I recently posted an account of necessity de dicto. The purpose of this post is to pin down exactly what this topic is. The
notion in question of course looms large in contemporary analytic
philosophy, but it will serve us well and keep us grounded to
furnish in as clear a way as possible a basic
characterization of it. In a future post, I will turn to specifying the problem or task which my account is addressed to with respect to the topic. In another future post, I will
state some of my assumptions and guiding ideas.
The key source for the notion of necessity de dicto is of
course Kripke's Naming and Necessity. It was there that our
topic was (to the best of my knowledge) first clearly isolated and
characterized. Priority aside, Kripke's characterization is not
easily improved upon and has been very influential. (Regarding the
notion itself, not its characterization: it is a very interesting
historical question to what extent this notion was present in earlier
thinking. Or to what extent similar notions were, and how they may
relate to the present notion. I will make no attempt here to answer
this.)
Kripke's starting-point in characterizing the notion of necessity de
dicto is to remark that, while many (at the time he was speaking)
seem not to differentiate between a priority and necessity, he
certainly will not use 'a priori' and 'necessary' in
the same way (p. 34). He then, after emphasizing that the notion of a
priority is an epistemological one and mentioning some issues which
might arise with that notion, gives the following characterisation of
necessity:
The
second concept which is in question is that of necessity. Sometimes
this is used in an epistemological way and might then just mean a
priori. And
of course, sometimes it is used in a physical way when people
distinguish between physical and logical necessity. But what I am
concerned with here is a notion which is not a notion of epistemology
but of metaphysics in some (I hope) nonpejorative sense. We ask
whether something might have been true, or might have been false.
Well, if something is false, it's obviously not necessarily true. If
it is true, might it have been otherwise? Is it possible that, in
this respect, the world should have been different from the way it
is? If the answer is 'no', then this fact about the world is a
necessary one. If the answer is 'yes', then this fact about the world
is a contingent one. (pp. 35 – 36.)
This
should go a long way to giving us an acceptable grasp of the notion
of necessity de
dicto.
Kripke also says some things about the extension
of the notion which may be of further help to this end. Before
proceeding to that, however, I want to tighten up Kripke's
characterization in a couple of ways, as well as emphasizing and
de-emphasizing certain parts of it.
For
one thing, note that Kripke moves freely here between talking of
'facts about the world' as well as things which can be called true or
false, as the bearers of necessity. Later, he speaks also of 'states
of affairs' and 'statements'. This is fine, but I want to make it
clear that the topic I am addressing in my account is the notion of necessity as it
applies to things which can be called true or false: statements –
or as I say, propositions. This is what I mean by 'de
dicto'
in 'necessity de
dicto'.
To be still more precise about what propositions are – for a start,
whether they are or involve sentences themselves, or just their
meanings – is not necessary, but see this post for an approach I favour.
(At
this point I should emphasize that that is all
I mean by 'de
dicto'
in 'necessity de
dicto'.
The term 'de
dicto',
and the contrasting term 'de
re',
are used in various ways in philosophy. It it especially important to
realize that I count all attributions of necessity to propositions as
attributions of necessity de
dicto,
even when those propositions are “singular propositions” about
individuals – i.e., propositions attributions of necessity to which
David Lewis would deploy counterpart theory to understand.)
Something
I want to emphasize in Kripke's characterization is the way it cashes
out necessity in terms of counterfactual
scenarios – to use the language of some two-dimensional
semanticists, scenarios considered
as counterfactual,
rather than scenarios considered
as actual.
This could be emphasized by calling our topic 'counterfactual
necessity de
dicto'
or 'subjunctive necessity
dicto',
but I avoid this for the sake of brevity.
(You
may think that this is the same as the point that necessity is not to
be understood epistemologically, but I'm not so sure. For one thing,
I suspect there are notions of 'could actually be the case' and 'must
actually be the case' which, even if 'a
priori possible'
and 'a priori
true'
may be good expressions for them, can be cashed out
non-epistemologically. (Cf. this post.) For another thing, 'Could have
been' talk can also be given an epistemological reading, along the
lines of 'Was epistemically possible'. In any case, emphasizing that
with the notion of necessity de
dicto
we are dealing with scenarios considered
as counterfactual,
can only help to avoid misunderstanding here.)
Something
I want de-emphasize in Kripke's characterization, on the other hand,
is the way he classifies
the notion of necessity he wants to talk about as a notion belonging
to metaphysics. I do not think this is essential to grasping the
notion in question: that can be done without any recourse to a notion
of metaphysics. Kripke's use of a category of metaphysics here may be
slightly helpful in emphasizing that necessity de
dicto is
not an epistemological notion, but that point can be emphasized
without a notion of metaphysics. Since we can easily get by here
without invoking a notion of metaphysics, I think we ought to avoid
doing so. I am not going to argue the point at length here, but I
suspect that invoking a notion of metaphysics may lead to some
unhelpful prejudice about how the notion is best to be understood and
analyzed (if it is
to
be analyzed) – or more to the point, how it is not
to be analyzed. In particular, I worry that it may cause prejudice
against accounts which crucially involve semantic considerations, by
promoting a vague idea that necessity de
dicto
is “all about” how things are in the world, as opposed to having
anything to do with language and thought.
Finally,
Kripke's characterization should be supplemented with something about
the sense of 'necessary' being unrestricted
or very broad. To see this, consider an utterance like 'It is true
that I stayed home yesterday. This couldn't have been otherwise, as I
had to be there to let the electrician in.' This utterance may be
true, but in that case the 'couldn't have been otherwise' part is not
about necessity de
dicto
in the sense I am interested in – we are dealing with a
contextually restricted range of ways things could have been. For
instance, we are probably ignoring ways things could have been in
which I stop caring about having electricity, or in which I never
made the appointment with the electrician, or in which the
appointment was on a different day. This supplementation of the
Kripkean characterization has become customary. Witness Timothy
Williamson in an interview:
Something is metaphysically necessary if it couldn’t have been
otherwise, in the most unrestricted sense. (Williamson & Antonsen
2010, p. 18.)
