Chapter 11: Events, Qualities, Quantities, And Other Vague Words: On Lojban Abstraction

5. Amount abstractions

The following cmavo is discussed in this section:

ni  NU  amount abstraction

Amount abstractions are far more limited than event or property abstractions. They really make sense only if the selbri of the abstracted bridi is subject to measurement of some sort. Thus we can speak of:

✥5.1  le ni le pixra cu blanu [kei]
the amount-of (the picture being-blue)
the amount of blueness in the picture

because “blueness” could be measured with a colorimeter or a similar device. However,

✥5.2  le ni la djein. cu mamta [kei]
the amount-of (Jane being-a-mother)
the amount of Jane's mother-ness (?)
the amount of mother-ness in Jane (?)

makes very little sense in either Lojban or English. We simply do not have any sort of measurement scale for being a mother.

Semantically, a sumti with “le ni” is a number; however, it cannot be treated grammatically as a quantifier in Lojban unless prefixed by the mathematical cmavo “mo'e”:

✥5.3  li pa vu'u mo'e
    le ni le pixra cu blanu [kei]
the-number 1 minus the-operand
    the amount-of (the picture being-blue)
1 - B, where B = blueness of the picture

Mathematical Lojban is beyond the scope of this chapter, and is explained more fully in Chapter 18.

There are contexts where either property or amount abstractions make sense, and in such constructions, amount abstractions can make use of “ce'u” just like property abstractors. Thus,

✥5.4  le pixra cu cenba le ka ce'u blanu [kei]
the picture varies in-the property-of (X is blue)
The picture varies in being blue.
The picture varies in blueness.

is not the same as

✥5.5  le pixra cu cenba le ni ce'u blanu [kei]
the picture varies in-the amount-of (X is blue)
The picture varies in how blue it is.
The picture varies in blueness.

✥5.4 conveys that the blueness comes and goes, whereas ✥5.5 conveys that its quantity changes over time.

Whenever we talk of measurement of an amount, there is some sort of scale, and so the place structure of “ni” abstraction selbri is:

x1 is the amount of (the bridi) on scale x2
Note: the best way to express the x2 places of abstract sumti is to use something like “le ni … kei be”. See ✥9.5 for the use of this construction.