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I have heard claims that experts in the world of Torah were significantly ahead of their counterparts in the world of natural science (or mathematics, or psychology, or…) in that they knew X (some fact) centuries before the scientists/whatever did. I've never seen evidence of any of these claims. Is there any such true claim?

To be precise: Is there any scientific/similar fact (or fiction) which is now accepted by the establishment but which was claimed by rabbis generally or by some famous rabbi before it was accepted by the (non-Jewish) establishment?

(Answers with good evidence only, of course.)

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One problem you may have in getting an answer is that once the Rabbis demonstrated such knowledge it became part of the accepted knowledge, and we think of the secular world as knowing that. History is not precise enough to tell us that the Rabbis were the ones who originated this knowledge. –  Ariel Dec 18 '12 at 10:03
I heard a really good one about the number of known stars in the universe being mentioned by the Gemara. And I heard it from a NASA scientist who was telling me how impressed he was! I have to ask him again to tell me the details... –  Seth J Dec 18 '12 at 15:42
I emailed this question to R' Natan Slifkin, and he responded that he's looked into this extensively and never found an example that holds water. –  Isaac Moses Dec 20 '12 at 4:45
@LazerA, that should be a fine book for those interested in the subject. I would argue it's sufficient to show that Chazal consistently held views that corresponded with the best science available at their time. That itself would indicate they were ahead of their time. You'll find that some of the best scientists of any era, had/have a tendency to engage in pseudoscience and superstition outside their own field. Today, there are countless doctors, supposedly educated in science, who believe in and promote crackpot medicine. –  Ephraim Feb 9 at 9:43

16 Answers 16

Ralbag (Gersonidies) has the earliest known use of a proof by mathematical induction in his mathematical work Maase Hoshev (1321 CE).

Source: Rabinovich, N. L. (1970). Rabbi Levi Ben Gershon and the Origins of Mathematical Induction. Archive for History of Exact Sciences, 6(3), 237-248. Available in JSTOR here.

(For comparison, the prevalent thought before the above article was written was that mathematical induction was first used explicitly by Pascal ~1665 CE.)

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+1, thanks much. –  msh210 Dec 18 '12 at 15:31
This brings up the question: Does this count as other than "the world of natural science"? In other words, when he wrote about math, was the Ralbag building/drawing on a tradition from Torah sources, or one from secular sources? –  Isaac Moses Dec 18 '12 at 17:13
However true this may be, induction is not a fact, as asked in the original question. It is a mathematical method. –  rbp 2 days ago
@rbp The fact that it's not fallacious? –  Double AA 2 days ago

I would say the biggest explanation ahead of its time was not by the rabbis, but by the Torah, steadfastly defended by even the most rational rabbis in the face of prevailing secular thought. Up until 1929 (and perhaps even as late as 1949), the leading view in astronomy was that we lived in a steady-state universe with no beginning and no end. People often talk about the clash between Big Bang theory and ma'asei bereshit, but in fact they are much more in line with each other than the prevailing secular theories up until that point.

For those numerologists out there, Tehillim 147:4 "He counts the number of the stars; He calls them all by name. ד. מוֹנֶה מִסְפָּר לַכּוֹכָבִים לְכֻלָּם שֵׁמוֹת יִקְרָא:" With 22 letters in the Hebrew alphabet, there are 22! = 1.1x10^21 possible permutations, pretty close to the number of stars in the observable universe (if shin and sin are counted separately, as they should be, you get 23! = 2.6x10^22, even closer to the "correct" number) [as an interesting aside, this is remarkably close to the number of grains of sand on the beach: 5x10^21 according to some estimates]

And for my favorite, which doesn't really count as preceding modern science, but is cool anyways, Tehillim 148:3 "Praise Him, sun and moon; praise Him, all stars of light. ג. הַלְלוּהוּ שֶׁמֶשׁ וְיָרֵחַ הַלְלוּהוּ כָּל כּוֹכְבֵי אוֹר:" Isn't "stars of light" redundant?? NO! there must also be stars of darkness, i.e., black holes!

I'm not really a big kabbalist, but from what I understand of the sefirot, it is conceptually very similar to our modern particle physics theories of symmetry breaking.