Or Daniel Stoljar, referring to:
(…) the completely unrestricted sense of possibility that
philosophers sometimes call “logical” or “metaphysical”
possibility (…) (Stoljar 2006, p. 34.)
Or this terminological stipulation made by van Invagen:
Modal terms will be used in their “metaphysical” or
“unrestricted” sense (…). (van Invagen 2015, p. 35.)
There is a wrinkle here, however. For some things philosophers say
may seem to go against the propriety of characterizing our topic in
this way. On the way of speaking I have in mind, there are
necessities in the sense of our topic which are not necessary in some
other sense – 'logically' or 'mathematically' or 'epistemically'
for example. See, for instance, this passage in Nathan Salmon (where
he is arguing that an objection made to something he has proposed – the details of which don't matter here – does not hold water):
Metaphysical modality is definitely not an unrestricted limiting case. There are more modalities in Plato’s heaven than are dreamt of in my critics’ philosophy, and some of these are even less restrictive than metaphysical modality. One less restrictive type of modality is provided by mathematical necessity and mathematical possibility. […] Another type of modality less restrictive than metaphysical modality is provided by what is sometimes called ‘logical necessity’ and ‘logical possibility,’ to be distinguished from genuinely metaphysical necessity and possibility, or necessity and possibility tout court. A proposition is logically necessary if its truth is required on logical grounds alone […]. Although there is a way things logically could be according to which I am a credit card account, there is no way things metaphysically might have been according to which I am a credit card account. (Salmon 2005, p. 136)
But notice the contrast at the end of this passage between 'could be' and 'might have been'. Salmon is concerned here with what he calls 'the confusion between the generic notion of a way for things to be and the modal notion of a way things might have been'. According to Salmon, this confusion
is very probably the primary source of the idea that metaphysical modality is the limiting case of restricted modalities, that metaphysical necessity and possibility is the unrestricted, and hence the least restricted, type of necessity and possibility. For metaphysical necessity is indeed truth in all ways things might have been (modal, not generic), and metaphysical possibility is indeed truth in at least one way things might have been (modal, not generic). (ibid, p. 136.)
So, since we are explicitly talking about ways things might have been, it seems that Salmon would have no real disagreement after all with Williamson's succinct characterization of our topic, quoted above (except perhaps for some pragmatic disagreement about what to emphasize, or how best to use language to avoid potential confusions).
In any case, one thing that should be clear is that we are not dealing with a notion where certain contextually relevant matters of fact may be held fixed, as in the electrician example above.
So much for the intensional characterization of the notion of necessity
de dicto.
Another thing which may help us grasp the notion is consideration of
its extension – cases, and what types of cases there are. Most
instructive in this way are cases lying outside the overlap of
necessity and a priority. After giving his intensional
characterization of the notion, Kripke goes on to say that he will be
arguing that, in addition to being conceptually different, the
categories of necessity and a priority are extensionally different:
'I
will argue below that in fact they are not even coextensive—that
necessary a
posteriori truths,
and probably contingent a
priori truths,
both exist.' (Kripke 1980, p.38.)
An
aspect of the character of the notion of necessity de dicto is
captured vividly in some of Kripke's intuitive appeals regarding the
necessary a posteriori, in particular with the use of the
phrase 'given that', and similar language. For instance, if I think
some object I have encountered empirically, a, is the same
object as I have encountered empirically in other situations, b,
then – while I might conceivably turn out to be wrong, i.e. while
it might turn out to be the case that a is distinct from b
– given that a is indeed b, then a couldn't
have been distinct from b;
'a = b'
is necessary.
Regarding
the contingent a
priori, perhaps the
most straightforward and instructive type of case occurs when a name
is stipulated to refer to whatever object satisfies some description,
where the description is of a sort where an object satisfying it
could have failed to satisfy it. So if I stipulate that 'a'
is to refer to the inventor of the zip (if there was an inventor of
the zip), then the proposition 'a,
if there is an a,
invented the zip' is a
priori: in virtue of
the way I have set 'a'
up to work, it just can't turn out empirically that a
exists and yet didn't
invent the zip after all. Now suppose that there is an inventor of
the zip. In
that case, the proposition 'a,
if there is an a,
invented the zip', while a
priori, is contingent:
someone else could have invented the zip.
We have now characterized our topic, first intensionally, by taking
and modifying slightly Kripke's famous characterization, and then
extensionally, by pointing to two striking types of cases. The next question
we must address is 'What is the problem or task in relation to the
topic, to which your account is a response?' I will concentrate on this in a future post.
References
Kripke, Saul A. (1980). Naming and Necessity. Harvard University Press. (First published 1971.)
Williamson, Timothy & Antonsen, Paal (2010). Modality & Other Matters: An Interview with Timothy Williamson. Perspectives: International Postgraduate Journal of Philosophy 3 (1):16-29.
Salmon, Nathan U. (2005). 'The Logic of What Might Have Been' in Metaphysics, Mathematics, and Meaning. Oxford University Press. Article originally published in 1989.
Stoljar, Daniel (2006). Ignorance and Imagination: The Epistemic Origin of the Problem of Consciousness. Oxford: Oxford University Press.
van Invagen, Peter (2015). 'Nothing is Impossible' in God, Truth, and other Enigmas, Szatkowski, Miroslaw (ed.),. De Gruyter.
