NEGATION AND GENERALIZED QUANTIFIERS Frans Zwarts ...
NEGATION AND GENERALIZED QUANTIFIERS Frans Zwarts ...
NEGATION AND GENERALIZED QUANTIFIERS Frans Zwarts ...
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<strong>NEGATION</strong> <strong>AND</strong> <strong>GENERALIZED</strong> <strong>QUANTIFIERS</strong><br />
<strong>Frans</strong> <strong>Zwarts</strong><br />
Centre for Behavioural, Cognitive and Neuro-sciences<br />
Rijksuniversiteit Groningen<br />
1. Introduction<br />
Linguistic research has clearly shown that natural languages exhibit different forms of<br />
negation. Foremost among these are sentence negation and predicate negation. In this<br />
study, the relationship between both will be discussed. In particular, it wiu be argued<br />
that we can give an accurate description of the logical connections between sentence<br />
negation and predicate negation by reference to the semantical nature of the subject<br />
noun phrase. To this end, two important classes of generalized quantifiers will be<br />
distinguished, having to do with the familiar logical notions of consistency and<br />
completeness. Next, it will be shown that the distribution of negative adverbs in<br />
languages as Dutch and German forces us to make a distinction between predicate<br />
negation and verb negation as well. The logical relationship between these two forms<br />
of negation appears to be the same as that between sentence negation and predicate<br />
negation. Finally, it will be demonstrated that the difference between predicate negation<br />
and verb negation also shows up in languages such as English, particularly in co~ection<br />
with monotonicity patterns.<br />
2. Consistency<br />
It is well-known that there are considerable differences between sentential negation, an<br />
the one hand, and predicate negation, on the other. Less known is the fact that the<br />
logical relationship between both forms of negation depends entirely on the semantical<br />
nature of the subject. In order to convince ourselves, we do well to take the following<br />
two examples into consideration.<br />
(1) a At least two willows do not flower +<br />
It is not the case that at least two willows flower<br />
b Most weeping willows do not flower 4<br />
It is not the case that most weeping willows flower<br />
One sees immediately that the conditional in (la) can not be regarded as valid. For if<br />
the state of affairs is such that of the seven willows only four happen to flower, then the<br />
antecedent is true, but the consequent false. On the other hand, it is evident that the<br />
conditional in (lb) must be accepted as valid. If we are willing to accept the truth of the<br />
statement Most weeping willows do not flower, then we shall also have to acknowledge<br />
that it is not the case that the majority of weeping willows flowers. This entails that the<br />
quantifier which is associated with noun phrases of the form most N is invariably<br />
consistent in nature - consistent in the sense that it cannot contain a given set of
individuals as well as the complement of that set. For the sake of clarity we give the<br />
following definition.<br />
(2) Definition<br />
Let B be a Boolean algebra. A quantifier Q on B is said to be consistent iff<br />
for each element X of the algebra B: if -X E Q, then X # Q.<br />
Noun phrases which invariably receive a consistent quantifier as their semantic value,<br />
will accordingly be referred to as consistent noun phrases.<br />
The property of consistency can of course be formulated in more than one way. Indeed,<br />
it is readily established that the law of contraposition allows us to replace the definition<br />
in (2) by the alternative characterization in (3).<br />
(3) Definition<br />
Let B be a Boolean algebra. A quantifier Q on B is said to be consistent iff<br />
for each element X of the algebra B: if X E Q, then -X 4 Q.<br />
In spite of this equivalence, we prefer the definition in (2), primarily because it affords<br />
us a handy way of establishing the corollary below.<br />
(4) Corollary<br />
A noun phrase is consistent iff the following schema is logically valid:<br />
(1) NP (NEG VP) -, NEG (NP VP)<br />
This simple result is important, because it clearly shows that with a consistent noun<br />
phrase as subject the use of predicate negation invariably entails sentence negation.<br />
From the fact that the implication in (lb) is valid, it follows immediately that noun<br />
phrases of the form most N are consistent. Do not suppose that this exhausts the matter,<br />
for one easily proves that proper names and expressions of the forms both N, the n N,<br />
the NG and the N must also be regarded as belonging to the class of consistent noun<br />
phrases. In the &flowing examples, the use of predicate negation invariably entails<br />
sentence negation.<br />
(5) a Themistocles does not mourn<br />
It is not the case that Thernistocles mourns<br />
b Both feet are not ulcerated<br />
It is not the case that both feet are ulcerated<br />
c The seventeen donkeys do not bray<br />
It is not the case that the seventeen donkeys bray<br />
d The scientists do not drink coffee<br />
It is not the case that the scientist drink coffee<br />
e The shopkeeper does not waste time<br />
It is not the case that the shopkeeper wastes time
Similarly, one easily shows that expressions of the forms neither N, none of the n N and<br />
none of the N are also consistent in nature. To this end, it is enough to take the<br />
conditionals in (6) into consideration.<br />
(6) a None of the six donkeys does not bray<br />
It is not the case that none of the six donkeys brays<br />
b Neither foot is not ulcerated<br />
It is not the case that neither foot is ulcerated<br />
c None of the scientists does not waste time<br />
It is not the case that none of the scientists wastes time<br />
That each of these entailments is valid, follows from the definitions of the quantifiers<br />
