structure for 'Theory of Logic'    |     alphabetical list of themes    |     expand these ideas

5. Theory of Logic / B. Logical Consequence / 7. Strict Implication

[it can never be that P is true and Q is false]

5 ideas
Lewis's 'strict implication' preserved Russell's confusion of 'if...then' with implication [Quine on Russell/Whitehead]
Russell's implication means that random sentences imply one another [Lewis,CI on Russell/Whitehead]
Where a conditional is purely formal, an implication implies a link between premise and conclusion [Devlin]
Strict implication says false propositions imply everything, and everything implies true propositions [Mautner]
Necessary implication is called 'strict implication'; if successful, it is called 'entailment' [Girle]