display all the ideas for this combination of philosophers
4 ideas
6877 | Entailment is logical requirement; it may be not(p and not-q), but that has problems [Mautner] |
Full Idea: Entailment is the modern word saying that p logically follows from q. Its simplest definition is that you cannot have both p and not-q, but this has the problem that if p is impossible it will entail every possible proposition, which seems unacceptable. | |
From: Thomas Mautner (Penguin Dictionary of Philosophy [1996], p.169) | |
A reaction: The word 'entail' was introduced by G.E. Moore in 1920, in preference to 'imply'. It seems clear that we need terms for (say) active implication (q must be true if p is true) and passive implication (p must be false if q is false). |
6880 | Strict implication says false propositions imply everything, and everything implies true propositions [Mautner] |
Full Idea: Strict implication [not(p and not-q)] carries the paradoxes that a false proposition (p) implies any proposition (q), and a true proposition (q) is materially implied by any proposition (p). | |
From: Thomas Mautner (Penguin Dictionary of Philosophy [1996], p.270) | |
A reaction: This seems to show that we have two drastically different notions of implication; one (the logician's) is boring and is defined by a truth table; the other (the ordinary interesting one) says if you have one truth you can deduce a second. |
6879 | 'Material implication' is defined as 'not(p and not-q)', but seems to imply a connection between p and q [Mautner] |
Full Idea: 'Material implication' is a term introduced by Russell which is defined as 'the conjunction of p and not-q is false', but carries a strong implication that p implies q, and so there must be some kind of connection between them, which is misleading. | |
From: Thomas Mautner (Penguin Dictionary of Philosophy [1996], p.270) | |
A reaction: Mautner says statements of the form 'if p then q' are better called 'conditionals' than 'material implications'. Clearly there is a need for more precise terminology here, as the underlying concepts seem simple enough. |
6878 | A person who 'infers' draws the conclusion, but a person who 'implies' leaves it to the audience [Mautner] |
Full Idea: 'Implying' is different from 'inferring', because a person who infers draws the conclusion, but a person who implies leaves it to the audience to draw the conclusion. | |
From: Thomas Mautner (Penguin Dictionary of Philosophy [1996], p.279) | |
A reaction: I had always taken it just that the speaker does the implying and the audience does the inferring. Of course a speaker may not know what he or she is implying, but an audience must be aware of what it is inferring. |