Overview: There’s a common misconception that turns the rabbis into supermen who can never make a mistake in science or Halacha. This chapter will bring sources and proofs that demonstrate the possibility for error in rabbinic work, including some science in the Talmud.
Naturally, one of the most common questions on the Oral Law is how we know it was properly preserved and accurately transmitted. Can there be mistakes in the tradition? Are the rabbis considered infallible?
Although it might come as a shock to some Orthodox Jews, truthfully speaking there’s no Torah-basis to the assumption that rabbis are supermen who can’t make mistakes in their teachings. In fact, all logic goes against that and there are Torah-sources that prove how mistakes are indeed possible—and happened.
Yet despite this fact, we are bound to the rabbinic authority as a matter of principle. This is like the absolute power of government courts despite the fact no one is denying they are fallible humans who may err. We may have a hard time distinguishing and identifying what those mistakes are, but we still recognize the possibility of errors within the vast bulk of rabbinic literature.
We obviously cannot pick and choose what we believe is a mistake and what is not, for doing so would defeat the whole purpose of their authority. This is true not only in action—that we must practice what the rabbis instruct us, but also in thought and belief. It would make sense to have some faith in the rabbis. After all, chances are these sages were much sharper and cleverer than you and I. Just like we usually put our faith in scientists because we trust their professional conclusions, no less should it be with our trust in the sages. This is all the more so in light of the special divine assistance (known as seyata deshmaya or ruach hakodesh) the sages get from the One who trusted and appointed them to their sacred task.
The Torah writes of the Supreme Court that “you shall not turn from their words right or left.”[i] This implies that even when there’s a chance of them erroring, it’s still G-d’s will that we keep their rulings. It’s our responsibility to listen to all their rulings while it’s theirs to avoid mistakes as much as possible.
Sefer HaChinuch mitzvah 496 says:
“‘You shall not stray from [it] right or left’—even if they say to you about right that it is left, do not stray from their commandments”—meaning to say that even if they err in one of the things, it is not fitting for us to differ with them. Rather, we should do like their mistake. And it is better to suffer one mistake, and everything be given over under their constant good opinion; and not that each and every one go according to his [own] opinion. As with [the latter], there would be destruction of the religion, dissent in the heart of the people and total loss of the nation.”
Well, you might now be wondering; isn’t the Oral Law concept similar to the ‘broken telephone’ game where many mistakes are expected, if not inevitable?
There are a few big differences between the broken telephone game and the oral fashion of transmission.
As mentioned earlier, only a considerably small number of details about certain Mitzvos originate from Sinai. The clear majority are rabbinic inventions. It’s not clear whether it was permitted to write those “rabbinic oral laws.” If it was allowed, then this issue is trivial since the broken-telephone game would only be with a small amount of information, i.e. the oral laws stemming from Sinai. But even in regard to the “Sinaic oral laws,” the transmission process was far different than the game of broken telephone.
For starters, these were the biggest geniuses of the generation with memories one of a kind. Second, they were the most G-d-fearing men, who would put the greatest concern not to forget or err. Thirdly, it’s not a one-time study-and-go, but years of repetition, learning the same material over and over. Fourth, even if one were to get mistaken, he would immediately be corrected by his companions in study. Fifth, while it was prohibited to put this Oral Law in public writing, having personal private “notes” (known in Talmudic terms as megillas nistarim) to review the material was permitted.[ii]
Back to our previous discussion, here are some Torah-sources that confirm this possibility of rabbinic error:
The High Court is required to bring a sacrifice when unintentionally diverting a law that includes all of Israel.[iii] We find arguments as well in factual reality (e.g., the argument between Shmuel and Rav Ada regarding the exact length of the solar year[iv]). Obviously one of these rabbis had to be mistaken because they each contradict the other. Similarly, there are arguments regarding some versions of many texts in the Talmud, as well as different explanations for it. Obviously, the Talmud had only one explanation, leaving only one commentator with the truth. See Rosh Hashanah 25a regarding the possibility for the High Court to make a mistake in the calendar calculations.
See Pesachim 94a which states “and it was the rabbis who were mistaken.”