corresponding to the noun phrases in question. To give an example, if none of the<br />
scientists does not waste time, then it follows that they all waste time, which in turn<br />
means that it is not the case that none of them wastes time. Consequently, the<br />
conditional in (6c) must be accepted as valid.<br />
The foregoing observations by no means imply that every noun phrase is consistent. The<br />
invalid implication in (1) clearly shows that expressions of the form at least n N do not<br />
belong to this class. In an analogous manner, one easily proves that noun phrases of the<br />
forms all N and no N can also not be regarded as consistent,, The next two examples,<br />
if interpreted as cases of regular negation, are both invalid.<br />
(7) a All students do not complain<br />
It is not the case that all students complain<br />
b No child does not complain<br />
It is not the case that no child complains<br />
By way of an illustration, it should be noted that, when the universe does not contain<br />
any child, the statements No child complains and No child does not complain are both<br />
true, which means that the denial It is not the case that no child complains must be<br />
regarded as false. Similarly, if the universe happens to lack students, the two statements<br />
All students complain and All students do not complain must both be accepted as true,<br />
and hence the denial It is not the case that all students complain must be rejected as<br />
false.<br />
In this connection, the behaviour of partitive noun phrases is rather interesting. It<br />
requires no lengthy reflection to see that expressions of the form at least n of the k N<br />
are consistent iff n > k/2. As a special case of the general pattern we have the valid<br />
conditional in (8).<br />
(8) At least three of the four children do not complain 3<br />
It is not the case that at least three of the four children complain<br />
On the other hand, if we consider expressions of the form (exactly) n of the k N, then<br />
the property of consistency appears to manifest itself just in case n f k/2. That is to say:<br />
(9) a Six of the eight children do not complain<br />
It is not the case that six of the eight children complain<br />
b One of the eight children does not complain
It is not the case that one of the eight children complains<br />
Finally, it should be easy to see that noun phrases of the form at most n of the k N are<br />
consistent only if n < k/2. In other words:<br />
(10) At most one of the four children does not complain +<br />
It is not the case that at most one of the four children complains<br />
The logical behaviour of partitive expressions thus appears to show some regularities.<br />
These find expression in three general laws concerning the phenomenon of consistency.<br />
(11)<br />
Laws of consistency for partitive' expressions<br />
(1) Expressions of the form at least n of the k N are consistent iff n > k/2.<br />
(2) Expressions of the form (exact&) n of the k N are consistent iff n # k/2.<br />
(3) Expressions of the form at most n of the k N are consistent iff n < k/2.<br />
We must therefore conclude that, with a substantial number of partitive subject phrases,<br />
the use of predicate negation implies sentence negation.<br />
With the aid of the foregoing test we can usually arrive at rather trustworthy judgments<br />
when it comes to deciding whether a given noun phrase does or does not enjoy the<br />
property of consistency. For the sake of clarity the outcomes of the test have been<br />
collected in table 1. The eighteen classes of noun phrases mentioned there must all be<br />
regarded as consistent. Such a catalogue, though at first sight merely of encyclopedic<br />
value, is important because we shall soon see that it leads to a coherent and complete<br />
account of the relationship between sentence negation and predicate negation.<br />
It should be pointed out in this connection that the property of consistency shows a<br />
striking resemblance to the logical theorem known as the law of contradiction. Indeed,<br />
the principle in question is meant to exclude the possibility that two contradictory<br />
propositions are both accepted as true. For that reason it is usually stated as '-(p A<br />
-p)'. One sees immediately that the property of consistency is similar to the logical<br />
theorem in that it excludes that two sets X and -X both belong to the quantifier. It will<br />
become apparent that this state of affairs has far-reaching consequences for our views<br />
on the different forms of negation.<br />
3. Completeness<br />
It requires no lengthy reflection to realize that the property of consistency has a<br />
counterpart. In order to convince ourselves, we take the following two examples into<br />
account.<br />
(12) a It is not the case that most tulips flower<br />
Most tulips do not flower<br />
b It is not the case that Seneca plays chess<br />
Seneca does not play chess
Table 1: Eighteen classes of consistent noun phrases.<br />
most N<br />
the majority of the N<br />
at least n of the k N (n > k/2)<br />
(exactly) n of the k N (n f k/2)<br />
at most n of the k N (n < k/2)<br />
both N<br />
the n N (n =. 0)<br />
the more than n N (n > 0)<br />
the no more than n N (n > 0)<br />
the Npl<br />
the Nsg<br />
neither N<br />
none of the n N (n > 0)<br />
none of the more than n N (n > 0)<br />
none of the no more than n N (n > 0)<br />
none of the N<br />
proper names<br />
negated proper names<br />
Clearly, the conditionaI in (124 cannot be regarded as valid. For if the state of affairs<br />
in the universe is such that half of all tulips flowers, then the antecedent is true, but the<br />
consequent false. On the other hand, the conditional sentence in (12b) surely belongs<br />
to the class of valid statements. If we accept the truth of the statement It zk not the case<br />
that Senecaplays chess, then we will also have to accept that Seneca does not play chess.<br />
