Lojban Wave Lessons/23

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Lojban Wave Lessons: Foreword | ← Lesson 22 | Lesson 23 | Lesson 24 →

Lesson 23: Negation

Sometimes, just saying what's the truth is not enough. Often, we want to specify what's not the truth, and we do this by using negation.

Negation in English mostly involves not, and is completely arbitrary and ambiguous. We, as Lojbanists, can't have that, of course, so Lojban contains an elegant and unambigious system for negating. What will be presented here are the official gold-standard rules. Disapproval of these "golden rules" concerning na is growing, and there is disagreement about what rule set should replace it. For now, I will stick with the official rules, and therefore, so will you, dear reader.

The first you need to know about is bridi negation, so called because it negates the bridi it's in, saying it's not true. The way to negate a bridi is to place na first in the sentence with a ku after it, or just before the selbri.

speni = x1 is married to x2 under convention x3

Thus: na ku le mi speni cu ninmu states that My spouse is not a woman. It states nothing about what my wife is, or if I even have a wife. It only states that I do not have a wife who is also a woman. This has an important implication: If the negation of a bridi is false, the bridi must be true: na ku le mi speni cu na ninmu must mean that I have both a spouse, and that she is a she.

It is possible to use bridi negations in all bridi, even the implicit bridi of descriptive sumti. lo na prenu can refer to anything non-human, whether it be a sphinx, a baseball or the property of appropriateness.

bau = sumtcita, from bangu: using the language of {sumti}
se ja'e = sumtcita, from se jalge: because of {sumti}

Often when using na, it's a problem that it negates the entire bridi. If I say mi na sutra tavla bau le glibau se ja'e le nu mi dotco, I end up negating too much, and it is not clear that I wanted to only negate that I speak fast. The sentence could suggest that I in fact speak fast because of some other reason, for instance that I speak fast in French because I'm German. To express the sentence more precisely, I need to only negate that I speak fast, and not the other things.

To only negate part of a bridi, na ku can be moved around the bridi and placed anywhere a sumti can go. It then negates any sumti, selbri and sumtcita placed after it. When placed immediately before the selbri, the ku can be elided.

Moving na ku from the left end of the bridi and rightwards effects any quantifiers in a certain way, as can be seen by this example:

There are forces within the Lojban community who, perhaps rightly, think that there is no good reason that a na placed before a selbri negates the entire bridi, whereas a na ku any other place negates only what is trailing behind it. However, in these lessons you will be taught what is still the official stance, namely that na before the selbri negates the bridi.

The use of na ku is exemplified with the following examples.

na ku ro remna cu verba It's not true that: All humans are children

su'o remna na ku cu verba For at least one human it's not true that: It's a child. See that the na ku is placed before cu, since a sumti can go only before, not after the cu. Had I only used na, it would have to go after cu - but that would have negated the entire bridi, meaning "It's not true that: At least one human is a child".

When the na ku is moved rightwards, any quantifier is inverted - that is: ro is turned into su'o. This is, of course, only if the meaning of the bridi has to be preserved. This means that when the na ku is placed at the end of the bridi, only the selbri is negated but all the sumti and sumtcita are preserved, as can be seen by these three identical bridi:

ckule = x1 is a school at location x2 teaching x3 to students x4 and operated by x5

na ku ro verba cu ve ckule fo su'o ckuleIt's not true that all children are students in a school.

su'o verba cu ve ckule na ku fo su'o ckuleSome children are students in not a single school.

su'o verba cu ve ckule fo ro ckule na kuSome children are for all schools not students in them.

The opposite of na is ja'a. This is barely ever used, since it is default in most bridi. One exception is repeated bridi (next lesson). Sometimes it's used to put more weight on the truth of the bridi, as in la .bab. ja'a melbi = "Bob is indeed beautiful".

