11.7. Predication/sentence abstraction

The following cmavo is discussed in this section:



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:

Example 11.42. 

I know that Frank is a fool.

How's that in Lojban? Let us try:

Example 11.43. 


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; Example 11.43 comes close to claiming that Frank's being-a-fool is purely a mental activity on the part of the speaker. (In fact, Example 11.43 is an instance of improperly marked sumti raising, a concept discussed further in Section 11.1).

Try again:

Example 11.44. 


I know the truth-value of Frank being a fool.

Closer. Example 11.44 says that I know whether or not Frank is a fool, but doesn't say that he is one, as Example 11.42 does. To catch that nuance, we must say:

Example 11.45. 


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.) Example 11.46 has no such implied assertion:

Example 11.46. 


I am curious about whether Frank is a fool.

and here du'u could probably be replaced by jei without much change in meaning:

Example 11.47. 


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:

du'u x1 is the predication (the bridi), expressed in sentence x2

and le se du'u ... is very useful in filling places of selbri which refer to speaking, writing, or other linguistic behavior regarding bridi:

Example 11.48. 

la.djan.cucuskulese du'u

John says that George goes to the store.

Example 11.48 differs from

Example 11.49. 


John says George goes to the store.

because Example 11.49 claims that John actually said the quoted words, whereas Example 11.48 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 Section 11.1 for a discussion of lu'e.)