Lojban is an engelang. It has explicit design goals, and expressing predicate logic is the first of them. Whether or not it meets its design goals is another matter.

English is a natlang. It has no design goals.

Pete Bleackley
The Fantastical Devices of Pete The Mad Scientist -
Emily Semantic Recommendation -

-----Original Message-----
From: Gleki Arxokuna <[log in to unmask]>
To: [log in to unmask]
Sent: Thu, 22 Oct 2015 7:25 am
Subject: Re: Lojban is not based on predicate logic (a recent paper)

2015-10-21 22:43 GMT+03:00 R A Brown <[log in to unmask]>:

> On 21/10/2015 20:11, And Rosta wrote:
>> On 21 Oct 2015 14:15, "Gleki Arxokuna" wrote:
>>> 2015-10-19 0:40 GMT+03:00 And Rosta
>>> I think you've really proved my point, Gleki: you're
>>>>  probably the world's only human being who can
>>>> interpret that passage from John Clifford as meaning
>>>> that there is no meaningful sense in which Lojban is
>>>> based on predicate logic.
>>> okay one more quotation from the reference grammar
>>> itself:
>>> "There are many more aspects of logic that I neither
>>> fully understand nor feel competent to explain, neither
>>> in abstract nor in their Lojban realization. Lojban was
>>> designed to be a language that makes predicate logic
>>> speakable,
> ... which in my understanding of English (which, I admit,
> I've been speaking for only about 74 years) this means the
> language is _based_ on predicate logic!  The design is the
> basis is it not?
> and achieving that goal completely will need to wait
>>> for someone who understands both logic and Lojban
>>> better than I do.
> Does Gleki not understand the difference between base and a
> goal - the start and the finish that one is aiming for, the
> alpha and the omega?  It may well not have (yet) achieved
> the goal of making predicate logic _completely_ speakable -
> that's the goal.  But by saying "completely" does not the
> writer imply that it has at least been _partially_ completed?
> In Chapter 1 of the Lojban Reference Grammar we we are told
> quite unambiguously:
> "Lojban grammar is based on the principles of predicate logic."
> See:
> Cannot we all just accept what the Lojban Reference Grammar
> so clearly and unambiguously states and stop this pointless
> argument?

Consider I write a new grammar of English stating "It is based on predicate
Will you believe me?

Why should we believe some original research and call Lojban "based on
predicate logic" because the authors just want to?

I can only agree that the reference grammar of Lojban asserts something but
is it a linguistic fact?
And even if it's just a historical fact (loglang by history, not by fact)
then this history has to be described (which Loglan1 textbook might do to
some extent).

> I can only hope to have pointed out the areas that are
>>> well-understood (and by implication, those that are
>>> not)."
>>> If Lojban were based on predicate logic making tha
>>> tlogic speakble would be trivial.
> I'm lost - I do not follow the reasoning here.
> [snip]
>> We don't disagree about Lojban and its relation to logic.
>> I intervened in the thread only because you were
>> interpreting the meaning of "based on" in a way that was
>>  both eccentrically narrow and, without your
>> interlocutors necessarily realizing it, different from
>> their more everyday and latitudinous interpretation of
>> the term.
> Certainly different from the way I understand the word.  The
> _basis_ is what one starts from.
> Your subsequent messages have described the ways Lojban
>> both is and isn't based on PL, and I expect that in
>> consequence all your readers now have a fairly clear
>> understanding of the relationship between Lojban and
>> logic.
> Yes, I rather fancy we have      :)
> --
> Ray
> ==================================
> ==================================
> "Ein Kopf, der auf seine eigenen Kosten denkt,
> wird immer Eingriffe in die Sprache thun."
> [J.G. Hamann, 1760]
> "A mind that thinks at its own expense
> will always interfere with language".