While the mechanism of na ku resembles natural language negation, it can be difficult to keep track of exactly what is negated and how that affects the bridi. For that reason, the construct na ku is rarely seen anywhere other than the beginning of a bridi. In most cases where more specific negation is needed people resort to a different method. This method, called scalar negation, is an elegant and intuitive tool. Using it, you effect only the selbri, since the words used in scalar negation binds to the selbri much like the word se.

The name scalar negation is derived from the fact that the words which bind to the selbri can be placed along a scale from affirmation over negation and to stating that the opposite case is true:

These words are not negators in the same sense as na. They do not state that a bridi is false, but makes a positive statement that a bridi is true – the same bridi, but with a different selbri. This distinction is mostly academic, though. If, for example, I state that mi na'e se nelci "I am non-liked", I actually state that some selbri applies to me, which is also on a relevant scale with the selbri nelci. Most of the time, we assume a scale where the positions are mutually exclusive (like love-like-dislike-hate), so mi na'e se nelci implies mi na se nelci Therefore, the words no'e and to'e should only be used when the selbri is placed on some obvious scale: le mi speni cu to'e melbiMy spouse is ugly makes sense, since we immediately know what the opposite of beautiful is, while mi klama le mi to'e zdaniI go to my opposite thing of home, while grammatical, leaves the listener guessing what the speaker's opposite-home is and should be avoided. So how can you negate only the selbri without also implying that the selbri is correct at some other position on a truth-scale? Simple: Moving the na ku to the rightmost end of the bridi, as demonstrated a few lines above. This feature is very useful. Some Lojbanists prefer to prefix the rafsi nar (the rafsi of na) in front of the selbri - this has the same effect, but I advise against it, because it makes familiar brivla seem alien, and it's harder to understand when spoken casually. If a situation arises where you need to negate only the selbri, but want it to be clear before the end of the bridi, the experimental cmavo na'ei, which grammatically works like na'e, can be used na'ei: Negates the following selbri only Try to translate these sentences: My spouse is not a woman (meaning that he is a male) Answer: le mi speni cu na'e / to'e ninmu. Using scalar negation here implies that he exists, which na did not.My spouse is not really a woman Answer: le mi speni cu no'e ninmu. The scale here is presumed to be from woman to man.I don't speak fast in English because I'm German Answer: mi na'e sutra tavla bau le glibau se ja'e le nu mi dotco Also, note that whenever these words are used together with a tanru, they only affect the leftmost selbri. In order to make it bind to the whole tanru or parts of the tanru, the usual tanru-grouping words can be used. Try to say I sell something which is not yellow homes using the tanru pelxu zdani vecnu Answer: mi na'e ke pelxu zdani ke'e vecnu or mi na'e pelxu bo zdani vecnu When attempting to answer: Is the king of the USA fat?, all of these negations fail. While it's technically correct to negate it with na, since it makes no assumptions of that is true, it's mildly misleading since it could lead the listener to believe there is a king of the USA. For these scenarios, there is a metalinguistic negator, na'i.
na'i = metalinguistic negator. Something is wrong with assigning a truth value to the bridi.
Because na'i can be needed anywhere it has been given the grammar of the attitudinals, which means it can appear anywhere, and it attaches to the previous word or construct.
palci = x1 is evil by standard x2
le na'i pu te zukte be le skami cu palci
The sought goal {mistake!} of the computer was evil, probably protests that computers can seek a goal volitionally.

Since this is a lesson on negation, I believe the word nai deserves a short mention. It is used to negate minor grammatical constructs, and can be used in combination with attitudinals, all sumtcita including tenses, vocatives and logical connectives. The rules for negating using nai depend on the construct, and so the effect of nai has been discussed when mentioning the construct themselves. The exception is sumtcita, where the rules for negation are more complex, and will not be discussed here.

Note: At the time of writing, it has been proposed to move nai to the selma'o CAI, which means the semantics of nai depend on which selma'o it follows.

Lojban Wave Lessons: Foreword | ← Lesson 22 | Lesson 23 | Lesson 24 →