In the course of thinking about the de dicto/de re distinction, I pulled the Oxford Companion to Philosophy from the shelf and read the eponymous entry. After being told that the distinction "seems to have first surfaced explicitly in Abelard," I was then informed that the distinction occurs:
. . . in two main forms: picking out the difference between a
sentential operator and a predicate operator, between 'necessarily
(Fa)' and 'a is (necessarily-F)' on the one hand, and on the other
as a way of highlighting the scope fallacy in treating necessarily
(if p then q) as if it were (if p then necessarily-q).
It seems to me that this explanation leaves something to be desired. I have no beef with the notion that the first distinction is an example of a de dicto/de re distinction. To say of a dictum that it is necessarily true if true is different from saying of a thing (res) that it has a property necessarily. Suppose a exists in some, but not all, possible worlds, and that a is F in every possible world in which it exists. Then a is necessarily F, F in every possible world in which it exists. But since there are possible worlds in which a does not exist, then it will be false that 'a is F' is necessarily true, true
in all possible worlds. So the de dicto 'Necessarily, a is F' is distinct from the de re 'a is necessarily F.'
So far, so good. But the distinction between
1. Nec (if p then q)
and
2. If p, then Nec q
is situated entirely on the de dicto plane, the plane of dicta or propositions. The distinction between (1) and (2) is the well-known distinction between necessitas consequentiae and necessitas consequentiis. To confuse (1) and (2) is to confuse the necessity of the consequence with the necessity of the consequent. Or you could think of the mistake as a scope fallacy: the necessity operator in (1) has wide scope whereas the operator in (2) has narrow scope. But what makes (2) de re? What is the res in question? Consider an example:
3. Necessarily, if a person takes Enalapril, then he takes an ACE inhibitor
does not entail
4. If a person takes Enalapril, then necessarily he takes an ACE inhibitor.
A second example:
5. Necessarily, if something happens, then something happens
does not entail
6. If something happens, then necessarily something happens.
It can't be that easy to prove fatalism. The point, however, is that the distinction between (5) and (6) does not trade on the distinction between dicta and rei, between propositions and non-propositions: the distinction is one of the scope of a propositional operator. Our author thus seems wrongly to assimilate the above scope fallacy to a de dicto/de re confusion.
I conclude that the de dicto/de re distinction is a bit of a terminological mess. And note that it is a mess even when confined to the modal context as demonstrated above. If we try to apply the distinction univocally across modal, doxastic, temporal, and other contexts we can expect an even bigger mess. A fit topic for a future post.
Terminological fluidity is a problem in philosophy. It always has been and always will be. For attempts at regimentation and standardization harbor philosophical assumptions and biases -- which are themselves fit fodder for philosophical scrutiny.
Recent Comments