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Single Idea 12010

[filed under theme 5. Theory of Logic / E. Structures of Logic / 2. Logical Connectives / d. and ]

Full Idea

The typical semantic account of validity for propositional connectives like 'and' presupposes that meaning is given by truth-tables. On the natural deduction view, the meaning of 'and' is given by its introduction and elimination rules.

Gist of Idea

Is the meaning of 'and' given by its truth table, or by its introduction and elimination rules?

Source

Graeme Forbes (The Metaphysics of Modality [1985], 4.4)

Book Ref

Forbes,Graeme: 'The Metaphysics of Modality' [OUP 1985], p.82

The 25 ideas from 'The Metaphysics of Modality'

11885 Only individual essences will ground identities across worlds in other properties [Forbes,G, by Mackie,P]
11888 Identities must hold because of other facts, which must be instrinsic [Forbes,G, by Mackie,P]
12003 De re modal formulae, unlike de dicto, are sensitive to transworld identities [Forbes,G]
12004 Counterpart theory is not good at handling the logic of identity [Forbes,G]
12005 The symbol 'ι' forms definite descriptions; (ιx)F(x) says 'the x which is such that F(x)' [Forbes,G]
12008 Unlike places and times, we cannot separate possible worlds from what is true at them [Forbes,G]
12009 The problem with possible worlds realism is epistemological; we can't know properties of possible objects [Forbes,G]
12007 Possible worlds are points of logical space, rather like other times than our own [Forbes,G]
12010 Is the meaning of 'and' given by its truth table, or by its introduction and elimination rules? [Forbes,G]
12014 An individual essence is a set of essential properties which only that object can have [Forbes,G]
12015 Non-trivial individual essence is properties other than de dicto, or universal, or relational [Forbes,G]
12013 Essential properties depend on a category, and perhaps also on particular facts [Forbes,G]
12012 Essential properties are those without which an object could not exist [Forbes,G]
12011 Transworld identity concerns the limits of possibility for ordinary things [Forbes,G]
12016 The problem of transworld identity can be solved by individual essences [Forbes,G]
12017 In all instances of identity, there must be some facts to ensure the identity [Forbes,G]
12020 An individual might change their sex in a world, but couldn't have differed in sex at origin [Forbes,G]
12021 Haecceitism attributes to each individual a primitive identity or thisness [Forbes,G]
12022 Same parts does not ensure same artefact, if those parts could constitute a different artefact [Forbes,G]
12023 Vagueness problems arise from applying sharp semantics to vague languages [Forbes,G]
12024 If we combined two clocks, it seems that two clocks may have become one clock. [Forbes,G]
12025 Artefacts have fuzzy essences [Forbes,G]
12027 There must be a plausible epistemological theory alongside any metaphysical theory [Forbes,G]
12028 De re necessity is a form of conceptual necessity, just as de dicto necessity is [Forbes,G]
12029 We believe in thisnesses, because we reject bizarre possibilities as not being about that individual [Forbes,G]