Affirmative and negative
In linguistics and grammar, affirmative and negative are terms of opposite meaning which may be applied to statements, verb phrases, clauses, and some other utterances. Essentially an affirmative (positive) form is used to express the validity or truth of a basic assertion, while a negative form expresses its falsity. Examples are the sentences "Jane is here" and "Jane is not here"; the first is affirmative, while the second is negative.
The grammatical category associated with affirmative and negative is called polarity. This means that a sentence, verb phrase, etc. may be said to have either affirmative or negative polarity (its polarity may be either affirmative or negative). Affirmative is generally the unmarked polarity; the negative is marked by a negating word or particle such as the English not, German nicht, Swedish inte, and so on, which reverses the meaning of the predicate. The process of converting affirmative to negative is called negation – the grammatical rules for negation vary from language to language, and a given language may have more than one way of producing negations.
Affirmative and negative responses (especially, though not exclusively, to questions) are often expressed using particles such as yes and no, where yes is the affirmative and no the negative particle.
Affirmative and negative responses
Special affirmative and negative words (particles) are often found in responses to questions, and sometimes to other assertions by way of agreement or disagreement. In English, these are yes and no respectively, in French oui and non, in Swedish ja and nej, and so on. Not all languages make such common use of particles of this type; in some (such as Welsh) it is more common to repeat the verb or another part of the predicate, with or without negation accordingly.
Complications sometimes arise in the case of responses to negative statements or questions; in some cases the response that confirms a negative statement is the negative particle (as in English: "You're not going out? No."), but in some languages this is reversed. Some languages have a distinct form for yes given in response to a negative, such as French si and Swedish jo (these serve to contradict the negative statement suggested by the first speaker).
Grammatical rules for negation
Simple negation of verbs and clauses
- Está en casa. ("(S)he is at home", affirmative)
- No está en casa. ("(S)he is not at home", negative)
Other examples of negating particles preceding the verb phrase include Italian non, Russian не nye and Polish nie (they can also be found in constructed languages: ne in Esperanto and non in Interlingua). In some other languages the negating particle follows the verb or verb phrase, as in Dutch:
- Ik zie hem. ("I see him", affirmative)
- Ik zie hem niet. ("I do not see him", negative)
Particles following the verb in this way include not in archaic and dialectal English ("you remember not"), nicht in German (ich schlafe nicht, "I am not sleeping"), and inte in Swedish (han hoppade inte, "he did not jump").
In French, particles are added both before the verb phrase (ne) and after the verb (pas):
- Je sais ("I know", affirmative)
- Je ne sais pas ("I don't know", negative).
However in colloquial French the first particle is often omitted: Je sais pas. Similar use of two negating particles can also be found in Afrikaans: Hy kan nie Afrikaans praat nie ("He cannot speak Afrikaans").
In standard Modern English, negation is achieved by adding not after an auxiliary verb (which here means one of a special grammatical class of verbs that also includes forms of the copula be; see English auxiliaries). If no such verb is present then the dummy auxiliary do (does, did) is introduced – see do-support. For example:
- I have gone → I have not gone (have is the auxiliary)
- He goes → He does not go (no auxiliary in the original sentence)
Different rules apply in subjunctive, imperative and non-finite clauses. For more details see English grammar: Negation. (In Middle English, the particle not could follow any verb, e.g. "I see not the horse.")
In some languages, like Welsh, verbs have special inflections to be used in negative clauses. (In some language families, this may lead to reference to a negative mood.) An example is Japanese, which conjugates verbs in the negative after adding the suffix -nai (indicating negation), e.g. taberu ("eat") and tabenai ("do not eat"). It could be argued that English has joined the ranks of these languages, since negation requires the use of an auxiliary verb and a distinct syntax in most cases; the form of the basic verb can change on negation, as in "he sings" vs. "he doesn't sing". Zwicky and Pullum have shown that n't is an inflectional suffix, not a clitic or a derivational suffix.
Complex rules for negation also apply in Finnish; see Finnish grammar: Negation of verbs. In some languages negation may also affect the dependents of the verb; for example in some Slavic languages, such as Russian, the case of a direct object often changes from accusative to genitive when the verb is negated.
Negation of other elements
Negation can be applied not just to whole verb phrases, clauses or sentences, but also to specific elements (such as adjectives and noun phrases) within sentences. Ways in which this can be done again depend on the grammar of the language in question. English generally places not before the negated element, as in "I witnessed not a debate, but a war." There are also negating affixes, such as the English prefixes non-, un-, in-, etc. Such elements are called privatives.
