The World
of the uncountable:
ontology
and the mathematicisation of logic
Henry Laycock
The
mathematicisation of logic represented especially by Frege – and subsequently
by Russell, Wittgenstein, Tarski and others – has become a key instrument
within analytical philosophy, invoked in the treatment of a great variety of
problems and issues. No domain better illustrates this fact than contemporary
ontology itself. As Quine quite rightly emphasizes, the ontic scope of modern
logic is effectively defined by the bond between ontology and the variable :
‘Existence’, he declares, ‘is what existential quantification expresses’. There
are however major problems with the ontic application of this formal framework;
and it is possible to see these problems as turning on the logico-semantic
status of the class of so-called mass nouns. What Davidson once called
‘the problem of mass nouns’ is, indeed, a specific problem with this framework.
What is distinctive about the semantics and ontology of mass nouns – that is, in
effect, the semantics and ontology of words for stuff – is that they
cannot be understood in terms of countability or units, and cannot
thereby be represented in a logic of quantifiers and variables. Contrary, then, to Quine, existence is
not what existential quantification expresses. The issue is essentially
a formal one, and concerns not only mass nouns in particular, but is no less an
issue over count nouns and the formal representation of commonplace, everyday
talk of objects. The two issues are virtually inseparable, and I treat them
here as such.
Now the
work of the linguist Otto Jespersen remains substantially neglected by
philosophers. Yet his writings on what he calls
‘mass-words’ and ‘thing words’ – he also speaks of ‘uncountables’ and ‘countables’
– contain deeply insightful observations on matters of great interest; and not
only for semantics, but even more, perhaps, for metaphysics. Jespersen
contrasts thing words with mass-words, speaking of the latter group as words
for substances. Jespersen writes
There are a
great many words which do not call up the idea of some definite thing with a
certain shape or precise limits. I call these ‘mass-words’; they may be ...
material, in which case they denote some substance in itself independent of form,
such as silver, quicksilver, water, butter, gas, air, etc.
Elsewhere,
Jespersen also suggests a far-reaching logico-semantic contrast between
thing words and mass-words, forcefully asserting that
Mass-words
are totally different, logically they are neither singular nor plural, because
what they stand for is not countable.
And in this
same spirit, Jespersen speaks of the need for an ideal language
‘constructed on purely logical principles’, and tells us that a distinctive
logical form would be called for
when we
left the world of countables (such as houses, horses, days, miles, sounds,
words, crimes, plans, mistakes, etc.) and got to the world of uncountables.
As it
happens, of course, just such an ideal language had been conceived some fifty
years earlier, although Jespersen himself seems to have been unaware of this.
At the same time, given its origins as a system for speaking of the (eminently
countable) realm of numbers, the question must be faced of the
appropriateness of the symbolism of Frege’s Begriffsschrift (‘modelled
upon that of arithmetic, for pure thought’) to the logical forms here at issue.
In what follows, I attempt to explain the significance of Jespersen’s remarks;
I also urge that what he says is true. If Jespersen is right, then indeed the semantics and ontology of words for
stuff cannot be understood in terms of units; and this itself implies, so I
claim, that the ontology of stuff can only be conceived as indeterminate.
1. Why Jespersen was right about ‘mass
words’.
It is commonly
remarked – by linguists and philosophers alike – that ‘mass nouns lack a plural
form’, or ‘do not pluralize’. As mere comments on English syntax, such remarks
are unobjectionable: it is perfectly obvious that in the usage of native
speakers, then unless the contest is generic, words like ‘sugar’, ‘gold’ and
‘water’ resist the plurality morpheme ‘-s’. Typically, however, such remarks
are bearers of a deeper meaning – not altogether unreasonably, they are thought
to mean that mass nouns cannot but be singular, and that in a semantic sense.
The view has very considerable ontic significance: it implies that references
involving concrete mass nouns must be understood as references to units,
discrete instances of stuff. And at first blush, this too may seem eminently
reasonable: given two glasses of water, we may distinguish the water in the one
glass, this water, from the water in the other, that water. How
then could this water fail to be one instance of the kind or concept water,
and that water another?
But now
while it is true that in non-generic contexts, grammar rules out plural talk of
‘waters’, it does not immediately follow that mass nouns are singular.
Consider, for example, the obvious fact that concrete singular constructions,
e.g. ‘a water’, are also counted out. Furthermore, mass nouns reject the
quantifiers appropriate to singular contexts, words like ‘each’ and
‘every’. Again, it is strikingly evident (and even commonly remarked) that in
the quantifiers they do accept, mass nouns more closely resemble plural nouns.
