Saul Kripke
(Copyright © 2005 Piero Scaruffi | Legal restrictions - Termini d'uso )

Philosophy of Mind
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Synopsis:
  • What is necessarily or possibly true
  • Modal logic with four operators: true, false, possible, necessary
  • A property is necessary if it is true in all worlds, a property is possible if it is true in at least one world.
  • False sentences may have different intensions (false but possible, false and impossible)
  • Kripke's semantics can interpret all sentences that can be reduced to "it is possible that" and "it is necessary that"
  • The truth value of a sentence is always relative to a particular world
  • A necessary truth is one that is true in all possible worlds (e.g., 2+2=4)
  • A possible truth is one that is true in some world (e.g., 'I am a millionaire')
  • A proposition does not have a truth value, but a set of truth values, one for each possible world
  • Tarski's theory is purely extensional (for each model the truth of a predicate is determined by the list of objects for which it is true), whereas Kripke's modal logic is intensional.
  • Proper names and names of natural kinds are "rigid designators", i.e. in every possible world they designate the same object
  • They are linked to their referents through a causal chain. If a scientist discovered that water in not H20, water would still be called water and would still be what it is today

(Copyright © 2005 Piero Scaruffi | Legal restrictions - Termini d'uso )