An oft-cited example of the ability of the Sages to extract scientific knowledge from the Torah is the case of snake gestation.
(The gestation period for) a snake is seven years… How do we know this? Rav Yehudah said in the name of Rav…: As it says, “You are cursed from all the domestic animals and from all the beasts of the field” (Bereishis 3:14). If the snake is cursed from all the domestic animals (which have a gestation period of at least five months), then all the more so it is cursed from the wild animals (whose minimum gestation period is 52 days)! Rather, it tells you that just as a domestic animal is cursed seven times more than a wild animal – i.e., the donkey (which has a gestation period of one year) and the cat (whose gestation period is one-seventh that of the donkey) – so too is the snake cursed seven times more than the domesticated animal, which results in seven years. (Talmud, Bechoros 8a)
There is a different version of this story:
A certain philosopher sought to know the gestation period of a snake. He saw some mating, captured them, placed them in a vessel, and fed them. When the elders arrived in Rome, they saw Rabban Gamliel, and asked him, After how long does a snake give birth? He was not able to answer them, and his face fell. Rabbi Yehoshua met him, and asked him why he looked so down. He replied, I was asked one question, and I was not able to answer it. Rabbi Yehoshua asked, What was it? He replied, After how long does a snake give birth? Rabbi Yehoshua said, After seven years. Asked Rabban Gamliel, How do you know? Rabbi Yehoshua replied, The dog is an impure wild animal, and gives birth after fifty days, and an impure domesticated animal gives birth after twelve months; and it says, “You are cursed from all the domestic animals and from all the beasts of the field” – just as a domestic animal is cursed seven times more than a wild animal, so too is the snake cursed seven times more than the domesticated animal. Towards evening, Rabban Gamliel went out and told them. [The philosopher] began to bang his head against a wall, and said, I worked and exerted myself for seven years [to discover this], and this one comes and holds it out on a cane (i.e. answers lightly). (Yalkut Shimoni, Bereishis 3, os 30)
This version is interesting in that it shows how the Sages did expect themselves to be able to derive scientific knowledge from the Torah, yet they were not all able to do so with perfection, as we see with Rabban Gamliel’s distress at not being able to answer the question.
But is it true that a snake's gestation lasts seven years?
It has been confirmed that female snakes sometimes give birth several years after mating. In general, this seems to be due to their ability to store sperm. It has been suggested that in some extreme cases, it resulted from long term “mummification” of embryos instead.[1] In other cases, snakes have been known to reproduce via parthenogenesis, i.e., without a male;[2] some scientists suggest that all cases of isolated females giving birth are due to parthenogenesis rather than storing sperm or embryos from an earlier mating.[3]
Although Rav Yehudah’s statement seems to be an astonishing example of scientific information being extracted from the Torah, there are some difficulties with it. First of all, although in one instance it was recorded that an Arafura File Snake laid eggs exactly seven years after mating,[4] this was in one case alone. The maximum on record is nine years, with a garter snake.[5] The majority of snakes do not store the sperm at all; even in those that do, it is usually for far less than seven years. Furthermore, the statements in the Talmud concerning the gestation periods of other animals are certainly at odds with contemporary knowledge:
The wolf, lion, bear, leopard, bardelas, elephant, monkey, and kifof have a gestation period of three years. (Talmud, Bechoros 8a)
Yet contemporary observations show that the gestation period of, for example, wolves and lions are approximately 62 days and 110 days respectively.
What are we to make of all this? The account in the Yalkut shows that the Sages were not all able to derive whatever biological knowledge they wanted from the Torah. But does it show that any of them could? It does seem to show that they considered themselves able to do so in some cases. It seems that R. Yehudah/ R. Yehoshua derived the knowledge of the snake’s long gestation from the Torah, rather than using the Torah source as an additional proof for something that they knew from experimentation. But can we confirm this claim? On the one hand, there are indeed some cases where individual snakes give birth seven years after mating. On the other hand, this does not appear to be true for any species. There is no type of snake that has a seven-year gestation - instead, individual snakes can give birth for any number of time after mating, from several weeks to nine years or more. Furthermore, some of the other biological information in that section is clearly inaccurate. It is difficult to know what to conclude.
NOTES
[1] R. Shine, P. Harlow, J. S. Keogh, and Boeadi, (1995), ‘Biology and Commercial Utilization of Achrochordid Snakes, with Special Reference to Karung (Achrochordus javanicus),’ Journal of Herpetology, 29 (3): 352-360.
[2] Parthenogenesis has been documented in some lizards, insects, and other species including domestic turkeys.
[3] University of Arizona herpetologist Gordon W. Schuett, in “Snake Birth An Unlikely Feat,” The Detroit News, Monday October 6th 1997.
