[lojban] djuno lo jei

[Thomas Jack <thomasjack@gmail.com>]

coi rodo

Example 7.3 in chapter 11 of the CLL is:

{mi djuno le jei la frank. cu bebna}
"I know the truth-value of Frank being a fool."

It is noted that this means that "I know whether or not Frank is a fool."

Similarly we have example 7.6:
{mi kucli le jei la frank. cu bebna}
"I am curious about how true it is that Frank is a fool."

These examples seem strange to me. In section 6 of chapter 11, it is
said that "the 'jei' abstraction refers to a number between 0 and 1
inclusive (as distinct from 'ni' abstractions, which are often on
open-ended scales)."

(aside: Could we similarly say:
{mi djuno le ni le pixra cu blanu}
"I know the amount of blueness in the picture"?)

{lo jei la frank. cu bebna} is a truth-value, a number between 0 and 1
inclusive. Let's say Frank is really, truly, absolutely a fool.
Wouldn't it be correct, then, that {lo jei la frank. cu bebna cu du li
pa}? If so, is it then true that {mi djuno li pa}? Suppose also that
Jane is really, trully, absolutely brilliant, so that {lo jei la djein
cu mencre cu du li pa}. Then, is it true that {mi djuno lo jei la jein
cu mencre}? I might not even know Jane! Whether or not we can actually
get the {du li pa}s here, the truth-values of these sentences are
certainly the same, so this last absurdity should be true, right? (A
similar problem happens for {ni} abstractions used in this way, if
they can be used in this way at all.)

I think I would want to translate "I know whether Frank is a fool" as
{mi djuno lo du'u makau jei la frank cu bebna} (similarly for {ni}).

In general, given a sumti in a top-level bridi (certainly not
abstracted, and perhaps there are other ways to get out of the
"top-level", I dunno), and given that we have an identity statement
about that sumti, can we substitute salva veritate in the original
bridi? I feel like we should be able to. For example if {da broda} is
true, and {da du de} is true, then {de broda} should also be true.

ki'e mi'e tomoj


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