128
ANALYSIS
context-dependence that if things had been different, 'the actual
world' would have picked out some world other than the actual
one.
Tulane University,
© GRAEME FORBES 1983
New Orleans,
Louisiana 70118, U.S.A.
ACTUALITY AND CONTEXT DEPENDENCE II
I
I
N his paper, 'Does Tense Logic Rest Upon a Mistake?' (to appear
in a Festschrift for Donald Davidson, edited by Bruce Vermazen
and Merrill B. Hintikka), Gareth Evans considered three possible
semantic treatments of temporal modification. One he rejected as
involving an incoherent conception of assertion. The other two he
admitted as coherent; but in each case he argued that there are
important disanalogies between temporal modification and modality.
His conclusion was that tense logic should not be regarded as
genuinely analogous to modal logic: we should not be 'blinded by
the structural parallels between time and modality to their substantial
differences'.
In Meaning, Quantification, Necessity: Themes in Philosophical
Logic (Routledge and Kegan Paul, 1981; henceforth lMQN\
I stated the main points of Evans's argument. Graeme Forbes is
still not convinced ('Actuality and Context Dependence I', ANALYSIS,
this issue). In this note I shall try to make clearer what I take the
argument to be.
Of the two semantic accounts that Evans admitted as coherent,
one involves the claim that an expression, such as 'Whitlam is angry',
which admits significant temporal modification is strictly speaking
ambiguous. The other involves the claim that temporal modifiers
are context shifting operators. On the ambiguity account, 'Whitlam
is angry' is assigned quite different semantic values according as
it occurs standing alone or modified by a temporal operator. As it
occurs standing alone, the expression is a context dependent
sentence, and relative to any context it is assigned a semantic value
appropriate to a complete sentence. This value has to provide for
the evaluation of an utterance of the sentence in that context as
TRUE or FALSE once-for-all, where TRUTH is the primary dimension of assessment for utterances, the aim of sincere assertion. As
it occurs modified by a temporal operator the expression is assigned
Downloaded from analysis.oxfordjournals.org at Radcliffe Science Library, Bodleian Library on August 27, 2011
By MARTIN DAVIES
ACTUALITY AND CONTEXT DEPENDENCE II
129
II
We can distinguish two lines of thought which lead to the idea that
a 'semantically fastidious' representation of the context dependent
sentence 'Whitlam is angry' will involve the closure operator 'Now'.
First, the situation expression 'Whitlam is angry' admits significant
temporal modification because (even relative to a context) it
expresses a condition that obtains at some times and not at others.
But such a temporally relative condition cannot be the condition
for the TRUTH of an utterance of 'Whitlam is angry' standing
alone, since assessment for TRUTH is a once-for-all matter. To
obtain an expression which expresses (relative to a context) a condition that can be a TRUTH condition we need to apply the closure
operator to the situation expression.
Second, if our theory provides only for the temporally relative
condition, then we are left asking the question 'What should [a
sincere asserter] aim at?'. The answer, of course, is that as the
language is actually used he should aim at producing an expression
whose temporally relative condition obtains at the time of utterance. But in that case the expression uttered should be represented
as involving reference to the time of utterance. Other conventions
of use are possible, and if the convention were different then the
representation would have to be correspondingly different.
It may seem that this is a distinction without a difference, but
in fact the difference becomes clear when we turn to modality. If
an expression is to admit significant modal modification it needs
to be contingent. We can avoid potentially confusing complications
if we choose an expression which is free of temporal or spatial
relativity. So let us take as our example 'Snow is white', construed
Downloaded from analysis.oxfordjournals.org at Radcliffe Science Library, Bodleian Library on August 27, 2011
(even relative to a context) a quite different semantic value, akin to
that of a predicate of times. If we are 'semantically fastidious' then
we should remove this ambiguity by distinguishing between what
Evans called a situation expression (akin to a predicate of times)
and the context dependent sentence which can be represented as
the result of applying the closure operator 'Now' to the situation
expression.
On the context shifting account, on the other hand, the expression 'Whitlam is angry' is a context dependent sentence in all its
occurrences. But the semantic value assigned to a temporally
modified sentence relative to a given context is not a function of
the semantic value of the contained sentence relative to that same
context; it depends upon the semantic value of the contained
sentence relative to other contexts.
I shall consider the two accounts in turn (following Evans, and
reversing the order of presentation in MQN).
130
ANALYSISI
Ill
My view about the location in the conceptual order of the notion
of a possible world is similar to that expressed by Colin McGinn:
'if we are limning the true and ultimate structure of modal reality,
we do better to leave the modal connectives primitive: paraphrasing
them with possible worlds quantifiers misrepresents how things
modally are'. ('Modal Reality', in Richard Healey (ed.), Reduction,
Time and Reality, Cambridge University Press, 1981, p. 162.)