Tbis entails that the quantifiers which are associated with proper names invariably are<br />
complete in nature - complete in the sense that it cannot be that neither the<br />
complement of a given set nor that set itself is a member of the quantifier in question.<br />
For the sake of accuracy we record this in the form of a definition.<br />
(1 3) Definition<br />
Let B be a Boolean algebra. A quantifier Q on B is said to be complete iff for<br />
each element X of the algebra B: if X & Q, then -X E Q.<br />
It is evident that the notion of completeness just introduced is the reversal of the notion<br />
of consistency mentioned before. This means that there are alternative characterizations<br />
of the property in question. Indeed, it is easily established that the law of contraposition<br />
allows us to replace the conditional in (13) by the equivalent statement 'if -X # Q, then<br />
X E Q'. Yet, we shall stick to the original definition, primarily because of the following<br />
corollary.<br />
(14) Corollary<br />
A noun phrase is complete if£ the following schema is logically valid:<br />
(1) NEG (NP VP) -* NP (NEG VP3<br />
This elementary result is important because it expresses in a lucid way that with a<br />
complete noun phrase as subject the use of sentence negation invariably implies<br />
predicate negation.<br />
From the fact that the implication in (12b) is valid, it follows immediately that proper<br />
names are complete. In an analogous way, one easily shows that negated proper names
are also complete in nature. This does not exhaust the stock, for a short search produces<br />
several other cases of completeness. The next two examples serve as an illustration.<br />
(15) a It is not the case that at least half of all tulips flowers -3<br />
At least half of all tulips does not flower<br />
b It is not the case that at most half of all cows has died<br />
At most half of all cows has not died<br />
There can be no doubt that both conditionals are valid. Indeed, if we accept the truth<br />
of the statement It is not the case that at least half of all tulips flowers, then we shall also<br />
have to accept that at least half of all tulips does not flower. Similarly, it is easily<br />
established that anyone who accepts the statement It is not the case that at most half of<br />
all cows has died as true will also be committed to the truth of At most half of all cows<br />
has not died. Consequently, we must conclude that noun phrases of the forms at least<br />
half of all N and at most half of all N both belong to the class of complete expressions.<br />
For the sake of clarity, these results have been collected in table 2. One sees<br />
immediately that two of the four classes of noun phrases mentioned are also consistent,<br />
namely proper names and their negations. This is important, because it follows from the<br />
relevant definitions that with a consistent and complete noun phrase as subject the use<br />
of sentence negation is equivalent to predicate negation. For that reason, the<br />
biconditional in (16) must be regarded as valid.<br />
(16)<br />
It is not the case that Themistocles mourns<br />
Themistocles does not mourn<br />
Indeed, it follows from the completeness of the expression Themistocles that the use of<br />
sentence negation entails predicate negation. Conversely, the consistent nature of the<br />
element in question guarantees that the use of predicate negation implies sentence<br />
negation. In this way, we can give a semantic explanation of the at first sight rather<br />
intricate relationship between both forms of negation.<br />
4. Sentence negation and predicate negation<br />
'I therefore hold it more suitable to regard negation as marking the content of apossible<br />
judgment." In this way, Frege expresses in the fourth paragraph of Begn~sschrifr his<br />
conviction that the different forms of negation must all be regarded as sentence<br />
negation. Of course, such a view entails that the use of predicate negation must also be<br />
reduced to sentence negation. In the posthumous fragment 'Logic', which dates from<br />
1897, he states this very clearly: 'In the German language we usually indicate that a<br />
thought is false by inserting the word 'not7 into the predicate.'2 To be sure, there are<br />
moments at which Frege expresses himself more carefully, as in the unpublished<br />
fragment 'Introduction to Logic' (1906), where we read:<br />
Frege (1980: 4).<br />
Frege (1979: 149).
-- -<br />
Table 2: Four classes of complete noun phrases.<br />
at least half of all N at most half of all N<br />
proper names negated proper names<br />
'To think is to grasp a thought. Once we have grasped a thought, we can recognize it as<br />
true (make a judgement) and give expression to our recognition of its truth (make an<br />
assertion). Assertoric force is to be dissociated fiom negation too. To each thought there<br />
corresponds an opposite, so that rejecting one of them is accepting the other. One can<br />
say that to make a judgment is to make a choice between opposites. Rejecting the one<br />
and accepting the other is one and the same act. Therefore there is no need of a special<br />
name, or special sign, for rejecting a thought. We may speak of the negation of a<br />
thought before we have made any distinction of parts within it. To argue whether<br />
negation belongs to the whole thought or to the predicative part is every bit as unfruitful<br />
as to argue whether a coat clothes a man who is already clothed or whether it belongs<br />
together with the rest of his clothing. Since a coat covers a man who is already clothed,<br />
it automatically becomes part and parcel with the rest of his apparel. We may,<br />
metaphorically speaking, regard the predicative component of a thought as a covering<br />
for the subject-component. If further coverings are added, these automatically become<br />