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I don't see why there are 22! permutations of letters. Can't letters be repeated or unused in a name? In any event, the part of this that answers the question is the first paragraph AFAICT. –  msh210 Dec 18 '12 at 19:14
@msh210 and it does seem the biggest explanation ahead of time. Except that everybody knew it when Adam was created... Doesn't that also count as a scientific fact (back then)? :) –  yair Dec 19 '12 at 1:01
@msh210: like I said, it's a bit of numerology. I guess you have to think of some unique naming system, so permutations of the alphabet seems as good as any. –  Jeremy Dec 19 '12 at 13:57
Why would black holes be exempt from praising HaShem? –  Seth J Mar 14 '13 at 17:39
@SethJ: they'd be included in the more generic כל צבאיו of the previous verse. –  Alex Jun 25 '13 at 16:05

Torah Shleimah (BeReishis 1:1 note 30) quotes the Rama in Toras HaOlah who says that Chazal (Yerushalmi Avodah Zarah 3:1, BaMidbar Rabbah 13, Zohar VaYikra 10, Zohar Chadash 15) knew the earth was round before the non-Jews (he gives the date that they knew as 5252, i.e. 1492, whereas Wikipedia claims that it was already known by that time that the world was round).

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en.wikipedia.org/wiki/Round_world It seems the Greeks had figured it out long before, even if many Medieval Europeans were unaware. –  Double AA Dec 18 '12 at 6:12
The Zohar (not sure where in the Zohar) says the world was round. –  Hacham Gabriel Dec 18 '12 at 14:41
@HachamGabriel This answer says it's in Zohar VaYikra 10 and Zohar Chadash 15, but even the Zohar was written after the Greeks had figured it out. –  Double AA Dec 18 '12 at 14:55
@DoubleAA maybe it's one of the things the was passed down from Har Sinai. –  Hacham Gabriel Dec 18 '12 at 15:02
@HachamGabriel Sure but anything could be. Just speculating that is a pretty weak answer. (If you had a source on the other hand...) –  Double AA Dec 18 '12 at 15:04

Rabbi Y.L. Rapaport suggested that R' Yehoshua Ben Chananiah's statement

(כוכב אחד לשבעים שנה עולה ומתעה את (הספינות

(בבלי מסכת הוריות דף י עמוד א)

refers to the periodicity of Halley's comet, about 1500 years before Halley discovered this.

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Suggested by whom? –  msh210 Jun 23 '13 at 16:58
@msh210 Rabbi Yehoshua Ben Chananiah –  Argon Jun 23 '13 at 17:20
He suggested that his statement refers to Halley's comet? Can you cite where he did so? –  msh210 Jun 23 '13 at 19:27
@msh210 He did not say he was referring to "Halley's comet" explicitly (what would he even call it?). However, this "star" that occurs every "seventy years" is generally assumed to be referring to Halley's comet, as it recurs every 75-76 years. See e.g. books.google.com/… –  Argon Jun 23 '13 at 20:18
This is another ridiculous claim. The Talmudic term for comet is כוכבא דשביט - see ברכות נח. It's improbable that a comet, which is distinct from navigational stars would confuse sailors. We NOW know that Halley's comet returns every 76 years and could not possibly been seen at time of the cited story. (It should be noted that when it was conjectured that this gemara refers to Halley's comet, the exact period of the comet was not known. Some scientist believed that the period was degrading and slowing down. Hence, it was believed that centuries earlier, the comet returned every 70 years.) –  Ephraim Feb 9 at 9:01

One example I have heard is the amount of stars in the universe (from here):

In case you're concerned that the rabbis of the Talmud really hadn't a handle on what's going on in the skies, here's something to make you think again: The current estimate of the number of stars in the universe is about a thousand billion trillion (10^24). The Talmud (Brachos 32b) states as follows:

Each of the Zodiac constellations has 30 armies. Each army has 30 legions. Each legion has 30 divisions. Each division has 30 cohorts. Each cohort has 30 camps, and each camp has 365,000 myriads of stars.

