Timeline for Can an argument be valid even if its conclusion has nothing to do with its premisses?
Current License: CC BY-SA 4.0
7 events
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| Sep 20, 2023 at 10:08 | comment | added | Speakpigeon | @Stef "* I say "Proposition P1 is true" because proposition P1 is true. " Clearly not, because it is not. 2. "*No interviewer has ever faulted me for being logical" Did you ever say something like P1 in a job interview? This is what I mean by "do P1". 3. "P1 is (...) a true proposition, regardless of why we "say this"" But P1 is not true, whatever you say. | |
| Sep 20, 2023 at 8:58 | comment | added | Stef | @Speakpigeon I don't understand your comment. I say "Proposition P1 is true" because proposition P1 is true. No interviewer has ever faulted me for being logical. I don't know what you mean by "do P1" or "don't do P1". P1 is a proposition, not an action. It's a true proposition, regardless of why we "say this", regardless of your political inclinations, and regardless of horses and their shoes. | |
| Sep 20, 2023 at 5:48 | comment | added | Speakpigeon | @Stef "Proposition P1 is true" I gather that you say this because the antecedent "Alfred has both exactly 20 mice and exactly 30 mice" is false. This is the horseshoe theory, but I doubt anyone would ever dare assert this sort of meaningless implication in real life contexts, say in a job interview or campaigning to get re-elected chairman of banking association. We don't do P1 for the same reason that we don't do P2. | |
| Sep 17, 2023 at 20:07 | comment | added | Stef | Thank you for your comment. Had it not opened with an accusation, it might have been welcome. | |
| Sep 17, 2023 at 20:05 | comment | added | Bumble | You are confusing truth with validity. Your use of the word 'thus' in P2 appears to be a kind of turnstile, so P2 is not a proposition but two propositions. It consists of a premise "Alfred has both exactly 20 mice and exactly 30 mice" and a conclusion "Bob has 5 mice". As an argument, this is valid in classical logic, but it is unsound, since not all its premises are true. The question is asking whether the argument is valid. At the end, you use the word 'wrong' to describe an argument, but it is wrong by virtue of being unsound, not invalid. | |
| Sep 17, 2023 at 19:29 | history | edited | Stef | CC BY-SA 4.0 |
added 417 characters in body
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| Sep 17, 2023 at 19:24 | history | answered | Stef | CC BY-SA 4.0 |