From Lojban List, 8 November 2002:
The position supported by everybody except pc (= me, xorxes, Jordan, Adam, Nick , xod + probably Robin — everybody who's participated, & probably the remainder of Lojbanists too) is this:
A. ro broda cu brode = ro da poi broda cu brode
B. ro da poi broda cu broda = ro da ga na broda gi brode
C. ro broda cu brode = ro da ga na broda gi brode
- B should read ro da poi broda cu brode, right?
- Yup. --jrd
- Do you mean ga na or ga nai? --pne
- Those are the same. --jrd
The position supported by pc is that C is definitely invalid, while either one of A and B may be declared valid, with the other one declared invalid (though his preference is for A to be valid and B to be invalid).
The pros and cons of the two positions have already been debated, so I won't try to summarize them.
Each position is partially but not fully consistent with CLL (which itself is not internally consistent). Contrary to what pc seems often to be saying, each position is equally compatible with logic, for the point at issue concerns which logical formula the linguistic structures correspond to.
The debate about whether the universal quantifier and/or ro is importing is pretty much a red-herring, because it boils down to a question of the effect of an empty universe on truth values*. It is a matter that your average Lojbanist interested only in precise and unambiguous communication can safely ignore.
Neither position really has anything to do with logic. It has to do with the mapping between linguistic and logical structures. The choice really boils down to (a) which one makes the grammar simplest, (b) which one better matches established usage and established idiolects, (c) which one better matches the way we each would like things to be.
How, then, do we choose between the two positions?
CLL gives equal support to each, so is not decisive here. Each position is equally compatible with general lojbanological principles. There is no firmly established common lojbanic lore on the matter. The evidence for this is that if the A=B=C position had been firmly established, then we wouldn't be having the debate — pc would go on complaining but nobody would heed it, except perhaps to point out that he was wrong
, while if pc's position had been firmly established, then he would not be the only one espousing it at the least, several other jboskepre ought to be backing him up.
All we can do is note that pc takes the one position and everybody else the other. There is, then, a pc-less consensus in favour of A=B=C. IMO, when an issue has been as thoroughly debated as this, and a pcless consensus emerges, it counts as a pukka consensus, and it is eligible to made Official if/when the time comes to document it in official publications.
I therefore propose to document A=B=C on the wiki as a pcless consensus. If that turns out to be premature, it can be revised.
- As i (mi'e maikl.) said here: "I think the jbojbe may end up using ganai with the understanding (call it logical etiquette) that they are not to use this with a counterfactual clause. (There are, after all, other ways to express those kinds of statements.)"
- Are you suggesting that ganai, gi should only be used when the former bridi is known to be true, flattening the concept into "ja'o"? --xod