Doing the math: 12 x 30 x 30 x 30 x 30 x30 x 365,000 x 10,000 = 1.06434 x 1018

But then we have to include the other non-Zodiac constellations, bringing us closer to the 24th power. Apparently, these rabbis had a higher source of knowledge.

Rabbi Zamir Cohen published a book called "The Coming Revolution", bringing many examples of how "Science discovers the Truths of the Bible". This audio shiur, "Nothing New Under the Sun - Science in Torah" attempts to collect several more such examples.

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Sorry to disappoint, but your math is wrong. It's not 106,434 x 10^18, it's 1.06434 x 10^18, which is not equal to 1^22. To make it worse, 10^18 is 0.0001% of the correct value. Including non-Zodiac constellations doesn't help at all. (How do you define non vs Zodiac constellation anyway? A region in the sky? The specific stars (or galaxies) that make up the constellation shape?) –  Ariel Dec 18 '12 at 9:51
I understand your point - that fact that they knew that there were incredible numbers of stars at a time when only 6,000 or so were visible is certainly significant. Another error in the math I just noticed: It's says 365 myriads, yet they are multiplying 365,000 myriads. BTW I contacted the author and asked him to fix his math. –  Ariel Dec 18 '12 at 12:45
@Ariel: The Talmud (Berachot 32B) says 365 thousands of myriads. - halakhah.com/berakoth/berakoth_32.html –  Menachem Dec 18 '12 at 17:01
I contacted the author and he wrote back: "Just looked at my source, "A Glimpse of Light" by Dr. J. Schamroth. He includes a corrigenda--and that's one of his corrections!" The math was corrected on the chabad.org site, so I'm going to correct it here as well. –  Ariel Dec 18 '12 at 22:00
I would be very cautious (or rather selective) when citing Zamir Cohen. A lot of the material in his books is absolute nonsense, superstitious pseudoscience and has nothing to do with Torah. (And thus, raises the issue of דרכי האמורי). –  Ephraim Feb 9 at 8:53

Nahmanides, (1194-1270), on Exodus 13:16 says on the phrase about the head phylacteries 'as a reminder between our eyes', In verse 9,

... That we should place them in the place of memory between the eyes, that is the beginning of the brain (the prefrontal cortex allows for executive function, which facilitates cognition) and it is the beginning of memory and maintaining forms after they are removed from before one (short term memory is stored in the frontal lobe)... And the knot in the back of the brain guards the memory* (long term memory is stored in the hippocampus, which is in the medial temporal lobe)...

So Nahmanides described impressively accurate locations for the short term memory centers of the brain and the cognitive center, and had a pretty accurate idea of where long term memory is stored long before it was scientifically established.

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Does anyone know where he got this idea from? –  Double AA Feb 16 at 18:21
@DoubleAA edited, I agree that by today's standards that isn't pinpointing. I don't know where he got it from, but from the article about the history of neuroscience it really doesn't look likeitcame from his contemporaries, as structural analysis of the brain didn't really start even in broad strokes until the 16th century. –  Baby Seal Feb 16 at 18:28
You wont find it in neuroscience, but the intuition that the deeper into the head you go the longer term the memory could definitively have been floating around. –  Double AA Feb 16 at 18:38
@DoubleAA I edited "before everyone" to "before it was scientifically established". It seems from that article that people had really only established that the brain plays a part in intellect by Nahmanides' time. I guess you'd have to do more exhaustive research than likely either of us have time for to be sure. –  Baby Seal Feb 16 at 23:05

The Ramban, in his commentary on Bereishit, writes that there were only two actual "creations" and the rest were more of "formations". He says that the two things that were actually "created" were light (and the resulting difference between that and darkness) and a "small point that had no substance" (נקודה קטנה שאין בה ממש). This seems to be a reference to the Big Bang, in which there was a large amount of positive energy that was in a very small "point".

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+1, but more information would be appreciated. –  Shmuel Apr 17 at 22:11
if i remember correctly on that Ramban he says that his point became something that "has substance". Energy into matter, perhaps... –  bondonk May 13 at 4:20

The Baal HaTanya writes:

והיינו הגוף שלהם גדול כ"כ שהוא בבחי' מקום ומאחר שהם בבחי' מקום הרי הם ג"כ בבחי' זמן שהמקום והזמן שניהם הם נבראים בבחי' א

So in other words, time cannot exist without space, and space cannot exist without time, they are one type of creation.