Downloaded from analysis.oxfordjournals.org at Radcliffe Science Library, Bodleian Library on August 27, 2011
as expressing a condition which obtains only contingently but is
not temporally or spatially relative.
Since 'Snow is white' already expresses a condition that can be
the condition for absolute or once-for-all TRUTH of an utterance,
we have nothing corresponding to the first line of thought. But it
can seem plausible that there is, analogous to the second line of
thought above, an argument for the idea that a 'semantically
fastidious' representation of 'Snow is white' standing alone will
involve the 'Actually' operator (which is formally analogous to the
'Now' operator).
The conventions of use of our language could have been such
that an utterance of 'Snow is white' is TRUE iff the expressed
condition would have obtained (even) if kangaroos had no tails.
In that case the representation of the expression would have
involved a counterfactual conditional. As the language is actually
used, the utterance is TRUE iff the expressed condition obtains
as things actually are. But in that case should not the expression
uttered be represented as involving reference to the actual world?
If this argument is a good one then we shall have to agree that no
deep disanalogy between the temporal and modal cases has been
demonstrated.
The main claim that Forbes makes is that a deep disanalogy
cannot be demonstrated without appeal to metaphysical differences
between times and possible worlds. I believe that Evans would have
agreed. At one point he wrote: 'A sane view of possible worlds
begins when we conceive of the actual world as the world in which
all and only true propositions are true'. In MQN, I said essentially
the same in reply to the argument set out in the last paragraph.
(MQN p. 209. Christopher Peacocke drew the argument to my
attention.) Forbes objects that the familiar rubric about truth
reveals that notion as not conceptually prior to the notion of the
actual world (Forbes p. 126). A short reply to that objection is
that, as it occurs in the familiar rubric, the expression 'the world'
does not refer to the actual world conceived as a member of a set
of possible worlds. A more formal version of the rubric makes this
clear: if _s can be used to assert that p, then s is true iff p. (Cf.
MQN p.f27.) In the next section, I shall set out a little more fully
what I take the order of conceptual priority to be.
ACTUALITY AND CONTEXT DEPENDENCE D
131
IV
Let us turn to the question whether the temporal and modal cases
can be seen as analogous if temporal modifiers are treated as context
shifting operators. It might seem that the cases can be seen as
analogous: 'we can just take possible worlds to constitute the contexts' (Forbes p. 124). But then, of course, we face the question
whether we can think of worlds as contexts, and Forbes gives a
reason for saying that we cannot: 'The significant difference . . . is
that we move through time and from place to place, but we do not
Downloaded from analysis.oxfordjournals.org at Radcliffe Science Library, Bodleian Library on August 27, 2011
Given the ideas of a sentence with a truth condition and of
assertion as aiming at truth, we can employ the notion of possibility
(expressed by the modal operator) to arrive at the idea of a condition
which does not obtain but might have obtained, and with it the idea
of a sentence which is not true but might have been true. Given also
the notion of conjunction, we can arrive at the idea that various
conditions might have obtained, and corresponding sentences been
true, together. Here we have the idea of a possibility (or a way
things might have been, or even a way 'the world' might have been).
The notion of a possible world is an idealisation of this notion of
a possibility: a possible world is the limit of a process of refinement
of possibilities. (See Lloyd Humberstone, 'From Worlds to Possibilities', Journal of Philosophical Logic 10 (1981), and Graeme Forbes,
'Physicalism, Instrumentalism and the Semantics of Modal Logic',
forthcoming in Journal of Philosophical Logic.)
Possibilities and possible worlds are, on this conception, abstract
objects rather like sets of propositions. We can think of possibilities
and possible worlds as regions and points in 'logical space', but
there are clear ontological differences between these 'regions' and
'points' and intervals and moments of time, or regions and points in
physical space. (See McGinn op cit. pp. 151-2.)
Thus we arrive at the idea of a collection W of possible worlds,
and the idea of sentences being true or false relative to a member
w of W. Amongst the possible worlds in W, one can be distinguished
as the actual world: it is that world w such that the sentences that
are true relative to w are precisely the sentences that are true
(simpliciter). This is the conception of the actual world which,
according to Evans, is needed for 'a sane view of possible worlds'.
If what I have just sketched is a sane view of possible worlds
then, clearly, a proper conception of assertion and truth does not
require the use of 'Actually' as a closure operator. For to say that
in assertion one aims at truth relative to the actual world is to say
no more about assertion than that one aims at truth.
It should be clear that, in offering these reflections, I am not
disagreeing with Forbes's main claim. For whether or not they are
taken in an eliminativist spirit, these reflections are metaphysical
rather than semantic.