[4] Magnusson, W. E. (1979), “Production of an embryo by an Achrochordus javanicus isolated for seven years,” Copiea: 744-745.
[5] Robert T. Mason, Department of Zoology, Oregon State University.
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17 comments:
The following question might be tangential to the main thrust of the post, but maybe not, depending on the answer:
"(Rabban Gamliel) was not able to answer them, and his face fell."
Why did his face fall (because he didn't know the answer?, or because he didn't know how to derive the answer from the Torah?), and what can we learn from that?
Well, the obvious answer is that nature has changed, so the taanaim were of course correct when they said these things…
Or perhaps they were referring to a specific species of snake unknown to modern science…
Which brings up another point. This gemara treats all snakes as if they were the same species and should have identical gestation periods.
Or it could be that the taanaim weren’t zoologists…
I wonder if the story with the Roman philosopher actually happened? It seems like too much of a coincidence that he happened to observe a snake have babies seven years after mating (which you pointed out is not typical) and this matched perfectly with what Rabbi Yehoshua figured out.
While I think that Rabbi Levi's piece on this is nice, your points are well taken. But it seems to me that while you may be able to use this in your defense there is another aspect that to my knowledge has not been acknowledged.
It seems to me that your defenders, on this blog and elsewhere, treat it as a devar pashut that Chazal derived their knowledge of science from the non-Jews. This assertion, while I don't presume to argue otherwise, is generally stated categorically. You have in your post noted that at times Chazal derived some of their opinions from their Torah (though not everyone could or felt they could). Furthermore, this Gemara proceeds to record Chazal as claiming to be wiser than the non-Jewish scholars on a matter of biology. While I do not mean to argue that this should trump other Gemara's which may take a different approach, it does seem to me to negate the tendency of some apologists to dismiss the belief that Chazal had expertise in the natural world as without basis in Jewish tradition.
"The Emperor once asked R. Joshua b. Hanania: ‘How long is the period of gestation and birth of a serpent’? — He replied to him: ‘Seven years’. ‘But did not the Sages of the Athenian school couple’ [a male serpent with a female] and they gave birth in three years’? — ‘Those had already been pregnant for four years’. ‘But did they not have sexual contact’? — ‘Serpents have sexual intercourse in the same manner as human beings’.‘But are not [the sages of Athens] wise men [and surely they must have ascertained the true facts about the serpent]’? ‘We are wiser than they’." Bechoros 8b Soncino trans.
wow. this is a great post!
G*3, about whether it happened:
my guess is that the story is fictional and a polemic. this seems like the genre, and the conclusion with knocking his head against the wall while declaring the moral is just too precious.
i put forth this theory here.
if he wanted to make sure that he was getting the gestational age, he should not have kept the male and female confined together. indeed, why keep the male at all? except of course that you cannot see the genitals of a snake from the outside, but one needs to probe or pop. maybe he kept them separately, but was unsure which was female until she gave birth.
i would guess that this story is fictional. besides reading like a polemic, the philosopher and the rabbi arrived at an identical false number. to arrive at the identical true number is plausible, if both are ways at arriving at truth. but arriving at the same false number is mathematically improbable.
if so, there are two possibilities: (1) they had the derasha which gave them false scientific knowledge, and attributed this same position to the philosopher because they believed it to be truth, and so he was duly impressed.
(2) despite the message of being able to derive from pesukim, they took this scientific tidbit from the gentile scientists. (note how the seven years equals the other scientific statement of a spine turning to a snake after seven years.) chazal often will derive knowledge they know from elsewhere from a pasuk. even unto the direction of bavel from eretz yisrael, and that the sun rises in the east! so i would posit that this derasha was built on a known scientific fact, but then in the polemic, the derasha was made primary.
i would favor the latter explanation.
kt,
josh
Very interesting subject and article: analytical, yet respectful towards Chazal(no "tone" issues in my opinion!).
(I am wondering if R. Slifkin can post in the future on a related concept to Chazal divining nature from the Torah; ie, Chazal *controlling* nature; eg, Yerushalmi of Beis Din adding an extra month, causing a three-year old girl to become a besulah again; IIRC, it's quoted in one of the Poskim as well.)
I'm not sure if i should be grossed out or amazed at the picture. :-)
This blog is fantastic. keep it up
With regards to Chazal 'controlling' nature, here is an interesting quote from an article (which you may not want to publish as it comes from a source which is fairly antagonistic to Torah):
"Moreover, Chazal even thought -- and the most of later rabbis adopted their view -- that they could determine factual reality by issuing Halachic rulings. Thus they thought that if a girl under three years old had sex with a man her hymen would eventually regenerate. By "three years" they meant neither solar not lunar years, but three calendar years, the length of which can vary up to a month, and which were determined by the Sages themselves. Not only were Chazal aware of this fact, they even stated explicitly: "A girl three years old and a day, if the Beit Din determined that year as a leap year -- her hymen regenerates, and if not -- it does not regenerate" (The Jerusalem Talmud, Sanhedrin 1:2). If a girl became three years old and had sex with a man and then the Beit Din determined that year as leap, so that "according to the calendar" it would take her another month to turn three, her hymen would regenerate, and if the year was not determined as leap, her hymen would not regenerate! Thus the Sages' Halachic rulings determine biological processes in the body of a girl who may even not be aware of the Sages' existence.
