Those who know little else about the Hazon Ish know that he held that the length of an ammah (forearm to the tips of your fingers) is 58 centimeters (about 23 inches). Now unless you're Shaquille O'Neal, your forearm is probably a lot closer to 46 centimeters (about 18 inches) long, which is Rav Chaim Naeh's approximation of the ammah. So what's the deal with the Hazon Ish? Way back when I promised to deal with this. Today's the day.

Most people haven't actually read the Hazon Ish's comments on the topic (found in his chiddushim on Orach Chaim, siman 39, commonly called kunteres hashiurim) and therefore assume that the Hazon Ish believes the following two propositions:

1. When the halacha invokes an ammah, the reference is to the ancient ammah, the length of which (in terms of some "objective" measure such as centimeters) we are under obligation to reconstruct.

2. Ancient forearms (and eggs, etc.) were considerably larger than today's.

Admit it. Both of these propositions seem absolutely pig-headed. A forearm ought to be a forearm and an egg ought to be an egg -- we shouldn't be in the archeology business. Moreover, as long as we are being forced into the archeology business, there isn't a shred of evidence that people or eggs were once larger than they are today. In fact, all evidence indicates that they were a bit smaller.

It turns out, though, that the Hazon Ish is getting a bum rap here because, in fact, he does not believe either of the above propositions.

Before I get to what he actually believes, a brief digression concerning a popular misconception about the Hazon Ish, generally. Those who don't know better imagine him to have been a frightening and forbidding character. First of all he wore those scary black glasses frames and in the few well-known images of him, he does seem to be affecting that Litvak scowl. More to the point, though, his many followers in Bnei Brak have a well-deserved reputation as being to the frum world what mathematicians are to the academic word: convinced of their intellectual superiority, in the grip of a world-view that permits only black and white and possessing social skills that suggest a mild case of Asperger's syndrome.

Nevertheless, the Hazon Ish was, by all accounts, nothing like that. Unlike most of today's roshei yeshiva, the Hazon Ish did not feel the need to dress the part (in the name of "kavod hatoirah"). He dressed like a simple Jew and legends abound of people who hadn't met him before assuming that he was just that. Saul Lieberman, who was his first cousin and with whom he often hung out in Minsk, tells a hilarious story about the time the Hazon Ish was learning in a small beis midrash in Minsk and the shammes pulled his gemara out from under him and said "the daf yomi learners need this gemara and, anyway, a simple Jew like you should be saying Tehillim". When the shammes realized what he had done and tried to apologize, the Hazon Ish was apparently bewildered about what necessitated an apology. Last week, Rav Usher told of a rav who was seated next to the Hazon Ish at some event and, not recognizing him, asked him if he learns gemara. The Hazon Ish answered, "ven ich hob zeit, lern ich".

Anyway, back to our story about eggs and forearms. As I was saying, the Hazon Ish actually rejects both of the silly propositions mentioned above. First of all, he cites the opinion of R. Yosi in Mishnah Keilim 17:6 that a "medium" egg is determined "according to the opinion of the observer". This, says the Hazon Ish, proves that rabbinic measures are subjective. But precisely because room was left for human judgment in such matters, poskim in each generation have the privilege of replacing earlier standards of measurement with ones they find more appropriate. And once they have done so, the earlier measurements are entirely irrelevant. This must be so, he adds, because it would be absurd for us to have to recover ancient measures.

So much for the first proposition. Now where did that long ammah come from? Well both the forearm and the egg are correlated already in the gemara with the width (or thickness) of the thumb. The ammah is defined as equivalent to 24 thumbs and the volume of the egg to 10.8 cubic thumbs. The Noda Beyehuda chose to use the thumb as the most fundamental of these measures and, on the basis of his measurements of thumbs, concluded that the ammah must be equivalent to 13 Russian vershoks (1 vershok = 4.445 centimeters). Thus, concludes the Hazon Ish, once the Noda Beyehuda made that determination, the new standard is not thumbs, forearms or eggs, but rather vershoks.

Of course, the mappings from eggs to cubic thumbs and from thumbs to vershoks leaves one with a virtual egg that is equivalent to a lot more cubic vershoks than any actual egg anybody ever saw. Interestingly, the Hazon Ish hints that he is aware that no such large egg ever existed. He writes, "Truth and error are irrelevant since the matter was handed over to the opinion of the observer and the opinion of the observer here means the consensus of leaders of the generation who have so determined. And whatever they decided is true [by definition] and that is the standard."