Rules for Natural Deduction | Attic Philosophy
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- เผยแพร่เมื่อ 10 พ.ย. 2020
- Natural Deduction might be the simplest way to do proofs in logic. But how does it work? Let's find out! The previous video introduced the general idea. In this video, we go through the rules and how to use them.
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This is part of a series of videos introducing the basics of logic. If there’s topics you’d like covered, leave me a comment below!
Links:
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#logic #proof #naturaldeduction
This channel is underrated.
This will be an evergreen channel for students.
Thanks, I hope so!
Hi there! Just wanted to offer my compliments: this is a very well produced series (all of the natural deduction proof videos)! There isn't currently that much out there on more advanced logic topics. It would be helpful if you would also make a video to explain predicate natural proofs maybe, especially covering the universal quantifiers. Overall just good job and keep it up!
Thanks! First-order natural deduction will be coming in a week or two.
I’m recommending your videos to my entire logic class haha. You’re channel is so helpful
Oh great! Hope they find the videos useful too.
Very well explained! This is the most succinct explanation for natural deduction rules that I’ve heard yet.
Thanks!
great video thanks buddy! helped me a lot
Absolutely love your videos. I wish there were more. Only complaint is that the intro and outro end up hurting my ears if I don't turn them down fast enough.
Thanks - there’ll be more logic videos coming next month. Yeah I messed up the volume levels on these videos, sorry about that! nothing I can do about these now but the newer videos are much better.
Thank you so much! These videos helped me so much with my exams. Appreciate it a lot.
Great, glad they helped.
I am just amazed. Thank you for your work. You are soooo helpful and so much better than my prof in uni T_T
You're welcome! Glad the video was useful.
Very useful and educational video!!
Thanks!
This is so helpful for understanding my class!!!!
Great, glad it helped!
thank you so much man
You’re welcome!
Hey Mark. Firstly, I think that your account is absolutely brilliant. Thanks for all the great content! Also, I have a question that I would like to ask you please. So, I'm currently studying MA Philosophy at King's and I'd really appreciate some advice on how to know when to stop editing an essay! When I'm near a deadline, I often have a moment where I think the paper is probably as good as it's going to get, but I also feel too guilty for stopping work on it ... as if that's not a good use of the short amount of time that I have left before the deadline. I'm aware that there's probably no one straightforward answer for this, but any thoughts on when to just call it 'done' and press submit? Best, Izzi
Hi Izzy, good question!I guess there is no definite answer, but you always get diminishing returns with editing: The first pass improves your essay loads, the second maybe a bit more, the third maybe a tiny bit. I think the best way to edit is to leave a long gap between when you finish writing and when you edit. Then, it’s almost like you’re editing somebody else’s writing, you can be more objective, and you spot more typos that way. Reading out loud is also a good way of checking the flow of the sentences and whether they make as much sense on paper as they did in your head. When it comes to submitting papers for publication, it’s probably best to get a supervisors advice on when it’s ready to go.
@@AtticPhilosophy Thanks very much for your kind response :) I'm definitely on board with taking a long break between writing and editing, as well reading outloud. They definitely help me too! I'd never thought of editing as being of deminishing returns before, so I'll be adding that to the toolkit for sure. I think it'll help me justify finishing editing 'early' as well - no significant point in doing something past the point of diminishing returns!! Thanks again, Mark. Massively appreciated.
Please provide references for or more explanation for the Folsom constant... Thank you....
It’s the constant that is always false. Not sure who first used it, but not the kind of thing you need to reference.
I've got, as always, questions: why isn't there a rule of replacement of equivalent formulas in this system of natural deduction? And also, why is there a rule for indirect proofs and also a reductio ad absurdum rule, as if they were different beasts?
Natural deduction has intro and elimination rules for each connective. Replacement rules don’t fit that pattern (but are fine in other proof systems). Indirect proof isn’t the same as RAA: one gets you p from contradicting ~p, whereas RAA gets you ~~p. That’s basically why RAA but not IP is intuitionistically valid.
hey you did that computerphile video on the halting problem
I did! Glad you found this channel too. There’s more on Turing & comp-sci related stuff here.
@@AtticPhilosophy mate i absolutely blitzed my ND question in my exam thanks to you. Your explanations are so clear compared to everything else on the topic. So thanks again
just to say thankyou
Thanks!
In OR elimination, How did we conclude C and what is C?
If you've got AvB, and you can find any other sentence C which follows from B on its own and also follows from B on its own, then you can infer C from AvB.
@@AtticPhilosophy Oh okay. That cleared it up. You meant "follows from A on its own and also follows from B on its own" right? These videos have helped me a lot BTW. Thanks a ton for such awesome content.
I cast magic and assume I got a 10 on the exam. Now i just have to prove it. Jk. Although your explanations definitely helped me a lot. Thank you
6:25 and we’re no longer learning propositional logic but instead Harry Potter spells
haha good one! [points wand] Reductio!