During a discussion on Areivim a poster reminded me of a Gemarah I had come across. Chazal believed that the sex of a baby was determined by whether the man or the woman is Mazria first.
I remember that Gemarah quite well. It is yet another instance, one of many I’ve come across that leads me to conclude that Chazal could have been easily, through no fault of their own, mistaken in matters of science. They were limited by the extent of scientific knowledge of their day. Of course as practitioners of the most correct form of Judaism they were quite knowledgeable in matters of Mada. At least as much as their secular counterparts were.
Apparently this was the best knowledge of that era about how the human reproductive system works. Of course now we know that there is no such thing as a woman being Mazria. To be fair, Chazal probably knew that women do not produce seed. They probably used Mazria as a euphemism for ovulation. But the mistake is clear. Chazal believed that there was some kind of relationship between how one’s sex is determined and who “seeded” first. If a woman produced an ova first, then it is one sex. If the male produced the sperm first, then it the other.
There is absolutely no scientific basis for this. We now know how sex is determined. It is the x and y chromosomes. Nothing to do with what comes first, ova or sperm. It is an entirely random (or if you prefer, God ordained) process.
That Chazal attributed this to a mistaken understanding of natural phenomena, does not lessen their authority or greatness. Their redaction of Torah She Bal Peh is not in question. Though there are much Machlokes about exactly what that Mesorah actually was (e.g. Beis Hillel-Beis Shamai, Rava-Abaye, Rav-Shmuel) there is no dispute that the Halacha as we practice it is considered a binding and sacred transmission through the Gemarah, of Torah and Rabbinic law. Even the Conservative Movement acknowledges that.
One of the more famous instances of Chazal’s scientific mistakes is all of the Refuos… elixirs and treatments of disease. Blood letting was considered by Chazal to be so effective, that one could be Mechalel Shabbos for it. They believed it saved lives. And that is what the medical community believed well into the 19th century. Again... a mistake. We now know that bloodletting does nothing but weaken, not strengthen a seriously ill person.
One of the more troubling aspects of the ban on Rabbi Nosson Slifkin’s books is not the one most frequently spoken of… the age of the universe. It is his claim, backed up by Rishonim, that Chazal could have been wrong in matters of science. In fact, if I remember correctly they objected to that even more. But there is really no getting around the obvious questions. How can so many obvious mistakes be explained? Maybe one can squeeze out an answer here and there. …but maintaining Chazal’s every single pronouncement on matters of science is accurate science? I don’t know about that.
At this point, I will confess that I part company with my own Rebbi on this issue. He held that Chazal were completely infallible. And he went to great lengths trying to explain difficult Gemmros, like explaining that Mazikin are really bacteria …all to support the position that if it was brought down in the Gemarah then it’s true… or was true. I do not agree. One can explain some Gemaros that way but not al of them. I can’t personally accept that as a legitimate explantion. For me, it would entail a massive amount of intellectual dishonesty.
The explanation often put forth is Nishtaneh HaTevah, that nature has changed. …that during Chazal’s time those Refuos actually worked and that descriptions of how the natural universe worked were accurate only that for some of them nature has changed our own time.
But blood-letting? Isn’t it more reasonable to assume that since blood-letting was a legitimate medical treatment almost up to our own time it was simply mistakenly considered to be an effective medical treatment? …that it is not… a “change in nature? …that it was a simply a mistaken but widely accepted medical practice for centuries? I certainly think so.
