daf bit: (prompted by) Zevachim 50

[cellio]

Today's daf has a long discussion of how some of the rules of talmudic reasoning relate to each other, drawing examples from the laws concerning the temple service. In lieu of that discussion (which does not fit in the margins of this daf bit), I offer a summary of the rules cited on this daf:

• Kal v'chomer: I learned this as the "how much the moreso" argument, but it literally means "simple and complex" "lenient and strict" (thanks for the correction). This is the argument that says that if such-and-such (simple, minor) behavior is a problem, then surely thus-and-such amplified version of it is. I understand that there is support for running the logic in the other direction too, though I don't know how that works.
• Gezeirah shavah: this is an analogy drawn between two uses of the same word in torah. If the word means such-and-such when used here, then it must mean such-and-such when used over here too, and you can use this reasoning to clarify ambiguous interpretations. I am told that originally this rule applied only in cases where a word appears exactly two times, but that doesn't seem to be the case any more.
• Hekkesh: this is an analogy based on facts rather than words, and is sometimes described as being related to the gezeirah shavah. If I understand correctly, this is the rule that's in play when you see reasoning like "if we do such-and-such for a sin offering, then we must do the same thing for a wholeness offering".

The daf also refers to binyan av, which has something to do with a passage serving as a standard for interpreting others, but I lack good examples or a clearer understanding. (There are more rules too; these are just the ones discussed here.)

Comments

[530nm330hz.livejournal.com]

I'd consider kal vachomer "lenient and strict" rather than "simple and complex." These are, after all, the same roots as kulah and chumrah. "If X is forbidden even in the lenient case, it must be forbidden in the more restrictive case."

A backwards kal vachomer is a contrapositive. If X is permitted in a strict case, then it must certainly be permitted in a lenient case.

A gezerah shava is specifically restricted to places where we have a received tradition. That is, you and I can't say "ooh, look, the word 'tov' appears in these two places, so the halachot are the same!" Gezerah Shavas generally come in pairs, even if the word/phrase occurs elsewhere. This is not to be confused with the principle of "Two teachings that come as one do not teach anything." (I.e., if the same law is explained in two places in Torah, that doesn't make it the basis for extrapolating to a general rule.)

It's not so much that it explains what a word means; it's a particular technique which basically says "We have a received tradition back to Moshe that: because the word X is used in the Torah both in the explanation of case A and in the explanation of case B, certain laws that explicitly appear in the Torah's explanation of case A also apply to case B, and possibly vice versa."

I have never grokked how hekkesh works.

[cellio]

Thanks for the correction on kal vachomer. I stupidly recognized the wrong word in "kal" and failed to recognize chumrah in chomer, which I certainly should have.

A gezerah shava is specifically restricted to places where we have a received tradition.

Oh, good. Because otherwise that would seem to have all sorts of potential for chaos, and I was wondering why I didn't see more of that.