one with those already there."<br />
But that does not alter the fact that Sommers is absolutely right when he claims that<br />
Frege's way of portraying the matter rests on 'the negatability criterion for genuine<br />
subjecthood'? According to this criterion, the status of logical subject can only be<br />
assigned to a given phrase if attachment of two contradictory predicates to the<br />
expression in question will give us two contradictory propositions. In other words, should<br />
we wish to speak of a logical subject, then the use of predicate negation must in Frege's<br />
opinion invariably be equivalent to sentence negation. It is evident that such a<br />
requirement entails that proper names be assigned a separate place, for on the basis of<br />
the fact that Aristotle is not a philosopher is the denial of Aristotle is a philosopher, Frege<br />
labels the occurrence of Aristotle in both sentences as the logical subject. On the other<br />
hand, he refuses to regard the occurrence of all mammals in All mammals we land-<br />
dwellers as the logical subject, because the statement All mammals are not land-dwellers<br />
clearly cannot be classified as the denial of All mammals are land-dwellers. Indeed, his<br />
remarks in 'On Concept and Object' show that Frege is not even willing to analyze the<br />
expression all marnmak as a logical unit3 In this way, he withholds logical<br />
Frege (1979: 185).<br />
Sommers (1982: 27).<br />
Frege (1980: 47-48) offers us the following explanation: 'We may say in brief, taking 'subject and<br />
'predicate' in the linguistic sense: A concept is the reference of a predicate; an object is something that<br />
can never be the whole reference of a predicate, but can be the reference of a subject. It must here be<br />
remarked that the words 'all', 'any', 'no', 'some', are prefixed to concept-words. In universal and particular<br />
affirmative and negative sentences, we are expressing relations between concepts: we use these words to<br />
indicate the special kind of relation. They are thus, logically speaking, not to be more closely associated
constituenthood from phrases that grammar considers to be unsuspected units, and<br />
creates an unbridgeable gap between logical form, on the one hand, and grammatical<br />
form, on the other. Whether Frege was really content with this solution is not clear, for<br />
at the end of the posthumous fragment 'Logic' he concludes that the use of the word not<br />
'in ordinary language is a purely external criterion and an unreliable one at that7, and<br />
complains about the fact that 'we are tangling with some thorny problems hereY.'<br />
The difficulties that Frege experiences can be attributed to the fact that he sticks to a<br />
first order analysis of sentences. If we give up this restriction and regard noun phrases<br />
as second order expressions, then any doubt a. to the relationship between sentence<br />
negation and predicate negation must disappear. For it can be described completely in<br />
terms of the earlier mentioned properties of consistency and completeness. To forestall<br />
any misunderstandings, we do well to express this in the form of two general laws<br />
concerning the use of both forms of negation.<br />
(17)<br />
Laws of negation (preliminary version)<br />
(1) The use of sentence negation implies predicate negation just in case the<br />
subject of the sentence is complete in nature.<br />
(2) The use of predicate negation implies sentence negation just in case the<br />
subject of the sentence is consistent in nature.<br />
It goess without saying that, in the presence of a subject which is complete and<br />
consistent, the use of sentence negation is equivalent to predicate negation.<br />
4. The theory of quaternality<br />
There are other formulations of the laws of negation which are perhaps less obvious, but<br />
completely equivalent to the original formulations. To this end, we shall introduce three<br />
operations which, applied to given quantifiers, produce new quantifiers. Starting from<br />
a quantifier Q on a Boolean algebra B, the first enables us to form the complement of<br />
Q, that is to say, the quantifier consisting of all elements of the algebra B which do not<br />
belong to Q. This new quantifier will be written as -Q. With the aid of the second<br />
operation we form the so-called contradual of Q, represented by the symbol -Q. This<br />
is the quantifier which consists of all elements X of the algebra B such that -X E Q. The<br />
third operation, finally, serves to create a new quantifier -Q- which we call the dual of<br />
with the concept-words that follow them, but are to be related to the sentence as a whole. It is easy to<br />
see this in the case of negation. If in the sentence<br />
'all mammals are land-dwellers'<br />
the phrase 'all mammals' expressed the logical subject of the predicate are land-dwellers, then in order<br />
to negate the whole sentence we should have to negate the predicate: 'are not land-dwellers'. Instead, we<br />
must put the 'not' in front of 'all'; from which it follows that 'all' logically belongs with the predicate.' The<br />
reader should note that Frege (1979: 87-117) contains a preliminary draft of the article.<br />
' Frege (1979: 150).
Q. It contains each element X of the algebra B such that -X $ Q. For the sake of<br />
transparency we record this in the form of a definition.'<br />
(18) Definition<br />
Let B be a Boolean algebra and let Q be a quantifier on B. Then:<br />
(1) The complement of Q is the quantifier -Q = {X E B: X 4 Q).<br />
(2) The contradual of Q is the quantifier Q- = {X E B: -X E Q).<br />
(3) The dual of Q is the quantifier -Q- = {X E B: -X 4 Q).<br />
One sees immediately that it makes no difference whether we regard the dual -Q- as the<br />
complement of the contradual of Q or as the contradual of the complement of Q. For<br />
this reason we write -Q- instead of -(Q-) or (-Q)-. It is also readily established that the<br />
