Re: tech:logic matters

[ucleaar <ucleaar@UCL.AC.UK>]

John:
> la .and. cusku di'e
> > In summary: The real dispute between you & the rest of lojbania
> > is not about whether "(Ax Fx) -> (Ex Fx)" is true (I am willing to
> > accept that it is). Rather, the dispute is about whether lojban
> > quantification is restricted or unrestricted: you say it is
> > restricted, and the rest of lojbania says it is unrestricted.
> I stand with pc here:  the whole purpose of "da poi ... ku'o" constructs
> is to represent the restricted quantification of Aristotelian logical
> forms. The fact that "all men are mortal" is equivalent to "for all X,
> if X is a man then X is mortal" is a theorem, not a mere convention of
> rewriting.

In logic, I trust you mean.

> My recent proposal that "ro prenu" means "ro da poi prenu" (and not
> "ro lo prenu") restores the original pre-Lojban situation.

But hang on. The {ro prenu/ro lo prenu} distinction concerns the dogbiting
issue. Now you're saying that {ro prenu} = {ro da poi kea prenu} &
pc says the latter means there are prenu, so you're also making the
{ro prenu/ro lo prenu} distinction do existential import too. Is that
what you really want?

> &: but maybe there are great virtues to restricted quantification that I
> am failing to recognize
> pc: Let's see:
> They are the quantifiers of natural language, the ones grammars are
> designed to deal with (arguable for the universal, the particular,
> finite numerals and the plurative -- though less in the last case; not
> for the majoritive or any of the rest)

That's open to debate, and decisions for lojban shouldn't depend on
resolution of that debate. I (naively?) thought that logic is relatively
well understood, while natural language is relatively ill understood,
and hence some of the appeal of lojban is that it is based principally
on logic.

> They give a unified treatment for all the quantifiers, even the ones
> that do not fit with the unrestricted cases, even ones -- like "enough"
> that do not fit with the cases that "do not fit," even the unrestricted
> ones.  (Lojban, by the way, has a pretty good -- but far from
> reasonably exhaustive list of these critters -- it could use a little
> jazzing up)

That's a virtue only if you belive all those other so-called quantifiers
are a good thing. I don't. (I mean I think it's fine for all these
words to be in PA, but the formal metalanguage should contain only
existential and universal quantifiers, in order to minimize the number
of primitives.)

> They can fit most neatly into (Lojban's -- but most languages')
> syntax, forming a unit that occupies the place of  an argument, rather
> than a functionally fractionated and incomplete creature like the
> standard logical correlate (a quantifier, a predicate, and half a
> conditional)

That's not a pure semantics argument. It's an argument about correspondence
between syntax and semantics; but if the correspondence is bad, it's the
syntax we should blame. Meaning comes first.

> The first and last of these can be dealt with in various ways, the
> second provably cannot.  And this means that items with the same
> grammar in Lojban have different logics, yet another blow (but this
> is largely beating a dead horse) to the claim that Lojban is a logical
> language: _su'o_ may be a modern unrestricted quantifier, but _so'e_
> cannot be.

Its logicality is the existence of rules for going from syntax to a
relatively well-understood and well-specified logic. Any logicality
arising from the regularity of those rules is an added bonus.

> &: But why should {suo no lo ro broda} mean that there are brodas?
> pc: Because the internal _ro_, properly understood, says that there
> are some brodas, even if none of them do whatever the predication goes
> on to claim.

That's what I don't understand.

coo, mie and