Parallel with ‘all apples’, ‘some apples’, ‘more apples’ and ‘most apples’ are
the phrases ‘all water’, ‘some water’, ‘more water’ and ‘most water’. In the
standard semantic model for mass nouns, these phenomena appear to be treated as
syntactical anomalies, yet a quite straightforward explanation is available,
and my initial aim is just to briefly lay it out. From the premise that ‘mass nouns do
not pluralize’ to the conclusion that they are (invariably) singular, there is
a key implied assumption – that all occurrences of nouns are semantically either
singular or plural. The assumption, I suggest, is simply false; and once
abandoned, the otherwise anomalous behaviour of mass nouns becomes manifestly
intelligible.
Mass nouns
are, indeed, standardly contrasted with count nouns or CNs; and the very
contrast of these groups implies that mass nouns must be among the class of
nouns which are non-count – non-count nouns, or NCNs. But now
occurrences of CNs are themselves semantically either singular or plural; and
these two sub-categories exhaust the general category of CNs. Qua
non-count, therefore, it seems that, as Jespersen claimed, mass nouns can be neither
singular nor plural; and given this, the basic shape of the
relationships between these groups can be neatly represented in the following
tableau:
Table I
|
1.
Singular (one)
|
2.
Non-singular
(‘not
one’)
|
3.
Plural
(‘at least one’)
|
|
‘Objects’
|
4.
Non-plural
(‘not at least one’)
|
‘Object’
|
‘Stuff’
|
On the bold
assumption, then, that the tableau has it right, it will be simply incorrect to
talk about the contrast between mass and count nouns, as if there were
just one – and furthermore, one which defined the entire relationship between
the categories. In fact, in anything other than purely morphosyntactic terms,
speaking as if a contrast is what matters is profoundly misleading.
Quite apart from the point that there is not just one but three contrasts
on display between these nouns or their occurrences, corresponding to the three
occurrences themselves, the fact is that, quite crucially, the semantic commonalities
between the groups are no less fundamental than the differences. Mass nouns share with singular count
nouns the feature of non-plurality, and share with plural count nouns the
feature of non-singularity. Fundamental to the difference between the two, on
the other hand, is the presence or the absence of a numerical unit:
because ‘water’ is non-singular, there is no single water-unit. In the
very nature of the case, water has no units, and there is no such object
as ‘a water’.
But why, it
may be asked, are the referential determiners and verbs for mass nouns
morphologically indistinguishable from semantically singular expressions?
Why should ‘this water’ look exactly like ‘this apple’? As Leech notes, syntax
‘is much less rich in dimensions of contrast than is semantics’, and the point
is illustrated in this morphosyntactic parallel. There are three semantic categories
here (singular, plural, and non-count) but the syntax of English
demonstratives can only take two forms, and to understand their taxonomy, we
need a bifold contrast merely of the plural and non-plural – a class
encompassing the singular along with the non-count. Since ‘water’ is itself non-plural
– but not thereby semantically singular – the water in a glass can only
be referred to as ‘this water’. Quantificational differences are marked in
English, but the syntax marks no contrast, in referential contexts, between
singular and non-plural – potentially thereby inviting a conflation of the two.
Now Table I
can be expanded to incorporate the appropriate verbs and determiners, including
definite and indefinite articles and quantifiers, thereby summing up the main
syntactic and semantic points thus far. The resulting table provides, I
suggest, a coherent, unified account of a number of key semantic features of
both CNs and MNs, along with a graphic display of their relationships:
Table II
|
SINGULAR
|
NON-SINGULAR
|
Reference-determiners
(definite articles) and verbs
|
PLURAL
|
|
apples
|
these / are
|
NON-PLURAL
|
apple
|
water
|
this/is
|
Quantity-determiners
(quantifiers, indefinite articles)
|
a,
an, each, every, any
|
some, all, any, most, more, many/much
|
|
The table
introduces an additional column, and a corresponding row, for the semantical
taxonomy of a wide range of determiners. Specifically, the table displays the
essentially orthogonal character of the relationship between the two
types of determiners – reference and quantification are seen to be orthogonal –
along with their matching functional differences. Quantifiers bear on the
singular / non-singular distinction, while demonstratives and other referential
determiners bear on the plural / non-plural distinction. The standard semantic
model for MNs as singular object-designating expressions, on the other hand,
offers no explanation whatsoever for this interrelated set of phenomena.
Consider
now the existential significance of the orthogonal relationships between what I
am calling reference-determiners and quantity-determiners. As the existence of
apples consists first and foremost in that of individual apples, this apple
or that apple, so, it might seem, the existence of water consists in the
existence of amounts of water, this water or that water – not,
indeed, of a water like an apple, but rather of some water,
a certain determinate amount of water, much as some apples constitute a
certain determinate number of apples. And, whether this conforms to Quine’s principle
that to be is to be the value of a variable or not, it seems to be consistent
with the spirit of that principle. The idea is that at the very least, to be is
to be determinate – in the case of concrete material beings, concrete
things or stuff, to be (as Aristotle also said) is to be this or that
– this apple or that water, the potential subject of an
identity-involving reference.