complement of the complement of Q, the contradual of the contradual of Q, and the<br />
dual of the dual of Q are all identical to Q. In symbols: --Q = Q-- = --Q--= Q.<br />
Likewise, one easily shows that the contradual of the dud of Q is equal to the<br />
complement of Q, and that the complement of the dual of Q is equal to the contradual<br />
of Q. That is to say: -Q-- = -Q and --Q- = Q-.<br />
duals +<br />
complements<br />
-Q-<br />
Figure 1<br />
contraduals<br />
contraduals<br />
complements<br />
-, duals<br />
With the aid of these equations, we can visualize the mutual relationships between Q, -<br />
Q, Q- and -Q- by means of the picture in figure 1. The square represented there shows<br />
a clear resemblance with the traditional square of opposition.2 As an illustration of this<br />
The model-theoretic notion of the dual of a quantifier is discussed in Barwise and Cooper (1981:<br />
197). Among other things, they call attention to the important subclass of self-dual quantifiers, defined<br />
by the equation Q = -Q-.<br />
Gottschalk (1953) points out that every involution in a logical or mathematical system gives rise<br />
to a theory of quaternality and that the square of quaternality, of which the classical squares of opposition<br />
are special cases, provides a diagrammatic representation for much of this theory.<br />
45 1
correspondence, we consider the noun phrases all weasels (Q), not all weasels (-Q), no<br />
weasel (Q-), and at least one weasel (-Q-). By reference to the square it is readily<br />
established that all weasels and at least one weasel are each other's duals, just as not all<br />
weasels and no weasel are. Similarly, we can show that not all weasels is the contradual<br />
of at least one weasel and that no weasel is the contradual of all weasels. The expressions<br />
at least one weasel and no weasel, finally, must be regarded as each other's complements.<br />
Indeed, it requires no lengthy reflection to realize that every noun phrase determines a<br />
square of opposition. For this reason we are entitled to say that an expression as neither<br />
ox is the contradual of both oxen.<br />
The significance of such squares of opposition lies in the fact that they enable us to give<br />
an alternative characterization of the properties of consistency and completeness. The<br />
next two lemmata provide the necessary details.<br />
(19) Lemma<br />
(20) Lemma<br />
Let B be a Boolean algebra. The following two statements about a quantifier<br />
Q on B are equivalent:<br />
(1) Q is consistent.<br />
(2) Q c -Q-.<br />
Proof. Suppose that Q is consistent and that X E Q. Then -X # Q, and so, by<br />
the definition of duality, X E -Q-. Hence, Q c -Q-. Conversely, if Q c -Q- and<br />
X E Q, then X E -Q-. SO, by the definition of duality, -X # Q. II<br />
Let B be a Boolean algebra. The following two statements about a quantifier<br />
Q on B are equivalent:<br />
(1) Q is complete.<br />
(2) -Q- r Q.<br />
Proof. Suppose that Q is complete and that X E -Q-. Then -X # Q, by the<br />
definition of duality, and so X G Q, by the completeness of Q. Hence, -Q- r<br />
Q. Conversely, if X # Q, then X # -Q-, because of (2), and so, by the definition<br />
of duality, -X E Q. II<br />
From this it follows that a quantifier which is both consistent and complete is self-dual.<br />
That is to say:<br />
(21) Corollary<br />
Let B be a Boolean algebra. The following two statements about a quantifier<br />
Q on B are equivalent:<br />
(1) Q is consistent and complete.<br />
(2) Q = -Q-.<br />
The above result provides us with two tests. For it is easily established that quantifiers<br />
which are consistent and complete have the property that -X belongs to Q iff X does not<br />
belong to Q. But from the fact that Q is self-dual in such cases we may also infer that
X belongs to Q iff -X does not belong to Q. As a consequence, we have the following<br />
corollary:<br />
(22) Corollary<br />
A noun phrase is consistent and complete iff the following schemata are<br />
logically valid:<br />
(1) NEG (NP VP) - NP (NEG VP)<br />
(2) NP VP NEG (NP (NEG VP))<br />
That proper names, regarded as consistent and complete noun phrases, satisfy the first<br />
requirement has already been established by means of the valid equivalence in (16).<br />
That they also satisfy the second requirement is shown by the validity of the<br />
biconditional in (23).<br />
(23) Themistocles mourns +<br />
It is not the case that Themistocles does not mourn<br />
Consequently, we may conclude that proper names belong to the class of expressions<br />
which are self-dual.<br />
In view of these findings, the earlier formulations of the laws of negation may be given<br />
a different form. Instead of saying that in the presence of a consistent subject the use<br />
of predicate negation implies sentence negation, it is possible to say that the subject<br />
should be contained in its dual if the use of predicate negation is to imply sentence<br />
negation. Conversely, it is necessary that the subject contains its dual if the use of<br />
sentence negation is to imply predicate negation. This is expressed in the following law<br />
concerning equivalent forms of negation.<br />
(24) Equivalent forms of negation<br />
The use of sentence negation is equivalent to predicate negation just in case<br />
the subject is consistent and complete, that is to say, just in case the subject<br />
is self-dual.<br />
It will be shown that this rather surprising relationship between negation and duality is<br />
significant in other respects as well.<br />
5. Laws of negation<br />
With the aid of the theory of quaternality, we can establish a number of simple facts<br />
concerning the mutual relationships between Q, -Q, Q- and -Q-.<br />
(25) Theorem<br />
Let B be a Boolean algebra. The following statements about a quantifier Q on<br />
B are equivalent:<br />
(1) X # Q.
