De dicto and de re

With the notation de dicto and de re (Latin for " about what was said " and " about the matter " ) describing in logic, philosophy of language and ontology a difference in meaning in intensional operators such as the Modalbegriffen possible and necessary. In the case of a modality " de dicto " results in the necessity of the way how a certain thing is described, in the case of a modality " de re" on the merits of the distinction of modality de re and modality de dicto to go Thomas Aquinas back.

Explanation

The distinction of a modality de dicto and de re is here everyday language explained in the model of possible worlds and formal logic:

• In ordinary language:

• Model of possible worlds:

• A proposition p is possible if there is at least one possible world W such that p is true in W.
• A proposition p is necessary if there is 1- n is true in every possible world where p is true.

• An object S has the property F accidental or possibly only if there is at least one possible world W, exists in the S and F has the property.
• An object S has the property F necessary if W 1 -n in every possible world exists in the S, S has the property F ".

• Formal Logic:

Implications of the distinction

It has long been the view in the (modern) philosophy of language that necessity, possibility and contingency " merely de dicto can be understood." This has an extensional equation of necessity and apriority result. Conversely, one can a de re - recognize modality correct only if one distinguishes between necessity and apriority.

De re - arrangements led to a revival of Essentialismusdebatte, ie the question of necessary properties. If we accept them, is close to an affirmation of essentialism.

Discussion of the de re - necessity

Critique of De -re- necessity ( Quine )

Some philosophers reject the assumption of a de re modality and keep only the de dicto modality useful. According to this view need is justified in the language and it makes no sense to ascribe such things as necessary properties.

In this sense, one reads about in the American philosopher Willard Van Orman Quine: "As far as we are talking purely indicative of [ a ] subject, [ ... ] it is not even hinted useful to classify some of its properties as necessary and others as contingent. "). A background for this is that it is difficult or impossible to specify criteria for distinguishing between necessary and non- necessary properties; another are paradoxical or surprising consequences: "It is conceivable that one says mathematicians are necessarily rational and not necessarily two-legged, while cyclists are necessarily bipedal, but not necessarily rational. What, then, is with an individual that includes both mathematics and cycling to its special features? Is this concrete individual necessary rational and contingently two-legged or vice versa? ".

Defense of the de re - necessity ( Kripke )

A defender of the de re - necessity is against Saul Aaron Kripke. He argues that the notion of a description independent necessity or possibility of properties intuitive content was: In his example, someone says, by pointing to Nixon. " This is the man who could have lost " ( It's about the U.S. Presidential Election 1968) here Nixon ascribed characteristic is a de re possibility which belongs Nixon independent of any description, it would be completely counterintuitive answer by Kripke. " Oh, no, if it Nixon ' described as, , he would have can lose; but if you describe it as the winner, it's not true of course, that he could have lost. ". The presence of this intuitive content is for Kripke " a very conclusive evidence" that there are essential properties and thus de re modalities.