Specialized negatives and double negatives 
There also exist elements which carry a specialized negative meaning, including pronouns such as nobody, none and nothing, determiners such as no (as in "no apples"), and adverbs such as never, no longer and nowhere.
Although such elements themselves have negative force, in some languages a clause in which they appear is additionally marked for ordinary negation. For example, in Russian, "I see nobody" is expressed as я не вижу никого ja nye vizhu nikovo, literally "I don't see nobody" – the ordinary negating particle не ("not") is used in addition to the negative pronoun никого ("nobody").
In standard English, however, as in other Germanic languages, this does not ordinarily occur – the presence of a negative element is sufficient to mark the clause as negative without any need for generic negation with not. For example:
- I never go there.
- No children were present in the building.
An alternative is to negate the clause with not, but to use the affirmative equivalent (a negative polarity item) of the other negative element:
- I don't ever go there.
- There weren't any children in the building. (but not *Any children were not present...; the de-negated element cannot precede the negation)
Similarly, when the clause would contain more than one specialized negative, all but the first are changed to their affirmative equivalents (or all of them if the sentence is negated with not):
- You never take anybody (not: nobody) anywhere (not: nowhere).
- You don't ever take anybody anywhere.
In a language such as Russian, all of the elements ("not", "never", "nobody", "nowhere") would appear together in the sentence in their negative form. In French, where simple negation is performed using ne ... pas (see above), specialized negatives appear in combination with the first particle (ne), but pas is omitted:
- Je ne bois jamais ("I never drink")
- Je ne vois personne ("I see nobody")
- Je n'ai jamais vu personne ("I have never seen anybody")
In colloquial English, however, the construction with not together with another negative (or with multiple negative elements) is quite commonly encountered, although prescriptivists regard it as ungrammatical. This is called a double negative. For example:
- I don't want to go nowhere. (standard English: I don't want to go anywhere)
- I never told him nothing. (standard English: I never told him anything)
Double negatives are nonetheless sometimes found in standard English when one negative is intended to negate the other:
- I don't know nothing (meaning "It is not true that I know nothing")
However such constructions are often awkward, and the prevalence of double negatives in some colloquial speech means that they are likely to be ambiguous: "I don't know nothing" may also be interpreted to have its colloquial meaning of simply "I know nothing".
In Ancient Greek, a simple negative (οὐ or μὴ) following another simple or compound negative (e.g. οὐδείς "nobody") results in an affirmation, whereas a compound negative following a simple or compound negative strengthens the negation:
- οὐδείς οὐκ ἔπασχε τι, "nobody was not suffering something", i.e. "everybody was suffering"
- μὴ θορυβήσῃ μηδείς, "let (not) nobody raise an uproar", meaning "let nobody raise an uproar"
Double negation (where one negative cancels the other) is also found in the figure of speech known as litotes, which is a form of understatement, as in "She is not unattractive".
For more information, see the article Double negative.
Meaning of negation
Simple grammatical negation of a clause in principle has the effect of converting a proposition to its logical negation – replacing an assertion that something is the case by an assertion that it is not the case.
In some cases, however, particularly when a particular modality is expressed, the semantic effect of negation may be somewhat different. For example, in English, the meaning of "you must not go" is not in fact the exact negation of that of "you must go" – this would be expressed as "you don't have to go" or "you needn't go". The negation "must not" has a stronger meaning (the effect is to apply the logical negation to the following infinitive rather than to the full clause with must). For more details and other similar cases, see the relevant sections of English modal verbs.
For the use of double negations or similar as understatements ("not unappealing", "not bad", etc.) see litotes.
- Zwicky, Arnold M.; Pullum, Geoffrey K. (1983), "Cliticization vs. Inflection: English n't", Language (Linguistic Society of America) 59 (3): 502–513, doi:10.2307/413900, JSTOR 413900
- The linguist D. Biber refers to two types of negation, synthetic ('no', 'neither' or 'nor' negation) and analytic ('not' negation). For example, "He is neither here nor there" (synthetic) or "He is not here" (analytic).
- Laurence R. Horn, A Natural History of Negation. 2001. ISBN 978-1-57586-336-8
- Douglas Biber, Susan Conrad, Randi Reppen, "Corpus Linguistics: Investigating Language Structure and Use". 1998. ISBN 0-521-49957-7
- Marco Tettamanti, Rosa Manenti - Pasquale A. Della Rosa - Andrea Falini - Daniela Perani - Stefano F. Cappa and Andrea Moro (2008) "Negation in the brain. Modulating action representation." NeuroImage Volume 43, Issue 2, 1 November 2008, Pages 358-367. http://dx.doi.org/10.1016/j.neuroimage.2008.08.004