Often, the Talmud and other Jewish works mentioned the science of its times,[v] either the science of the world in general, or the science of the Jewish thinkers themselves. Some of the science has been outdated since. In light of the above, this of course presents no problem to the rabbis, who are actually human and thus fallible. Much of this science can be found in tractate Pesachim page 94 and the remedies found in Gittin 67b and further.   For more discussion on this topic, see chapter “Did the Wild Stories of Midrash Actually Happen?”
This, however, is only regarding part of the Oral Law; most of it, though, was preserved in an elegant transmission process from generation to generation. The sages are known to have put great concern and emphasis on both academia and religion, which would minimize many potential errors.
 Even according to the opinions in Kabbalah that every word mentioned in the Talmud—including every opinion—was given to Moses at Sinai, that would only be on the spiritual level. On the literal, physical, earthly level there were opinions in the Talmud that were completely wrong. It is possible that the very fact that the sages said their Torah teachings, whether they were mistaken or not, creates a spiritual reality in the upper realms where that Torah statement now remains true in that upper world.
The same applies to Kabbalistic statements like “there are seventy faces [i.e. viewpoints] to the Torah.” Similarly goes with the statement “eilu va’eilu divrei elokim chayim” (Eruvin 13b). On a simpler level of understanding, we can explain these statements to be going on most arguments in the Talmud—and possibly only in Halacha and not Aggadah. Most arguments in the Talmud are based on two logical approaches that don’t disagree about any facts. They are two logical approaches of how to apply the law and how to use the derivation tools given by G-d at Sinai. Logic itself often allows for opposite approaches to both make sense. Because they are both valid, being that they are both logical and coincide with the derivation tools, they are both valid in G-d’s eyes because that is exactly what he wants—the sages to use their logic to apply law. In practice, however, although they are both “true” in this sense, only one approach can be practiced in action. Because unlike logic, action doesn’t allow for opposites to both be true simultaneously.
 Of course, we shouldn’t run to such a conclusion when not understanding a statement properly. The sages were clearly very smart people and wouldn’t be mistaken on basic scientific ideas. But when it comes to science that is hard to test, such as in cases where sophisticated modern equipment is needed, we can understand how the sages could be err. A good example would be concerning the shape of the Earth. Back in primitive times, many or perhaps most people believed that the Earth was flat. Some believed it was round, but the bottom half was engulfed in water, and some believed that it was round, as science today knows. We cannot blame anyone who thought the Earth was flat. After all, everywhere we look, the Earth still seems flat. There weren’t any rocket-ships or satellites to show a round, sphere-shaped Earth. So some rabbinic sages embraced that popular position, unsurprisingly.
R”I of Barcelona (in his book Sefer Yetzirah p. 254a) says in the name of Rav Saadyah Gaon that indeed a minority of sages took the position of a flat earth. The Talmud in Pesachim 94b states: “The Jewish Sages say that during the day the sun travels beneath the firmament and is therefore visible, and at night it travels above the firmament. And the sages of the nations of the world say that during the day the sun travels beneath the firmament, and at night it travels beneath the earth and around to the other side of the world. Rabbi Yehuda HaNasi said: And the statement of the sages of the nations of the world appears to be more accurate than our statement. A proof to this is that during the day, springs that originate deep in the ground are cold, and during the night they are hot compared to the air temperature, which supports the theory that these springs are warmed by the sun as it travels beneath the earth.”
This statement is said in a Halachic context (albeit it itself has no Halachic implications) and is therefore highly unlikely to be metaphoric (as are some other Talmudic statements—see chapter “Did the Wild Stories of Midrash Actually Happen?”). Additionally, it would seem highly unlikely that this “metaphoric” statement “so happened” to parallel a common belief at the time. It’s clear that the Jewish sages, of one generation or another, believed in a flat Earth, as there is no other sober understanding of the above statement of theirs. It would seem as well that Rabbi Yehudah HaNassi believed in a round Earth whose bottom half is covered in water (through and through with no internal mantels to the earth), or that the earth is flat with the water not having a floor-bed at least in some areas.
Similarly, it would seem that Rabbi Nosson, both in his statement on 94a and his statement on 94b (neither quoted here), also believed in a flat Earth. See Bereishis Rabbah 6:8 where this argument between the Jewish sages and the gentile sages is brought as an argument between the Jewish sages themselves (R’ Yehudah bar Illaii and the sages, with an uncertainty who holds what; Rabbi Yochanan says there’s a proof for each position and Rabbi Shimon bar Yochai says that he cannot determine which side is correct).
