De dicto and de re

De dicto and de re are two phrases used to mark a distinction in intensional statements, associated with the intensional operators in many such statements. The distinction is used regularly in metaphysics and in philosophy of language.[1]

The literal translation of the phrase "de dicto" is "about what is said",[2] whereas de re translates to "about the thing".[3] The original meaning of the Latin locutions is useful for understanding the living meaning of the phrases, in the distinctions they mark. The distinction is best understood by examples of intensional contexts of which we will consider three: a context of thought, a context of desire, and a context of modality.

Context of thought

There are two possible interpretations of the sentence “Peter believes someone is out to get him”. On one interpretation, ‘someone’ is unspecific and Peter suffers a general paranoia; he believes that it is true that a person is out to get him, but does not necessarily have any beliefs about who this person may be. What Peter believes is that the predicate ‘is out to get Peter’ is satisfied. This is the de dicto interpretation.

On the de re interpretation, ‘someone’ is specific, picking out some particular individual. There is some person Peter has in mind, and Peter believes that person is out to get him.

In the context of thought, the distinction helps us explain how people can hold seemingly self-contradicting beliefs. Say Lois Lane believes Clark Kent is weaker than Superman. Since Clark Kent is Superman, taken de re, Lois’s belief is untenable; the names ‘Clark Kent’ and ‘Superman’ pick out an individual in the world, and a person (or super-person) cannot be stronger than himself. Understood de dicto, however, this may be a perfectly reasonable belief, since Lois is not aware that Clark and Superman are one and the same.

Context of desire

Consider the sentence "Jana wants to marry the tallest man in Fulsom County". It could be read either de dicto or de re; the meanings would be different. One interpretation is that Jana wants to marry the tallest man in Fulsom County, whoever he might be. On this interpretation, what the statement tells us is that Jana has a certain unspecific desire; what she desires is that a certain situation should obtain, namely, Jana's marrying the tallest man in Fulsom County. The desire is directed at that situation, regardless of how it is to be achieved. The other interpretation is that Jana wants to marry a certain man, who in fact happens to be the tallest man in Fulsom County. Her desire is for that man, and she desires herself to marry him. Again, the first interpretation, "Jana desires that she marry the tallest man in Fulsom County", is the de dicto interpretation. The second interpretation, "Of the tallest man in Fulsom County, Jana desires that she marry him", is the de re interpretation.

Another way to understand the distinction is to ask what Jana would want if the man who was the tallest man in Fulsom County, at the time the original statement was made, were to lose his accolade to a 9 foot tall immigrant, such that he was no longer the tallest man in Fulsom County. If she continued to want to marry that man – and, importantly, perceived this as representing no change in her desires – then she could be taken to have meant the original statement in a de re sense. If she no longer wanted to marry that man but instead wanted to marry the new tallest man in Fulsom County, and saw this as a continuation of her earlier desire, then she meant the original statement in a de dicto sense.

Context of modality

The number of discovered chemical elements is 118. Take the sentence "The number of chemical elements is necessarily greater than 100". Again, there are two interpretations as per the de dicto / de re distinction. The first interpretation, de dicto, is that things could not have gone differently, with the number of elements fewer than 100. Even if the inner workings of the atom could differ, there could not be fewer than 100 elements. The second interpretation, de re, is that things could not have gone differently with the number 118 turning out to be fewer than 100. Intuitively, this claim is true. Of all the ways the world could have turned out, presumably there are no possibilities wherein 118 is fewer than 100. That 118 is greater than 100 is a necessary fact. The de dicto interpretation seems to yield a false statement. The de re interpretation seems to yield a true statement.

Another example: "The President of the USA in 2001 could not have been Al Gore". This claim seems false on a de dicto reading. Presumably, things could have gone differently, with the Supreme Court not claiming that Bush had won the election. But it looks more plausible on a de re reading. After all, we might skeptically wonder of George W. Bush whether he could have been Al Gore. Indeed, assuming that being George Bush is an essential feature of George Bush and that this feature is incompatible with being Al Gore, a de re reading of the statement is true.

Representing de dicto and de re in modal logic

In modal logic the distinction between de dicto and de re is one of scope. In de dicto claims, any existential quantifiers are within the scope of the modal operator, whereas in de re claims the modal operator falls within the scope of the existential quantifier. For example:

De dicto: \Box \exists{x} Ax Necessarily, some x is such that it is A
De re: \exists{x} \Box Ax Some x is such that it is necessarily A

Willard van Orman Quine

Willard Van Orman Quine refers to D. Kaplan, who in turn credits Montgomery Furth for the term vivid designator in his paper Reference and Modality. He examines the separation between de re and de dicto statements and does away with de re statements, because de re statements can only work for names that are used referentially.[4] In fact, both rigid designators and vivid designators are similarly dependent on context and empty otherwise. The same is true of the whole quantified modal logic of necessity because it collapses if essence is withdrawn.[5]

See also

References

  1. ↑ Semantics Archive discussion
  2. ↑ http://www.oxforddictionaries.com/definition/english/de-dicto
  3. ↑ http://www.oxforddictionaries.com/definition/english/de-re?q=de+re
  4. ↑ Andrea Bonomi, On Quine: Transparency and Specificity in Intentional Contexts, 1995, p.183
  5. ↑ Quine, W.V.O., Quintessence: Reference and Modality, 2004, pp. 356–357

Bibliography

External links