|Necessity, philosophy: different kinds of necessity are distinguished, differing in their strength. For example, physical, logical or metaphysical necessity. See also necessity de dicto, necessity de re.|
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|Necessary/Not a priori: E.g. Goldbach’s assumption: It will turn out, then with necessity
I would suggest, however, that it is not a necessary fact that Aristotle has the logical sum of the properties which are usually attributed to him.
Kripke (VsTradition): Molecular motion: necessarily identical with heat. We have discovered it, but it could not have been otherwise.
Physical truths necessary:
E.g. heat = molecular motion - but has no analogy to mind-brain identities.
Definition Necessity/Kripke: Such identity assertions in which both expressions designate rigidly. E.g. »Water is H20". Water could not have been something else. It is essential for water that it is this material with this atomic structure. Where there is no H20, there is no water.
Frank I 121f
Necessary/Kripke: Compounds formed with two or more rigid designation expressions - E.g. that pain simply feels like pain - contingent/Kripke: e.g. the fact that there are living beings on this planet (namely us) who feel heat a certain way - E.g. That heat feels to us as it feels - Tradition: brain condition could also occur without pain
Necessary/essential properties/KripkeVsTradition: The type of picking out pain (by experience) and the brain state (configuration of molecules) in both cases is essential and not accidental - the brain state could be singled out through contingent facts, but not the pain.
Kripke I 144
Necessary properties do not have to belong to the meaning. (Periodic Table later
discovered). Scientific discoveries do not change the meaning. Meaning does not arise from properties.
Stalnaker I 188
Necessary a posteriori/Kripke/Stalnaker: Typical cases: statements that contain names e.g. Hesperus = Phosphorus (see below: they were determined by different causal chains) - statements about natural kinds: e.g. "the atomic weight of gold is 79".
Name und Notwendigkeit Frankfurt 1981
S. A. Kripke
Outline of a Theory of Truth (1975)
Recent Essays on Truth and the Liar Paradox, R. L. Martin (Hg), Oxford/NY 1984
M. Frank (Hrsg.)
Analytische Theorien des Selbstbewusstseins Frankfurt 1994
Ways a World may be Oxford New York 2003