On the other hand, there are sages who seem to hold to a round Earth. Talmud Yerushalmi Avodah Zara 3:1 says: “R’ Yonah said: When Alexander the Macedonian wanted to go back, he flew [on the back of an eagle] higher and higher until he saw the earth as a ball and the sea as a plate.” While it is uncertain what he meant in the later part of his statement regarding the sea, he does seem to hold to a round Earth. This legend is a Greek one found in other sources besides the Talmud and it seems that R’ Yonah believed in this widespread legend.
Similarly, we find in Bereishis Rabbah 63:14 that the world is compared to a lentil which is round. While this might have been a description of a round flat surface, the comparison to a lentil would suggest that it has a spherical shape.
Another example of an obvious scientific mistake to the modern man can be found in Tamid 32:1. In that narrative, Alexander the Great asks the Rabbis which distance is greater, the sun from the east to the west or the sun from the height of the sky to the earth. The first opinion of the Rabbis held that the distance of from east to west is greater. They proved this with a simple observation. The human eye has an easy time staring at the sun when it is either rising or setting. This, they explained, was because the sun is farther. On the other hand, at midday when the sun is directly above us it is impossible to stare at the sun. This, they explained, is because the sun is closer to the Earth. This is an obvious misunderstanding of modern science which can prove that the sun circles the earth with a perfect circle on a daily basis. The reason that we can stare at the sun when it is rising and setting is because its intensity is obstructed by a greater amount of the ozone layer given the diagonal angle the rays are shining through.
For a larger discussion about the reliability of Aggadah, see https://judaism.stackexchange.com/questions/53349/is-belief-in-midrashim-optional/53351#53351 where many sources are brought to demonstrate the potential fallibility in Aggadah. However, this is all not to say that we should disregard Aggadah. On the contrary, it is a part of Torah and is therefore to be relied upon, with the realization, however, that it may be wrong or the personal opinion of a particular sage.
 Many rabbis explain that the remedies found throughout the Talmud are no longer applicable as our bodies have evolved and changed throughout the years, in effect changing the remedies needed. The Chabad Rebbe (in his work Likkuti Sichos book 23, the third discourse on Shavuos) explains this idea on a spiritual Kabbalistic level; that in essence these remedies are still true today but only in their spiritual sense. He explains that everything from the spiritual worlds transcends into the physical world. This is a fundamental concept in Kabbalah, but a discussion diverting from our topic. However, he continues, whenever the world lowers into a spiritually low state, then the reality of the spiritual truths don’t manifest into the physical reality. This is what happened to the remedies of the Talmud of which are still true in their spiritual roots. See that discourse for a more detailed and comprehensible explanation of what the Rebbe says.
I’d like to humbly suggest that this explanation of the Rebbe applies to some remedies in those days as well. Meaning to say that some remedies didn’t even work back in the Talmudic times but were merely the primitive contemporary sciences of the time from which the Talmudic sages extracted their medicinal advice (see Avraham ben HaRambam in his book Maamar Al Drashos Chazal who says that they were taking the science of the time and were thus mistaken). Hence, back then they were true only in their spiritual roots but weren’t manifested into physical reality (see two footnotes back) and certainly remain so now. But the Rebbe only speaks directly of those that did indeed work in those times but have changed due to the human and environmental changes. As for the reason the Rebbe seems to avoid my suggestion here (and only deals with the remedies that did indeed work at Talmudic times), it is likely due to the general approach of Chassiddus and contemporary orthodox Jewish works which tend to avoid discussing this possibility of mistakes in the Oral Law (although they won’t deny it), largely because it is not something to advertise to the large crowd of innocent believers.
[i] Deuteronomy 17:11.
[ii] Talmud Sabbas 6b, see Hakdamah of Rambam to his Yad Hachazakah.
[iii] Numbers 15:24.
[iv] Talmud Eiruvin 56a, Pirki DeRabbi Eliezer ch. 6, Beraisa DeMazolos ch. 8, Rambam Hilchos Kidush Hachodesh 9:1.
[v] See Niddah 22b, Hilchos Yesodei Hatorah 3:5, Kiddush Hachodesh 17:24, and Igros Kodesh (Lubavitcher Rebbe) 1:1.