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Single Idea 8082

[filed under theme 5. Theory of Logic / B. Logical Consequence / 7. Strict Implication ]

Full Idea

Implication involves some form of link or causality between the antecedent and the consequent of an if-then; normally it says that the conclusion is a consequence of the premise (where conditionals are just defined by 'true' and 'false').

Gist of Idea

Where a conditional is purely formal, an implication implies a link between premise and conclusion

Source

Keith Devlin (Goodbye Descartes [1997], Ch. 2)

Book Ref

Devlin,Keith: 'Goodbye Descartes: the end of logic' [Wiley 1997], p.48


A Reaction

This distinction is a key one when discussing 'If-then' sentences. Some are merely formal conditionals, but others make real claims about where you can get to from where you are.


The 13 ideas from Keith Devlin

How do we parse 'time flies like an arrow' and 'fruit flies like an apple'? [Devlin]
Sentences of apparent identical form can have different contextual meanings [Devlin]
Space and time are atomic in the arrow, and divisible in the tortoise [Devlin]
Where a conditional is purely formal, an implication implies a link between premise and conclusion [Devlin]
The distinction between sentences and abstract propositions is crucial in logic [Devlin]
'No councillors are bankers' and 'All bankers are athletes' implies 'Some athletes are not councillors' [Devlin]
Predicate logic retains the axioms of propositional logic [Devlin]
Golden ages: 1900-1960 for pure logic, and 1950-1985 for applied logic [Devlin]
Modern propositional inference replaces Aristotle's 19 syllogisms with modus ponens [Devlin]
People still say the Hopi have no time concepts, despite Whorf's later denial [Devlin]
Montague's intensional logic incorporated the notion of meaning [Devlin]
Situation theory is logic that takes account of context [Devlin]
Logic was merely a branch of rhetoric until the scientific 17th century [Devlin]