Bizarre as it is, this view was adopted almost unanimously by the Achronim. The author of Pnei Moshe, the most accepted commentary on the Jerusalem Talmud, wrote on this issue:
"G-d agrees with the earthly Beit Din, so that if she is three years and a day old, if she has intercourse, her hymen does not return; but if the Beit Din changed their mind and ruled that year or month to be intercalated, as said above -- her hymen returns if she has intercourse, for she had not yet become three years and one day old. So the Writings teach us that even nature agrees with them [the Sages], according to His decree, glorified be He."
And the Chazon Ish wrote in his commentary on Orach Chayim (39:15) that, in fact, whether or not a girl's hymen would regenerate depends on the decision of the Beit Din.
I am at a loss as to how to respond to errors on matters of fact and methodological misconceptions of this magnitude. Can you help me?"
Although I would have phrased the question more respectfully, it is still a valid question, and the difficulty is that here it is not so easy to use the approach that 'Chazal relied on the faulty science of their times', since Chazal here are explicitly deriving a rule regarding physical reality. It would be interesting to see if and how the Rambam codifies this.
The 800 pound elephant in the room that nobody wants to talk about is the many pesukim in nach that without creative explanations clearly contradict current knowledge in science and nature. Until this is properly addressed the cannot be any truthful dialog. Are we to say that everything is nach is infact perfectly in tune with science, while accepting that this is not the case for hazal a mere 350 years later?
Steve, elephants don't weigh 800 pounds. I think you mean "400 pound gorilla."
I certainly discuss scientific problems in Tenach. Just not in this post. Let's keep the discussion focused.
To Joseph,
Rabbi Akiva Tatz has some fascinating online talks that discuss this topic. He gives examples that make the point that
nature is a mask, and that people on a certain level are basically beyond nature. For more detail than I can give here, you can listen at http://www.simpletoremember.com/authors/a/rabbi-akiva-tatz/
A couple of talks that deal with this issue are: World Mask- Torah- The Cause of Reality, and World Mask- Nature and Miracles: the 4 levels.
Rabbi Tatz's approach does not represent the rationalist worldview. The goal of this website is to explore the rationalist worldview.
How about as a foil, like several other posts at your blog do?
To Rabbi Slifkin,
You are certainly correct in that Rabbi Tatz does not reflect the rationalist worldview; that is one of the reasons that I didn't elaborate in my post (along with constraints of time and space). I do think that it is worth noting, however, as one possible way of approaching the issue, even if it's not one that would be pursued in this forum.
Have a Shabbat Shalom
> Steve said... The 800 pound elephant in the room that nobody wants to talk about is the many pesukim in nach that without creative explanations clearly contradict current knowledge in science and nature. Until this is properly addressed the cannot be any truthful dialog. Are we to say that everything is nach is infact perfectly in tune with science, while accepting that this is not the case for hazal a mere 350 years later?
This is off-topic, but I think this is why the mainstream frum community reacts so strongly against a rationalist point of view. If everything in the Torah is mystical and metaphysical inconsistencies with what we observe can be hand waved as things we don’t understand; as mystical concepts outside the physical realm; or in the extreme cases as explicitly denying that there is such a thing as natural laws.
Once we try to reconcile Torah with the world we observe we run into all sorts of problems, and it is a very short step from saying Chazal were wrong in places to saying Tanach was wrong in places to dismissing the entire thing as iron-age mythology.
I think the simple meaning of the yerushalmi is not metaphysical. Rather, that halachically, three years are necessary, and this follows chazal's setting of 3 years. So if it's an ibur shana, it takes place after an additional month. According to this, the gemara is describing a legal-halachic reality, not a physical-metaphysical one.
G*3--
"Once we try to reconcile Torah with the world we observe we run into all sorts of problems, and it is a very short step from saying Chazal were wrong in places to saying Tanach was wrong in places to dismissing the entire thing as iron-age mythology."
If it's wrong, it's wrong, and you have to deal with it, not poke your head into the sand. And why is "the obvious answer" that "nature has changed?" It's not obvious to me. What possible scientific basis could you have for suggesting that wolves ever had a 3 year gestation period?
i thought that snakes laid eggs not give birth? im so confusedd so snakes can give like natural birth? but their not mammals or anything..please someone help me figure this out..
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