2. Existence, determinacy, neutrality.
But now
although Table II displays certain relationships between mass and count nouns
and determiners, there is no suggestion that the use of these nouns requires
the use of determiners. In English, concrete singular occurrences of nouns
do (almost) always take determiners – either the so-called definite or
indefinite article, or a singular quantifier. But in their plural (and more
generally, non-singular) occurrences, nouns do not always take determiners; and
this, I suggest, is a reflection of the fact that whereas the use of a singular
noun is intrinsically or essentially determinate, the use of a plural or
non-singular noun is not. The difference is semantically of great importance,
and is manifest in the contrasting ways of describing the kinds or sorts
to which the subjects belong. To the question of what a strange-looking
piece of fruit on the table is, the full and complete answer could well
be that it is an apple, and perhaps, a certain variety of apple –
the point being that here, in the English singular, an (indefinite) article is
required. If on the other hand there is more than one of the fruit, then the
answer to the question of what they are will be just that they are apples;
no article now required.
The use of
the plural determiner ‘some’ in this context – ‘some apples’ – carries numerical
information, to the effect that there is more than one; used with a CN,
‘some’ can typically be paraphrased as ‘a number of’. But here however, the determiner
contributes nothing to answering the question of what they are. The
plural (and more generally, non-singular) description of the appropriate kind
or category involves no use of a determiner. Again, much as there can be some
apples on the table, there can also, of course, be some water on the table; but
the answer to the question of what there is on the table – what kinds
of things and stuff there are on the table – is that on the one hand there
are apples, things of the apple-kind, and on the other hand there is water,
stuff of the water-kind. That there is a certain determinate amount of water on
the table might perhaps go without saying; but it contributes nothing to
answering the question of what the stuff on the table is.
The general
point is recognised, if only tacitly, by Quine, who tells us that
We commit
ourselves outright to an ontology containing numbers when we say there are
prime numbers between 1000 and1010; we commit ourselves to an ontology
containing centaurs when we say there are centaurs.
Here,
appropriately, there is no use of the plural determiner ‘some’, no question of
determinacy as to numbers. Conceived a la Quine, the role of the existential
quantifier is quite precise. It is not that of a device for making just any
kind of existential statement; its assigned role is that of an ontic device
– a device essentially for giving existential information regarding
categories and kinds of things, quite simply that. Having pronounced that
what ‘thus confronts us as a scheme for systems of the world is that structure
so well understood by present day logicians, the logic of quantification or
calculus of predicates’, Quine adds
The
doctrine is that all traits of reality worthy of the name can be set down in an
idiom of this austere form if in any idiom. It is in spirit a philosophical
doctrine of categories.
In its
ontic role, ironically, the quantifier is no device for providing information
on quantity, on the numbers of the members of the diverse
categories and kinds – on the number of pigeons, galaxies, or concrete objects
there might be. What matters, from the ontic standpoint, is purely and simply
whether there are things of this or that kind or not. Quine’s
declaration that existence is what existential quantification expresses is
followed by a bare plural form of
remark, ‘There are things of kind F if and only if (∃x)(Fx)’.
For this
reason, what the operator ∃ actually represents is quantification
in name only – precisely because its role is to be numerically neutral. There
is a difference between the existential quantifier, so to say, and
so-called numerical quantification, as in ‘There are at least five
rabbits in the garden’, ‘There are exactly two prime numbers between 1 and 4’,
and so on. The bare plural form is the
quantitatively neutral use of the quantifier, and as Quine’s remarks nicely
illustrate, this is the precise way of expressing numerical neutrality
in natural English.
Cast in
symbolic, formal terms, the operator tells us that there is at least one thing
of such and such a kind – a numerically neutral form of statement, plainly –
and the use of the bare plural is the uniquely appropriate
natural-language mode for the expression of this fact. The role of numerical
quantifiers is indeed in the proper sense to quantify – to specify
numbers, whether definitely or indefinitely – whereas pace Quine, the role
of the existential quantifier is merely to assert existence. On the one
hand, there is the purely taxonomic, kind- or category-specifying form of
information; on the other, there is information with an empirically
quantitative form. But thanks in part to the misleading terminology of quantification
– the fact that what is called ‘the existential quantifier’ is so
called – this numerical irrelevance or quantitative neutrality is not always
clearly understood.