The importance of this elementary result lies in the fact that it enables us to provide<br />
several alternative characterizations of the use of sentence negation. The next corollary<br />
gives the relevant details. It should be emphasized that we write NpN for the<br />
complement of a noun phrase, NP' for the contradual of a noun phrase, and N P for ~<br />
the dual of a noun phrase.<br />
(26) Laws of negation I<br />
The following schemata are logically equivalent:<br />
(1) NEG (NP VP)<br />
(2) N P (NEG ~ VP)<br />
(3) NPN W<br />
(4) NEG (NP' (NEG W))<br />
It should be obvious that, in the presence of a self-dual subject, the use of sentence<br />
negation is equivalent to predicate negation. If there is no such subject, the transition<br />
from sentence negation to predicate negation or from predicate negation to sentence<br />
negation must involve the replacement of the subject by its dual. As a special case of<br />
this general law, we have the logical equivalence of It is not the case that every cow moos,<br />
At least one cow doesn't moo, Not every cow moos, and It is not the case that no cow<br />
doesn't moo.<br />
Do not suppose that this exhausts the matter, for the square of opposition depicted in<br />
figure 1 also permits us to derive the logical equivalences in (27) - (29).<br />
(27) Laws of negation I1<br />
The following schemata are logically equivalent:<br />
(1) NEG (NPD VP)<br />
(2) NPpG VP)<br />
(3) NP VP<br />
(4) NEG ( NP~ (NEG VP))<br />
(28) Laws of negation 111<br />
The following schemata are logically equivalent:<br />
(1) NEG (NPC VP)<br />
(2) N P (NEG ~ VP)<br />
(3) NPD VP<br />
(4) NEG (NP (NEG VP))<br />
(29) Laws of negation TV<br />
The following schemata are logically equivalent:<br />
(1) NEG (NP~ VP)<br />
(2) N P (NEG ~ W)
(3) NP VP<br />
(4) NEG (NP~ (NEG VP))<br />
As an illustration of these laws, it is sufficient to observe that the proposition It is not<br />
the case that at least one cow moos is equivalent to Every cow doesn 't moo, No cow moos<br />
and It is not the case that not every cow doesn't moo by the four schemata in (27). This<br />
is important because it shows clearly that a sentence can be denied in several ways. The<br />
idea of a one-to-one correspondence between positive and negative sentences, once<br />
suggested by Kraak (1966: 81), must therefore be immediately discarded.<br />
5. Verb negation<br />
Thus far, we have assumed that there are only two types of negation - sentence negation<br />
and predicate negation. As should be evident to anyone who is familiar with the word<br />
order of Dutch and German subordinate clauses, there exists a third type as well - to<br />
wit, verb negation1 By way of an example, consider the Dutch sentence in (30).<br />
(30)<br />
Ik weet dat hij veel opgaven niet begrijpt.<br />
I know that he many problems not understands<br />
'I know that there are many problems which he doesn't understand.'<br />
Clearly, the scope of the negative adverb niet 'not' is the transitive verb begnypt<br />
'understands' alone. This contrasts sharply with the example in (31), where the scope of<br />
niet is either the direct object veel opgaven 'many problems' or the entire verb phrase<br />
veel opgaven begrijpt.<br />
(31)<br />
Ik weet dat hij niet veel opgaven begrijpt.<br />
I know that he not many problems understands<br />
'I know that he doesn't understand many problems.'<br />
At first sight, the possibility of verb negation seems to be restricted to languages such<br />
as Dutch and German. However, when one takes the distribution of some and any into<br />
consideration, it becomes clear that English has this type of negation as well. The next<br />
two conditionals may serve as an illustration.<br />
(32) John didn't see any of the paintings .-,<br />
John didn't see any of the modern paintings<br />
(33)<br />
John didn't see some of the modem paintings<br />
John didn't see some of the paintings<br />
The validity of the entailment in (32) shows that the object noun phrase is the argument<br />
' of a monotone decreasing function. This is not the case in (33), where the direction of<br />
the conditional inference is in fact the opposite of what we saw before. In other words,<br />
Brown (1991) argues that the Scots spoken in Hawick also exhibits verb negation. One of his<br />
examples is He's still no working ('It is the case that he is still out of work'), where the position of the<br />
negative after the adverb still unambiguously indicates that the scope is the main verb.
the object noun phrase in (33) must be the argument of a monotone increasing function.<br />
In what follows, we will show that this can be explained if we assume that the<br />
occurrence of some of the modem paintings in (33) is the argument of the negative<br />
transitive verb phrase didn't see. Before we address this matter in more detail, we do<br />
well to establish some simple facts concerning the logical relationship between predicate<br />
negation and verb negation.<br />
By means of the theory of quaternality, we can provide several alternative ways of<br />
characterizing predicate negation. To show this, we assume (1) that extensional transitive<br />
verbs are of type (e, (e, t)), being associated with two-place relations between<br />
individuals; (2) that object noun phrases, like subject noun phrases, are generalized<br />
quantifiers of type ((e, t), t); and (3) that the combination of an extensional transitive<br />
verb with denotation R and an object noun phrase with denotation Q is to be<br />
interpreted as the set {a E U: {b E U: R(a,b)) E Q), where U is the universe of<br />
discourse.' In terms of these principles and the result established in (25), we can prove<br />
that the set {a E U: {b E U: R(a,b)) + Q), which corresponds to predicates of the form<br />
NEG (V NP), is identical to the sets {a E U: {b E U: R(a,b)) E -Q-), {a E U: {b E U:<br />
R(a,b)) E -Q), and {a E U: {b E U: R(a,b)) 4 Q-). The following lemma, which is an<br />
obvious extension of the result obtained in (26), gives the necessary linguistic details.<br />
For the sake of transparency, we present two versions - one for SVO-languages, the<br />
other for SOV-languages.<br />
(34) Laws of negation V<br />
The following schemata are logically equivalent:<br />
S VO- languages SOV-languages<br />
(1) NP (NEG (V (1) NP (NP V))<br />
(2) NP ((NEG V) NP (2) NP (NP (NEG V))<br />
(3) NP (v NP*) (3) NP (NP~ V)<br />
(4) NP (NEG ((NEG V) NP~)) (4) NP (NEG (NP~ (NEG v)))<br />
It should be clear that, in the presence of a simple transitive verb and a self-dual object,<br />
the use of predicate negation is equivalent to verb negation. If there is no such object,<br />
the transition from predicate negation to verb negation or from verb negation to<br />
predicate negation must involve the replacement of the object by its dual. As a special<br />
case of this general law, we have the logical equivalence of John (didn't (solve every<br />
problem)) and John ((didn't solve) some problem (s)) .<br />
Van Benthem (1986) seems to have been one of the first to propose such a treatment. In defense<br />
of this approach, he points out that extensional transitive verbs are sensitive to the semantic structure of<br />
the object noun phrase. If the expression in question is monotone decreasing, as in John ate or drank<br />
nothing, we may legitimately pass to John ate nothing or John &mk nothing. On the other hand, if the<br />
object is monotone increasing, as in John heard and felt something, we may legitimately pass to John<br />
heard something or John felt something. A more elaborate discussion of this matter can be found in<br />
Hoeksema (1989, 1991a, 1991b) and van Benthem (1991). Keenan (1989) proposes a slightly different<br />
treatment of subject and object noun phrases, based on what he refers to as semantic case. His approach<br />
is adopted by <strong>Zwarts</strong> (1991), in connection with a unified treatment of reflexives and noun phrases.
