Did Rabbi Akiva accept arguments from ignorance?

Question

There's a common principle found in various academic disciplines, that absence of proof does not equal proof of absence (ie: a lack of evidence for something doesn't mean that it does not exist). I am often reminded of Eduyos 2:2 and Zevachim 12:4, in which the chakhomim tell Rabbi Akiva that "אין לא ראינו ראיה" ("We did not see it" is not a proof).

Given, however, that the chakhomim had to say this to Rabbi Akiva, and given that he did just use it as a proof, does that mean that Rabbi Akiva didn't hold to this principle?

Did Rabbi Akiva believe that not ever having seen something accounted to an argument in favour of that thing's non-existence?

Answer 1

1. Absence of proof is not proof of absence, but it is a strong indicator of absence
2. The degree to which "לא ראינו" is an indication of absence depends on the size of the domain. If we are dealing with the whole planet as the domain, but our area of observation is only our local vicinity, then absence of proof is a very poor indicator for the whole domain. If our area of observation covers the full domain, then it is a strong indication of absence, but still not a proof.
3. Rabi Chanina's observation covered many years of Temple activity, which was the relevant domain. His lack of observation was a very strong indicator that the non-observed behavior was halachically precluded, and that is why he did not observe it.
4. Halachically we rarely require proof, we only need a strong indication ("חזקה", or related concepts). Even two witnesses is far from being a proof, but it is accepted absolutely.

R' Akiva believed that the "לא ראינו" of Rabbi Chanina was sufficient to be a halachic basis for determining that it was a matter of law, while the Chachamim argued that it was not an acceptable basis even as an indicator of likelihood.