display all the ideas for this combination of philosophers
5 ideas
11083 | A sentence is necessary if it is true in a set of worlds, and nonfalse in the other worlds [Hanna] |
Full Idea: On my view, necessity is the truth of a sentence in every member of a set of possible worlds, together with its nonfalsity in every other possible worlds. | |
From: Robert Hanna (Rationality and Logic [2006], 6.6) |
11086 | Metaphysical necessity can be 'weak' (same as logical) and 'strong' (based on essences) [Hanna] |
Full Idea: Weak metaphysical necessity is either over the set of all logically possible worlds (in which case it is the same as logical necessity), or it is of a smaller set of worlds, and is determined by the underlying essence or nature of the actual world. | |
From: Robert Hanna (Rationality and Logic [2006], 6.6) | |
A reaction: I take the first to be of no interest, as I have no interest in a world which is somehow rated as logically possible, but is not naturally possible. The second type should the principle aim of all human cognitive enquiry. The strong version is synthetic. |
11084 | Logical necessity is truth in all logically possible worlds, because of laws and concepts [Hanna] |
Full Idea: Logical necessity is the truth of a sentence by virtue of logical laws or intrinsic conceptual connections alone, and thus true in all logically possible worlds. Put in traditional terms, logical necessity is analyticity. | |
From: Robert Hanna (Rationality and Logic [2006], 6.6) |
11085 | Nomological necessity is truth in all logically possible worlds with our laws [Hanna] |
Full Idea: Physical or nomological necessity is the truth of a sentence in all logically possible worlds governed by our actual laws of nature. | |
From: Robert Hanna (Rationality and Logic [2006], 6.6) | |
A reaction: Personally I think 'natural necessity' is the best label for this, as it avoids firm commitment to reductive physicalism, and it also avoids commitment to actual necessitating laws. |
3888 | Hume assumes that necessity can only be de dicto, not de re [Scruton] |
Full Idea: It was one of the assumptions of Hume's empiricism that all necessities are de dicto: i.e. they are artefacts of language. | |
From: Roger Scruton (Modern Philosophy:introduction and survey [1994], 13.5) |