Psychology Dictionary of ArgumentsHome | |||
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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._____________Annotation: The above characterizations of concepts are neither definitions nor exhausting presentations of problems related to them. Instead, they are intended to give a short introduction to the contributions below. – Lexicon of Arguments. | |||
Author | Concept | Summary/Quotes | Sources |
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John Bigelow on Necessity - Dictionary of Arguments
I 105 Necessity/essential/Bigelow/Pargetter: For example, suppose you have to travel within 24h from Melbourne to London. There are different necessities, e.g. to reach a telephone or others, which can be psychological, causal, etc. Possibility: is also ambiguous. For example, today it is physically impossible to get from Melbourne to London in 10 minutes, but perhaps not always. I 106 Necessary/possible/Bigelow/Pargetter: we can alternatively interpret them as "always" and "sometimes". I 224 Natural Laws/Relative Necessity/Bigelow/Pargetter: Assuming we now label a set of A of sentences as natural laws, we also denote a set of C of possible worlds where these laws are true. Nomically necessary: then we can say that each sentence is nomically necessary iff it is true in all possible worlds of C. Nomic necessity/Bigelow/Pargetter: is thus explained in terms of entailment by laws. >Entailment. Natural Laws/Bigelow/Pargetter: Question: How do we pick out the set A of the sentences that are considered to be natural laws? That depends of course on the way the world is. >Natural laws. What is considered a natural law can be different from world to world. It can only be contingently true in one world, or false in another. >Possible Worlds, >Possible Worlds/Bigelow. For example, there are worlds in which Aristotle's law (see above) applies. Then there is a set to every world w Aw of sentences that are laws in w. That determines a set of Cw, of world whose events coincide with the laws in w. I 225 Nomically necessary: is then when sentence p, iff it is true in all worlds in Cw - in all worlds that are compatible with the laws in w. >Entailment. Nomic necessity: Natural laws. I 227 Natural necessity/Lewis/Bigelow/Pargetter: should be explained in terms of laws and not vice versa. I 238 Natural necessity/Bigelow/Pargetter: is not definable by law. It is what makes laws laws!_____________Explanation of symbols: Roman numerals indicate the source, arabic numerals indicate the page number. The corresponding books are indicated on the right hand side. ((s)…): Comment by the sender of the contribution. Translations: Dictionary of Arguments The note [Concept/Author], [Author1]Vs[Author2] or [Author]Vs[term] resp. "problem:"/"solution:", "old:"/"new:" and "thesis:" is an addition from the Dictionary of Arguments. If a German edition is specified, the page numbers refer to this edition. |
Big I J. Bigelow, R. Pargetter Science and Necessity Cambridge 1990 |