This does not exhaust the matter, for the theory of quaternality also permits US to derive<br />
the lemmata in (35) - (37).<br />
(35) Laws of negation VI<br />
The following schemata are logically equivalent:<br />
S VO-languages SO V- languages<br />
(1) NP (NEG (V wD)) (1) NP (NEG (NP~ V))<br />
(2) NP ((NEG V) NP) (2) NP (NPJrnG V))<br />
(3) NP (v NP~) (3) Np (Np V)<br />
(4) NP (NEG ((NEG V) NP~)) (4) NP (NEG ( NP~ (NEG v))<br />
(36) Laws of negation VII<br />
The following schemata are logically equivalent:<br />
v))<br />
(1) NP (NEG (V NP'A) (1) Np PC<br />
(2) Np ((NEGDV) Np 1 (2) Np (5 (NEG V))<br />
(3) NP (V NP ) (3) NP (Np v)<br />
(4) NP (NEG ((NEG V) NP)) (4) NP (NEG (NP (NEG V))<br />
(37) Laws of negation VIII<br />
The following schemata are logically equivalent:<br />
SVO-languages S 0 V- languages<br />
(1) NP (NEG (V NP~J) (1) NP (NEG ( NF~ v))<br />
(2) NP ((NEG V) NP ) (2) NP (NPc (NEG V))<br />
(3) NP (V NP) (3) NP (NP V)<br />
(4) NP (NEG ((NEG V) NP~)) (4) NP (NEG (NP* (NEG V))<br />
As an illustration of these laws, it is sufficient to observe that the English proposition<br />
John (didn't (solve any of the problems)) is equivalent to John ((didn't solve) all of the<br />
problems) and John (solved none of the problems) by the SVO-schemata (I), (2) and (3)<br />
in (35).' The SOV-patterns can be exemplified by means of the logically equivalent<br />
Dutch propositions Ik weet dat zzj' (niet (alle opgaven heeft opgelostt)) 'I know that she<br />
(didn't (solve all of the problems))', Ik weet dat zij (mixstem 6dn opgnve (niet heeft<br />
opgelost)) 'I know that she ((didn't solve) some of the problems)', ik weet dat zij ((niet<br />
It is much more dicult to find an instance of the fourth schema in (351, due to the absence of<br />
sentences with more than one preverbal negation in standard E~ghsh. Brown (1991: 82, 84, 85) reports<br />
cases involving two or even three negations in Hawick Scots, among them He couldnae have been no<br />
working 'It is impossible that he has been out of work', He could no have been no working 'It is possible<br />
that he has not been out of work', and He couldnae have no been no working 'It is impossible that he<br />
has not been out of work'.
Figure 2<br />
PUF, > u~~<br />
alle opgaven) heeff opgelost 'I know that she (solved not all of the problems)', and Ik weet<br />
dat zij (niet (geen enkele opgave (niet heeft opgelost))). It should be clear that the<br />
schemata in (26) - (29), on the one hand, and those in (34) - (37), on the other, can be<br />
combined in various ways. The proposition It is not the case that everyone solved some<br />
of the problems, for example, is equivalent to Someone (didn't (solve some of the<br />
problems)) and Someone ((didn't solve) all of the problems) by the schemata (1) and (2)<br />
in (26) and (34).<br />
6. The semantics of extensional transitive verbs<br />
In their Boolean Semantics for Natural Language (1985), Keenan and Faltz describe a<br />
way of endowing extensional verbs and verb phrases with a third-order Boolean<br />
structure. The approach advocated there contrasts in interesting ways with the first-<br />
order treatment of the same expressions in Keenan (1989). In this section, their<br />
proposals are summarized and related to the analysis presented in Partee and Rooth<br />
(1983).<br />
For Keenan and Faltz, as for many others, generalized quantifiers are sets of sets of<br />
individuals, belonging to what is commonly referred to as the universe of NP<br />
denotations, written UNP. The Boolean operations in this type are of course union,<br />
intersection and complementation. Keenan and Faltz give a special status to NP<br />
denotations corresponding to individuals. If the individual i is an element of the universe<br />
U, the corresponding quantifier is the set {X c U: i E U}, known as the principal<br />
ultrafilter generated by i. The set {PUF(i): i E U) of principal ultrafilters corresponding<br />
to individuals is denoted PUFU.