But now,
there is a certain tension in Quine’s formulation here, that there are things
of kind F if and only if (∃x)(Fx). There can be no objection to
the bare plural formulation, ‘there are things of kind F’; however, it
is not well-matched to the other half, the formal portion of the
statement. The problem lies in the
unwarranted assumption that ‘there are Fs’ can be paraphrased as ‘there is at
least one F’, which has, among other things, an indirectly referential
character, whereas the use of the bare plural, as such, does not. Ontological
assertions, in Quine’s sense and mine, are quantitatively neutral; and
that is certainly the principle underlying the existential quantifier,
conceived as an ontic operator or device. However, for existence to be
expressed by the existential quantifier, severe restrictions must be imposed on
what in general can be said to exist; Quine’s principle is not a general truth.
It must be possible to recast the sentence in an indirectly referential form –
a form, that is, that requires the possibility of reference to something of
what is said to be. And this can only be done in a way that preserves
the neutrality of the original sentence where the predicate at issue is
distributively singular in a strong sense. The problem lies in the
potential mismatch of the semantically singular variable (a familiar feature of
the standard first-order predicate calculus) with the semantically unrestricted
character of the predicate. The trouble is that the informal half of the
statement only counts as quantified in virtue of its equivalence with the
formal half; and this latter portion itself only works for a certain highly
restricted range of predicates – ones which are distributively singular in
a strong sense. And if we attempt to broaden the scope, to produce a
comprehensive form of sentence, we find that our sentences can no longer be
quantified (into the form of ‘there is something such that F’) or are no longer
indirectly referential, and must be understood semantically as
indeterminate. In effect, they become sentences without logical subjects – and
that is precisely what many ontic assertions involving bare mass nouns are like
.
Many common
count noun predicates call for there to be more than one object of which they
are true. For example, where ‘F’ = ‘family member’, ‘classmate’, ‘piece of
gravel’, or ‘member of the team’, there is nothing wrong with a sentence having
the form ‘There are things of kind F’ – ‘There are classmates, family members,
pieces of gravel, members of the team, and so forth’; but no things of these
kinds can live a logically solitary existence. In one good sense, even though
they are true of each member of the corresponding kind, the predicates are
essentially collective. For predicates of this type, ‘There is exactly one F’
and ‘There is at least one F’ are not well-formed formulae. For there to be
classmates, there must be some of them. Nevertheless, the role of the
plural determiner ‘some’ is to carry numerical information to the effect that
there is more than one, which in this case goes without saying (and applied
across the board, would be incorrect; in most cases, it is not necessary for
there to be more than one F). Used with a CN, ‘some’ can typically be
paraphrased as ‘a number of’, but it contributes nothing to answering the
question of what they are. Here, if existential quantification involves
the assertion of ‘at least one’, then existence is not what existential
quantification expresses. There must be at least two; but this is non-neutral,
and does not go into the expression of existence.
But the
problem is more serious than this. Quantification requires that there be (real
and not just grammatical) subjects for the predicates; the point goes back to
Frege. This, functions require arguments; whereas concepts do not, it
seems, need objects. In one respect,, the problem is latent even with the use
of distributive predicates: the contrast of a pair of bare sentence and
non-bare sentences will illustrate the point. Contrast
(Q) Some
dogs have been barking all night
with
(B1) Dogs
have been barking all night.
Whereas (Q)
implies that the same dogs have been barking all night, (B) does not. (Q) is determinate, whereas (B) is not.
There is nothing of which the predicate in (B) need be true; it is
enough if, at any time during the night, at least one dog was barking. Here,
then, a certain reduction is possible. But when a collective predicate becomes
involved, as with
(B2) Classmates have been partying
upstairs all evening,
neither
singular reduction nor plural is possible. The singular is of course ruled out
by the collective nature of the predicates; and the plural is ruled out by the
fact that there is no requirement that at least two classmates were partying
upstairs all evening; there might be a constant rotation. A reduction is
nevertheless still possible; it must be the case that at any time during the
evening, at least two classmates were partying. But finally, mass nouns can be
used in a cognate statements involving temporally extended and essentially
unbounded episodes, truth values must be assigned to sentences relative to intervals
of time, rather than to points in time or moments, thus:
Oil is
pouring over the barriers,
Cheap
imported furniture flooded into the domestic market,
Smoke is
billowing from the chimneys,
Mud is
oozing through the wall.
And here,
the subjects of the predicates cannot be open to identity-involving
reductions, since pace Heraclitus, the process-predications themselves
demand continuous change.
( Draft - texte de la conférence prononcée par l'auteur le 21 Janvier à Aix-en-Provence )
Quine might here – just – be counted as
an exception.
The Philosophy of Grammar, p.198.
‘On What There Is’, Willard V. Quine,
The Review of Metaphysics , Vol. 2, No. 5 (Sep., 1948), pp. 21-38; p. 28.