One of the biggest controversies to ever hit the modern religious world revolved around the banning of the books of Rabbi Nathan Slifkin, also known as the “Zoo Rabbi.”

At the time a loyal, though perhaps somewhat naive graduate of the mainstream Chareidi (“Ultra-Orthodox”) “Midrash Shmuel” Yeshiva, he had written some fascinating books on animals in the Tanach and Talmud as well as the often related subject of Science and Torah.

The young and talented Rabbi was totally unprepared for the tsunami of condemnation and eventual book-banning that was to be unleashed on him from some of the most senior Talmidei Chachamim (Torah scholars) in the Chareidi world- some of the main alleged crimes : suggesting that Chazal (our sages) sometimes erred on scientific matters as well as that the age of the universe and the story of creation did not need to be taken literally.
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It is important to note that these suggestions were not his own, but were based on earlier authorities, among them some leading Rishonim and Achronim.

One of the leading Yeshiva Heads in the Israeli Anglo Chareidi world, haRav haGaon Moshe Meiselman wrote a very large almost encyclopedic book, “Torah, Chazal, and Science” in order to refute these ideas and support the condemnations, and article upon article has been written since refuting and counter-refuting the bans.

An entire movement to restore the “Rationalist Judaism” approach of the Rambam and others that this ban seemed to have condemned together with the books was started by Rav Slifkin, and many old ghosts in the centuries of debate on the subject have been reawakened, for better or for worse .

I am generally in favor of giving the benefit of the doubt to anything an expert Talmid Chacham says, even if I disagree personally, and as Bnei Torah, we are obligated to try our best to understand the words of all Gedolei Yisroel ( great Torah scholars of Israel)

As such, and given that the subject and its many ramifications held a lot of personal interest to me as well, I spent a lot of time back then collecting information on the subject and trying to make some sense of it myself, in the way I received from own Rabbis, namely by starting with the primary sources themselves .

I do not wish to take a stand one way or another in this forum regarding who was right, but one thing I am pretty certain of after my own studies is that we are dealing with two very different legitimate approaches amongst the earlier authorities, which while perhaps not as binary as some believe, are certainly extremely difficult if not impossible to reconcile.

I also do not believe that this debate has anything to do with whether Chazal could be wrong or not.
It is clear and undebatable that Chazal could theoretically make mistakes- even the greatest humans can!

The masechta of Horayos and its related pessukim in Vayikra deals specifically with members of the great Sanhedrin, the greatest of the great, making mistakes.
Even Moshe Rabbeinu, whose level of prophecy was qualitatively and quantitatively in a different league to all prophets- פה אל פה אדבר בו – made mistakes, for which he was ultimately denied his life’s dream of entering Eretz Yisroel.

The debate seems to be more over how to relate to an apparent conflict between our observed reality, as described by science, and reality as Chazal describe it.

Whereas those described as “rationalists” would tend to take observed science as a given and assume that Chazal simply were not privy to these observations, those who subscribe to the principle that everything that Chazal said was guided by some form of divine inspiration or assistance, would tend to assume that our scientific observations are simply based on faulty science or powers of observation and Chazal always get the benefit of the doubt .

On our daf, we are thrown right in the deep end, with the debate between Rabbi Eliezer and Chachamim whether can is liable for killing lice on shabbos.

Killing a living creature is generally forbidden under the melacha if נטילת נשמה (taking a life,) which falls under the category of שוחט, (slaughtering).

Why then should there be a distinction between lice like creatures and other living creatures?

Rav Yoseif concludes that this is because of the general rule that a forbidden shabbos melacha must resemble what was done in the work of the Mishkan.

Rabbi Eliezer holds that being a living, mortal creature is itself enough of a similarity to the rams that were slaughtered for their skins to be used in the mishkan, to be include
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The Chachamim, on the other hand, hold that the similarity has to be more precise- it has to be a living creature that reproduces, just
like the rams in the mishkan.

The Gemara explains that seeing as lice do not reproduce, the Chachomim do not include them in the prohibition.
Before we proceed, we really should try understand why the ability to reproduce should be so significant that it puts creatures that do not do so in a totally different category to those that do. Why is this function any more significant than being able to run or fly or swim or produce live young?

It seems that the reproductive function is not just any other function of the body, but according to Chachamim part of the essential definition of what a living species is about.
A species without that function is thus although still technically a living creature, qualitatively an entirely different type of creation and cannot be compared to the rams of the mishkan.

Given that in modern biology, one of the main definitions of life is the ability to reproduce, at least on the cellular level, this seems even more fascinating.

One should note that this requirement applies to the species as a whole- there is no suggestion here that an animal or person who as an individual is not able to reproduce is considered any less “living ” than one who can.

Anyone who has read the sugya until here must surely be bothered immediately by the assumption of the Gemara that lice do not reproduce.
Firstly, anyone with children know what an issue it is to get rid of lice, how their eggs(nits) are particularly resistant to removal, and how they certainly reproduce from one louse to enough to literally crawl all over one’s hair
Secondly, any junior biology student knows that all living species reproduce.

How could Chazal possibly say something which every school child today knows is completely incorrect?
Furthermore, even if we accept the “rationalist” claim that much of modern science was not known to Chazal and that they based their claims and halachik decisions on the science of time, surely anyone was able to notice the nits that almost always accompanied hair lice and that they eventually hatched into lice ?

Rav Slifkin and many others have gone to great lengths to point out, however, that this claim was not unique to Chazal, but was in fact the commonly accepted view amongst scientists, philosophers, and the masses until very recently in history, when Louis Pasteur proved that even microorganisms do not generate spontaneously but have to be able to be generated by “parents” of their own type .
Not only lice, but certain worms, and even rodents were believed to generate spontaneously from sand, sweat, air, or rotting food, and the connection between nits and lice, as incredible as it sounds, does not yet seem to have been made .

In the absence of any evidence to the contrary, or any tradition to the contrary, why would Chazal not have made this assumption, the same way that they seem to have assumed that a flat circular earth was the center of a spherical universe and the sun and stars moved around it?

The continuation of the sugya, however, makes it clear that Rav Yosef’s student, Abaya did indeed question this almost universally accepted assumption that lies did not reproduce, and made the connection, at least in passing, between nits and lice.
It also seems he did this not based on their own observations, which do not seem to have been any superior in this regards to that of conventional wisdom, but based on an earlier statement of Chazal (the Amora Rav in Avoda Zara 3b) which implies that lice do in fact hatch from eggs!

At this stage, it seems, at least on a superficial reading, that chazal had correct biologically information which was not known to contemporary science and questioned the science of their times based on that.

However, the Gemara seems unwilling to concede that contemporary science was wrong, and instead interprets the earlier as referring not to lice eggs, but to an entirely different species, called the eggs of lice.

Are we seeing later Amoraim themselves resorting to a forced interpretation of an earlier authoritative statement in order not to contradict the contemporary science of their time?