As Partee and Rooth (1983) show, PUF has a useful property: it is a set of so-called<br />
free generators for the Boolean algebra &.' This means that each element of UNp can<br />
be represented as a Boolean combination of elements of PUFu and that any function<br />
g from Uw to an arbitrary Boolean algebra B can be extended uniquely to a<br />
homomorphism h from UNp to B. Pictorially, the situation can be represented as in<br />
figure 2, where i is the inclusion map of PUFu into UNP.<br />
Following in essence Partee and Rooth (1983), we can now describe the higer-order<br />
Boolean structure that Keenan and Faltz assign to the space of extensional transitive<br />
verbs and verb phrases, which they take to be Ho%(UW Uv), :he s;t of Boolean<br />
homomorphisms from U to the algebra Uvp = 2 . First, a ijec ion etween Horn<br />
(Urn, Uw) and uVU rasserted to exist. Then this bijection is used to transfer the<br />
Boolean structure whch uVpU has as an algebra of sets to Horn (Urn, U,). Let f be<br />
a function from U to Uw and let I be the function which maps each element of U to<br />
the corresponding principal ultrafilter. Because PUFU is a set of free generators for the<br />
Boolean algebra Urn, f o I-' extends uniquely to a homomorphism h: Um + UVP.<br />
Consequently, we can define a map M: Uw U<br />
+ Horn (%, UW) which carries f to<br />
the corresponding homomorphism h. This can be depicted as in figure 3.<br />
PUF,<br />
Figure 3<br />
i<br />
M is a function, because the extension of M is unique. M is an injection one-to-one),<br />
because if fi # % f1 0 I-' f f2 0 I-', and M(fi) and M(fi) extend fi 0 I and f2 0 I-<br />
l, respectively. Finally, M is a surjection (onto), because if k is in Horn (Urn, UVP), M(1<br />
i o k) = k, again because the extension is unique. Thus, M is a bijection between<br />
uWU and Horn (Urn, UVP).<br />
M can be used to define Boolean operations on Horn (UNP, UVP). That is to say:<br />
The notion of a free generator is discussed extensively in Sikorski (1969: 42-45) and Halmos (1963;<br />
4-46).<br />
\
(38) Definition<br />
It is easily established that Horn (UW, U*), with operations so defined, is a Boolean<br />
algebra. In practice, what this means IS that the result of applying negation, regarded as<br />
the operation of Boolean complementation, to a transitive verb is another transitive verb<br />
with the same homomorphic properties as the original one. Thus, an expression such as<br />
didn't see, analyzed as a negative transitive verb phrase, denotes a homomorphic, hence<br />
monotone increasing, function.<br />
7. Monotonicity analyses<br />
By means of the semantics just described, we can associate a sentence such as John<br />
didn't see some of the paintings with the categorial derivation in (39). It is easy to see<br />
that application of didn't to see gives us the monotone increasing (more precisely,<br />
homomorphic) transitive verb phrase didn't see. The next step in the derivation uses the<br />
operation of function composition to create the expression John didn't see.<br />
(39) John didn't see some of the paintings<br />
S/VP ((VP/NP)/(VP/NP)) VP/NP NP<br />
f G ?<br />
It should be clear that the noun phrase some of the paintings is the argument of a<br />
monotone increasing function - to wit, the Boolean homomorphism associated with the<br />
composite function John didn't see. This explains the validity of the conditional in (33).<br />
To understand the relationship between monotonicity properties and function<br />
composition, one does well to take the table in figure 4 into consideration.<br />
Figure 4
As an illustration of this monotonicity table, consider the categorial derivation in (40).<br />
Clearly, the negative transitive verb phrase didn't see is the result of composing the<br />
monotone decreasing function didn't and the monotone increasing function see.<br />
According to the table, this derived expression is monotone decreasing in nature. In a<br />
similar way, we can use composition to create the phrase John didn't see, which must<br />
also be regarded as a monotone decreasing expression.<br />
John didn't see some of the paintings<br />
VP/NP NP<br />
+ J, +<br />
It should now be clear that the expression some of the paintings in (40) occurs in a<br />
downward monotonic context. Hence, the validity of the conditional in (32). This brings<br />
our discussion of the relationship between various types of negation to an end.<br />
References<br />
Banvise, J. and R. Cooper (1981), 'Generalized Quantifiers and Natural Language.'<br />
Linguistics and Philosophy 4: '159-219.<br />
van Benthem, J. (1986). Essays in Logical Semantics. Dordrecht: Reidel.<br />
van Benthem, J. (1991). Language in Action: Categories, Lambdas and Dynamic Logic.<br />
Amsterdam: North-Holland.<br />
Brown, K. (1991). 'Double Modals in Hawick Scots.' In: P. Trudgill and J.K. Chambers<br />
(eds.) Dialects of English. London: Longman, 74-103.<br />
Frege, G. (1979). Posthumous Writings. Edited by H. Hermes, F. Karnbartel, and F.<br />
Kaulbach, with the assistance of G. Gabriel and W. Rodding. Translated by I?. Long<br />
and R. White, with the assistance of R. Hargreaves. Oxford: Basil Blackwell.<br />
Frege, G. (1980). Translations from the Philisophical Wn'tings of Gottlob Frege. Edited by<br />
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Halmos, P.R. (1963). Lectures on Boolean Algebras. Princeton, New Jersey: Van<br />
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