Although I'm not sure the exact date of this Maamar, given the style it would seem to be somewhere between 1798 and 1813.

At that time Newtonian physics was what was popular, and in it (according to Wikipedia) space and time are not interconnected at all. This view was abandoned with special relativity around 1905.

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Space and time still had been grouped together before special relativity, eg. as forms of basic intuition in The Critique of Pure Reason. –  Double AA May 12 at 20:42
@DoubleAA, I don't know what you mean by "grouped together". You mean that he suggests that one cannot exist without the other, and that lacking one would mean the other isn't there was well? Is that the earliest date you have for that concept? –  Yishai May 12 at 20:45
It means that they have certain properties in common and certain different (as in all analogies). Frankly I don't know what בחינה א' means either. Does it mean that they are both part of a 4D manifold? Is that what בחינה means? –  Double AA May 12 at 20:47
@DoubleAA, of course it can mean different things depending on context. But the context here is that one cannot exist without the other, and that if one doesn't exist, by definition the other doesn't as well, so the creation of one is the creation of the other. –  Yishai May 12 at 20:51
Does science agree to that, though? Could the world have been created with 6 time dimensions and 2 space dimensions? Or 4 space dimensions and 0 time dimensions? I don't know that science has an opinion on that. Special relativity AFAIK doesn't. –  Double AA May 12 at 20:54

I saw a presentation which gave 2 specifics (though I'm no scientist and had to take the presenter's word for it):

that the gemara posits a 10 dimensional universe (or some number like that) and science is now coming around to a similar view [I found this which seems to be related]

that the gemara puts an embryo turning into a fetus (first heartbeat) at 40 days and science eventually comes up with 42 days or some such.

but again, I'm a liberal arts guy so take with as many grains of salt as you wish.

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is there any proof that either of those were "ahead of their time" or just reflecting things around them? –  Charles Koppelman Dec 18 '12 at 22:11
are you asking if, in the time of the gemara, there was medical knowledge that the first heartbeat is at 40 or so days? or is contemporaneous with the kabbalah there was a scientific opinion that we live in a 10 dimensional universe? –  Danno Dec 18 '12 at 22:43
I was asking about the heartbeat, but it applies to both. –  Charles Koppelman Dec 18 '12 at 23:26
medieval theologians believed (in other religions as well, though I have seen people trace the christian notion to the talmudic source material) that the soul was infused at 40 days. I don't know of medieval medicine which tied that to a first heartbeat which has been, with the advent of ultrasound, measured at between 36-40 days. –  Danno Dec 18 '12 at 23:44
Why medieval? The gemara was written long before medieval Europe (whose science, incidentally, was much less sophisticated than the time when the gemara was written). In order to answer if the gemara's science was ahead of its time, we'd have to compare it with contemporary sources - Babylonian and Roman science from around the 5th century. –  Charles Koppelman Dec 19 '12 at 20:37

If we're counting mathematical comments by rishonim (Medieval Scholars), then in addition to @DoubleAA's reference to Ralbag (Gersonidies) who has the earliest known use of mathematical induction, other Jews have made some strides here as well.

R. Avraham bar Chiyya has an interesting proof that the area of a circle is equal to half its radius times circumference. This is also shown in Tosfos to Sukka 8a, who I presume got it from Avraham bar Chiyya.

In addition, while this is no scholarly source, there's a magazine article discussing how Maimonides/Rambam was the first to state that pi is an irrational number. However, seeing as the Rambam doesn't prove this, it seems like he was just saying that his own instruments weren't able to measure pi precisely.

Of course, cases like these merely show that these Jews were involved in science and mathematics, and may have made discoveries in those fields.

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Was R Avraham bar Chiyya the first to prove that? –  Double AA May 12 at 21:15
@DoubleAA Yes, and though his mechanical proof isn't considered to be a 'proof' by today's standards, it has been proven mathematically by Israeli mathematicians. I'll find try to find the article later –  Matt May 12 at 21:25

Many people, specifically Breslov chasidim put a huge emphasis on being happy. Nowadays scientists are beginning to say that being happy mentally actually effects the body physically in a positive way.

