Timeline for Why will an implication be true when the hypothesis is false? [duplicate]
Current License: CC BY-SA 3.0
14 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| S Sep 11, 2017 at 21:48 | history | suggested | Heptapod | CC BY-SA 3.0 | Improved the formatting. |
| Sep 11, 2017 at 21:40 | review | Suggested edits | |||
| S Sep 11, 2017 at 21:48 | |||||
| Aug 16, 2017 at 14:17 | comment | added | Dan Christensen | Also see my answer here to a similar question at math.stackexchange.com/questions/1551320/… | |
| Aug 16, 2017 at 12:24 | comment | added | Yes | The closure of this question happened when I was typing an answer... Shoot :). Note that, if you let "$A \Rightarrow B$ holds" be defined by "$\overline{A}$ or $B$ holds", then from the definition of "or" you can answer your question directly. Intuitively speaking, you may view the rule of inference this way. If your teacher promise you (weirdly) that "if you get an A+ this time, then you can graduate directly from then on under my permission", then when will he break the promise? When and only when you get an A+ that time and he does not make your graduation happen! | |
| Aug 16, 2017 at 12:20 | history | closed | Ennar 5xum Graham Kemp not all wrong Hans Lundmark | Duplicate of In classical logic, why is $(p\Rightarrow q)$ True if both $p$ and $q$ are False? | |
| Aug 16, 2017 at 12:03 | comment | added | Ataulfo | What about ALL TRIANGLES ARE RECTANGULAR $\Rightarrow$ SOME TRIANGLES ARE RECTANGULAR? | |
| Aug 16, 2017 at 11:57 | comment | added | Aashish Loknath Panigrahi | @Piquito I think the proposition "All triangles are Rectangles" is false because no triangle can be a rectangle and no rectangle can be a triangle. | |
| Aug 16, 2017 at 11:52 | comment | added | Aashish Loknath Panigrahi | Sorry for the typo. I was trying to say why would implication be true when hypothesis is false or in short why would implication be false only when p is true but q is falsw | |
| Aug 16, 2017 at 11:50 | history | edited | Aashish Loknath Panigrahi | CC BY-SA 3.0 | deleted 1 character in body |
| Aug 16, 2017 at 11:49 | review | Close votes | |||
| Aug 16, 2017 at 12:25 | |||||
| Aug 16, 2017 at 11:41 | answer | added | GregT | timeline score: 1 | |
| Aug 16, 2017 at 11:41 | comment | added | José Carlos Santos | You are wrong. The implication is false only when $p$ is true and $q$ is fase. | |
| Aug 16, 2017 at 11:40 | answer | added | Marc van Leeuwen | timeline score: 3 | |
| Aug 16, 2017 at 11:24 | history | asked | Aashish Loknath Panigrahi | CC BY-SA 3.0 |