more on this theme | more from this text
Full Idea
The distinction between sentences and the abstract propositions that they express is one of the key ideas of logic. A logical argument consists of propositions, assembled together in a systematic fashion.
Gist of Idea
The distinction between sentences and abstract propositions is crucial in logic
Source
Keith Devlin (Goodbye Descartes [1997], Ch. 2)
Book Ref
Devlin,Keith: 'Goodbye Descartes: the end of logic' [Wiley 1997], p.27
A Reaction
He may claim that arguments consist of abstract propositions, but they always get expressed in sentences. However, the whole idea of logical form implies the existence of propositions - there is something which a messy sentence 'really' says.
8072 | Sentences of apparent identical form can have different contextual meanings [Devlin] |
8073 | How do we parse 'time flies like an arrow' and 'fruit flies like an apple'? [Devlin] |
8076 | The distinction between sentences and abstract propositions is crucial in logic [Devlin] |
8075 | Space and time are atomic in the arrow, and divisible in the tortoise [Devlin] |
8081 | 'No councillors are bankers' and 'All bankers are athletes' implies 'Some athletes are not councillors' [Devlin] |
8082 | Where a conditional is purely formal, an implication implies a link between premise and conclusion [Devlin] |
8087 | Golden ages: 1900-1960 for pure logic, and 1950-1985 for applied logic [Devlin] |
8085 | Modern propositional inference replaces Aristotle's 19 syllogisms with modus ponens [Devlin] |
8086 | Predicate logic retains the axioms of propositional logic [Devlin] |
8088 | People still say the Hopi have no time concepts, despite Whorf's later denial [Devlin] |
8091 | Situation theory is logic that takes account of context [Devlin] |
8089 | Montague's intensional logic incorporated the notion of meaning [Devlin] |
8092 | Logic was merely a branch of rhetoric until the scientific 17th century [Devlin] |