132
ANALYSIS
Downloaded from analysis.oxfordjournals.org at Radcliffe Science Library, Bodleian Library on August 27, 2011
move through the other possible worlds in which we exist' (p. 127).
I think that Forbes is essentially right about this. I myself would
try to highlight the significant difference by considering two facts
about context dependent reference (e.g. the use of 'now' or 'here')
in contrast to the use of 'actually'.
First, in context dependent reference the object referred to
(e.g. a time or a place) is a member of an extensive class (of times
or places). If we say that in a use of 'actually' there is reference to
the world in the sense of 'I and all my surroundings', then we have
a sharp contrast with this first fact. We avoid that contrast if we say
that in a use of 'actually' there is reference to the actual world that
is a member of the set W.
But, second, in context dependent reference there is an appropriate relation — an en rapport (causal) relation or a locational
relation — between the token thought event (or token utterance)
and the object referred to. On my conception, the members of
W are abstract objects rather like sets of propositions, and we stand
in no causal relations — and so no en rapport relations — to them.
Nor can reference to a member of W be secured by the obtaining
of a locational relation. For a token thought event or token utterance is located in countless different members of W.
Perhaps we can find something analogous, in the case of abstract
objects, to an en rapport relation to a physical object. This is
a difficult matter, but in the case of a set I think that the closest
analogue is having exhaustive knowledge of the membership of the
set. (See MQN pp. 110-11.) In the case of a possible world, the
closest analogue would then seem to be having exhaustive knowledge of the conditions that obtain at the world. But that is knowledge that we do not have, even for the actual world. (Hence the
remark at MQN p. 206, quoted by Forbes at (a) on p. 124.)
If a speaker uses 'now' or 'here' (or 'I' or 'you') in an utterance,
then it is not sufficient for understanding of that utterance that
an audience should merely know the meaning of the sentence
uttered. He must be able to identify the time or place (or speaker
or addressee) of the context of utterance; only then will he know
what has been said. In central cases, this identification involves the
audience thinking of the time or place (or person) under a demonstrative, rather than a merely descriptive, mode of presentation;
and this is possible precisely because the audience stands in an
appropriate en rapport or locational relation to the object. But
one can hardly hold that understanding of an utterance involving
'actually' requires identification of the actual world from amongst
the set W of possible worlds.
These reflections, like those of the previous section, are of a metaphysical, rather than a purely semantic, character. So again, they
involve no disagreement with Forbes's main claim. Nor, I think,
would Evans have disagreed. Concerning the application of a context shifting account to modality he wrote: 'To think in this way
ACTUALITY AND CONTEXT DEPENDENCE II
133
about possible worlds seems to commit one to an unacceptable
form of modal realism'.
It seems then that on neither the ambiguity account nor the
context shifting account of temporal modification is it genuinely
analogous to modality.1
Birkbeck College,
Malet Street,
London WC1E 7HX
1
©MARTIN DAVIES
1983
I am grateful to Graeme Forbes and Christopher Peacocke for advice on this note.
By ALAN R. WHITE
A RECENT attempt in this journal (R. A. Sorensen, 'Knowing,
l\Believing
and Guessing', ANALYSIS 42.4, October 1982, pp.
212-3) to support the thesis that knowing that p implies believing
that p is based on the supposition that if one wrongly believes that
one's method of arriving at an answer is unreliable, then one does
not know the answer (Sorensen says 'Julia did not know the answers
to the examination since she was mistaken about [Sorensen means
that she had a wrong view about] the reliability of the method'
and 'Since Jean falsely believes that his method is unreliable, Jean
does not know the correct answer to the English history questions').
But this supposition is really a variant on the thesis at issue and so
begs the question. Moreover, the supposition is as wrong, and for
the same reasons, as the thesis.
Seeds of doubt about the reliability of his method may exist or be
sown in the mind of one who uses a reliable method to arrive at an
answer as easily, and in the same way, as seeds of doubt may exist
or be sown about his knowledge of the answer in the mind of one
who knows the answer. If someone is wrongly persuaded by a mathematician that his method of telling at a glance whether a large
number, other than one ending in zero, is divisible by four, namely
by checking whether the number represented by the last two digits
is divisible by four, is mistaken, does he not know that, e.g. the
number 1234567896 is divisible by four? If a physicist succeeds in
making someone wrongly distrust the reliability of telescopes, does
he not know that the distant object seen through his telescope is
a building? If a sceptical philosopher's subtle arguments entice
someone into falsely believing that sense perception is never a
reliable method of discovering material objects, does he never know
Downloaded from analysis.oxfordjournals.org at Radcliffe Science Library, Bodleian Library on August 27, 2011
DOUBTING ONE'S METHODS