blood meal will lay very few, if any, eggs. After a blood meal, the number of eggs laid skyrockets. Also, a fertilization in the beginning of the summer will suffice for the entire season. So a randomly captured louse or mosquito would look as if it were spontaneously (without the need for a male) generating.

Freelance Kiruv Maniac said...

The first solution above does not at all avoid the male-female eproduction issue at all.
The second solution cannot work in light of the gemara Bechoros citing Chazal's awareness of YEARS long gestation period of certain snakes.
So a fertilization lasting only one season is a non-starter.

Freelance Kiruv Maniac said...

I think the solution of He who must not be named is quite Slifkin/Kaplan-esque.
Did you read the last chapter in Mysterious Creatures and his solution to the dirt mouse? It is very similar to yours here.

Its nice, but a little ad hoc. You are still saying the Chacmei Hatalmud were misled by the science of his time to allow what is essentially Chillul Shabbos for untold generations.
This is beyond credulity from a traditional POV.

He Who Must Not Be Named said...

The first solution above does not at all avoid the male-female eproduction issue at all.

I'm not sure what you mean. What is the "first solution"? Rabbi Auerbach's?

He Who Must Not Be Named said...

The second solution cannot work in light of the gemara Bechoros citing Chazal's awareness of YEARS long gestation period of certain snakes.
So a fertilization lasting only one season is a non-starter.


I don't understand your point here either. I'd be obliged if you'd elaborate.

He Who Must Not Be Named said...

You are still saying the Chacmei Hatalmud were misled by the science of his time to allow what is essentially Chillul Shabbos for untold generations.
This is beyond credulity from a traditional POV.


1. It wasn't (/isn't) chillul Shabbos for anyone who, using the proper halachic process, paskened that killing lice was (/is) mutar.

2. What leads you to believe the proposed solution is "beyond credulity from a traditional point of view?"

3. What leads you to believe the proposes solution is factually incorrect?