Rules of Implication Answers I (100 Days of Logic)
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- čas přidán 19. 01. 2014
- A set of four problems and answers for the first four Rules of Implication (Disjunctive Syllogism, Hypothetical Syllogism, Modus Ponens, and Modus Tollens)
Information for this video gathered from The Stanford Encyclopedia of Philosophy, The Internet Encyclopedia of Philosophy, The Cambridge Dictionary of Philosophy, The Oxford Dictionary of Philosophy and more!
Information for this video gathered from The Stanford Encyclopedia of Philosophy, The Internet Encyclopedia of Philosophy, The Cambridge Dictionary of Philosophy, The Oxford Dictionary of Philosophy and more!
At the end of the previous video (Modus Tollens) and at the beginning of this video, the third problem that is presented is different than what is presented as the solution in this video @ 5:13. Specifically, in the initial presentation, P2 is "~pv(~r>s)" and P3 is "~r", whereas in the solution presentation for each of these, both instances of "~r" are replaced with "~q".
Indeed, and the conclusion S is not valid from those originally presented premises
Could you please add an annotation to fix the statement of problem 3 (from around 0:40 to 1:20), replacing both occurrences of "r" with "q"? I spent way too long trying to figure that out. Thank you.
Me too! I spent so much time trying to figure out only to then watch the video and see that it's not "r" haha
Up to this point I pretty much understood everything pretty easily, encountering a few problems here and there, but I got completely lost here, and I've no idea what's going on anymore.
This is how you actually "do" logic. These are step by step logical proofs using the rules of implication that we have learned so far. If you are confused about solving the problems, watch the whole video, see how I solve them, and then go back and see if you can figure them out yourself. The point is that you are using the premises that you have been given and the rules of logic that you have learned to prove that the conclusion follow from the premises.
ty my dude, working out these proofs was really fun, and although I got a few bits and pieces wrong, the previous videos gave just enough info to work them out, and at least attempt them. I hope u never stop making videos, they are super helpful
This was surprisingly fun (like I really enjoyed that). Thanks!
Your videos are great! I really understand these concepts now, logic is so cool
Thanks a lot for this great series, it is really helpful. I am more used to mathematical/programming logic, hence I tend to replace statements by a simplified form whenever possible. Therefore what I did to solve the third problem, is:
P4: ~p v s (P2, P3, MP)
P5: q v s (P4, P1, MP)
P6: s (P5, P3, DS)
It is not the same method as the one presented. Is my deduction wrong?
The rule that i used at the end of the premises that i used to imply this new premise that i have. This confused the hell out of me :S
isn't ~~p just p?
Double negative is a positive, yes. Not sure about the context here.