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Did those people (such as the Breslov chasidim) claim that being happy was a good physical thing to do, or spiritual thing to do? –  Double AA Feb 21 '13 at 5:36
Both. Though probably more so spiritually. The point still stands that they recognized it was the "right" way to live, and now science is justifying that. –  andrewmh20 Feb 21 '13 at 5:39
@DoubleAA Reb Noson zy'a says (I think in Likutey Halachos but maybe elsewhere) that a person who is happy will not experience suffering physically from any ailments they might have. Now that I think of it it's probably Yimei Moharnat, in the context of his intestinal illness. –  yoel Feb 21 '13 at 5:45
מצוות לאו ליהנות ניתנו –  b a Feb 21 '13 at 6:26
What do you mean? –  andrewmh20 Feb 21 '13 at 12:27

Chazal understand HaShem's name Shakai to mean "She-amer dai" - that the universe expanded until HaShem said enough. (http://www.jewfaq.org/name.htm)

According to prevailing scientific theory, there was an inflationary epoch, wherein the universe expanded much faster than the speed of light until "between 10−33 and 10−32 seconds after the Big Bang", when it slowed dramatically.

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So the world was big enough 10<sup>-32</sup> seconds after it was created? (BTW, I didn't downvote, just trying to understand your answer). –  Yishai May 12 at 20:49
@Yishai Perhaps larger than 10^{10^{10^{122}}} megaparsecs. A megaparsec in 3 billion billion kilometers. –  Ypnypn May 12 at 20:52

Nidah 51b states: “All fish that have scales also have fins and are kosher, but there are fish that have fins but do not have scales and are unkosher".

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You're missing half of your answer: does the "scientific establishment" agree to this statement? –  Double AA Dec 19 '12 at 14:18
Also, do you know that Chazal were the first to claim this? –  Double AA Dec 19 '12 at 14:26
I highly doubt that Chazal were the first people to realize what kinds of fish exist. –  Shmuel Apr 17 at 22:09


An accepted scientific theory is that the universe was created ex nihilio.

a)This article illustrates a Jewish precursor to the Greek ideology with whom this theory is mostly attributed to. http://www.hashkafacircle.com/journal/R2_RS_exni.pdf


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-1 Article (b) has many issues, and is certainly not an "accepted scientific theory." The Big Bang, btw, is not "ex nihilo." –  Shmuel Apr 17 at 22:14

Rabbi Yonason Eibshitz(born 1690) in his sefer Tiferes Yonason on the Torah he writes in parshas Noach that during the for haflaga there were people who were trying to flee and land on the moon and live there.He describes a flying ship with masts some like to say he was referring to a spaceship.From the way he details the ship it is not like our spaceships per se but definitely an advanced craft to think of and mechanics it works with.

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Read it inside here hebrewbooks.org/pdfpager.aspx?req=19492&st=&pgnum=17 –  sam Jul 11 '13 at 1:00
Rav Eybeschutz was not the first person to speculate on traveling to the moon. See McDermot's "Trip to The Moon", 1728. There are other examples dating back to the mid-17th century. RYE's vision was not unique. –  Ephraim Feb 9 at 10:11
Do they describe how to get there? –  sam Feb 9 at 18:38

This is a social rather than a scientific example, but it's interesting nonetheless. Marital rape is absolutely forbidden by Chazal and strongly condemned by rishonim as well.

See some sources here:


In contrast, marital rape was not illegal in Western countries until the 20th century, and is still legal in numerous non-Western countries.

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The question specifically asks for scientific examples. How is this relevant? –  Charles Koppelman Jun 24 '13 at 17:13
It's an example of something about which the rabbis were ahead of their time. They knew marital rape was wrong 2000 years before anyone else. The poster's request was quite broad "scientific/similar fact (or fiction)." I suppose you could say it's a moral fact that rape is harmful and wrong even if it occurs among spouses. –  Kordovero Jun 25 '13 at 1:44

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