Chapter 11: Events, Qualities, Quantities, And Other Vague Words: On Lojban Abstraction
7. Predication/sentence abstraction
The following cmavo is discussed in this section:
du'u NU predication abstraction
There are some selbri which demand an entire predication as a sumti; they make claims about some predication considered as a whole. Logicians call these the “propositional attitudes”, and they include (in English) things like knowing, believing, learning, seeing, hearing, and the like. Consider the English sentence:
✥7.1 I know that Frank is a fool.
How's that in Lojban? Let us try:
✥7.2 mi djuno le nu la frank. cu bebna [kei] I know the event of Frank being a fool.
Not quite right. Events are actually or potentially physical, and can't be contained inside one's mind, except for events of thinking, feeling, and the like; ✥7.2 comes close to claiming that Frank's being-a-fool is purely a mental activity on the part of the speaker. (In fact, ✥7.2 is an instance of improperly marked “sumti raising”, a concept discussed further in c11-§10).
✥7.3 mi djuno le jei la frank. cu bebna [kei] I know the truth-value of Frank being a fool.
Closer. ✥7.3 says that I know whether or not Frank is a fool, but doesn't say that he is one, as ✥7.1 does. To catch that nuance, we must say:
✥7.4 mi djuno le du'u la frank. cu bebna [kei] I know the predication that Frank is a fool.
Now we have it. Note that the implied assertion “Frank is a fool” is not a property of “le du'u” abstraction, but of “djuno”; we can only know what is in fact true. (As a result, “djuno” like “jei” has a place for epistemology, which specifies how we know.) ✥7.5 has no such implied assertion:
✥7.5 mi kucli le du'u la frank. cu bebna [kei] I am curious about whether Frank is a fool.
and here “du'u” could probably be replaced by “jei” without much change in meaning:
✥7.6 mi kucli le jei la frank. cu bebna [kei] I am curious about how true it is that Frank is a fool.
As a matter of convenience rather than logical necessity, “du'u” has been given an x2 place, which is a sentence (piece of language) expressing the bridi:
- x1 is the predication (the bridi), expressed in sentence x2
7.6.5) la djan. cusku le se du'u la djordj. klama le zarci [kei] John expresses the sentence-expressing-that George goes-to the store John says that George goes to the store.
✥7.6 differs from
✥7.7 la djan cusku lu la djordj. klama le zarci li'u John expresses, quote, George goes to the store, unquote. John says “George goes to the store”.
because ✥7.7 claims that John actually said the quoted words, whereas ✥7.6 claims only that he said some words or other which were to the same purpose.
“le se du'u” is much the same as “lu'e le du'u”, a symbol for the predication, but “se du'u” can be used as a selbri, whereas “lu'e” is ungrammatical in a selbri. (See Chapter 5 for a discussion of “lu'e”.)