Q&A: The Rule of “Dayo” in an Inference from a Kal Va-Chomer
The Rule of “Dayo” in an Inference from a Kal Va-Chomer
Question
Why, in the Rabbi’s view, do the Sages not accept Rabbi Tarfon’s a fortiori argument regarding damage caused by an ox’s horn in the injured party’s domain: “If in a place where the law is lenient regarding tooth and foot—namely, the public domain—it is stringent regarding horn, then in a place where the law is stringent regarding tooth and foot—namely, the injured party’s domain—is it not all the more so that we should be stringent regarding horn? They said to him: It is enough for that which comes from an inference to be like that from which it is inferred: just as in the public domain it pays half-damages, so too in the injured party’s domain it pays half-damages.” But seemingly, in this case the a fortiori argument that is formed is in fact valid, since the lenient case is foot relative to horn (and this is learned from the public domain), and then with respect to the injured party’s domain, even within the framework of the principle of “dayo,” horn should still incur full damages.
Answer
It’s hard for me to explain this in words. Essentially there are two formulations of this a fortiori argument: one leads to liability for half-damages, and the other leads to liability for full damages. The question is why the Sages do not agree to adopt the result of the one that yields full damages. Seemingly, it should be enough that there is one argument that proves full damages in order to obligate him. The second argument does not prove liability for half-damages, but rather for at least half—and full damages also meets that criterion.
The analysis of this a fortiori argument in tabular form shows the view of the Sages, but this is not the place for it. That analysis appears in the second article on the logical hermeneutical principles:
מידות הדרש ההגיוניות כאבני הבסיס להיסקים לא דדוקטיביים – חלק ב’
Discussion on Answer
You’re repeating the question I raised here. I explain it there, but right now I don’t have time to get into it.
I tried to read it, but I think I didn’t understand. After all, it’s clear that even when mapped onto the prism of the different domains, horn in the injured party’s domain is supposed to be more severe than in the public domain; we just don’t know by how much. So I don’t understand why there is any tension, or any need to choose between the presentation of “at least half,” based on the domains, and the presentation of “at least one,” once we have established the hierarchy between tooth and foot on the one hand and horn on the other.