Natural Deduction Proofs: practise examples | Attic Philosophy

How do Natural Deduction proofs work in logic? In this video, I show you how it works by going through some example proofs. 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!

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00:00 intro
00:42 recap of the rules
01:10 example 1
03:57 example 2
05:25 Proof Strategy
08:31 example 3
10:41 proving equivalence
11:21 example 4
14:21 example 5: de Morgan equivalence
16:46 important logical equivalences
17:22 wrap up

More on natural deduction:

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#logic #proof #naturaldeduction

[sjoerdv]

How has this guy only 2.61k subs this is level teaching skills thanks so much I will post how my exam tomorrow went

[frankavocado]

That little bit of strategy completely unlocked all of natural deduction for me, thanks!

[Reva]

I was honestly stranded cause I didn't get how my teacher explained it and I have a test tomorrow you really helped me thank you
and I would love to see you post again even if I'm new to this channel thank you

[alessf]

Hello Sir ! Your videos are absolutely wonderful. They're both short and extremely complete + very easy to understand. Thanks a lot for your hard work !

[jybhitk]

thank you so much, without you, I could never understand the natural deduction

[gkozgkeiros]

you taught me in less than 20 minutes what my prof failed do whole semester.cheers

[macwas]

Thanks so much for making this video! :) It helped a lot where my lecturer didn't give great examples or explain them well as he went through

[themysteriousfox]

I couldn't figure this out until I watched your video, thank you!

[userozancinci]

YOU MY MATE !!! YOU JUST MADE MY LIFE WAY EASIER!! IF I WERE NEXT TO YOU RIGHT NOW, I WOULD GIVE YOU A BIG HUG!!! THIS WAS THE TOPIC MY PROFF COULDNT EXPLAİN PROPERLY FOR 2.5 HOURS! APPRECIATE THAT VIDEO!!!!

[MrLordAzkar]

Amazing video! Thank you so much for explaining even the tiniest details, it helped my understanding a lot!

[natheetarnpanyakorn]

Hope you get a lot of subs soon! Thank you for great content.

[theMelMxshow]

Now I'm teaching logic, this is SOOO helpful!!! thanks so much!

[jasnesciemnienie]

These videos are very good. Thank you!

[BillboMC]

this is my favourite tutorial video on YouTube. not my first comment here!

[toe_fans]

Your channel is a hidden gem, I absolutely love your channel

question:

Is

A \turnstile B

equivalent to

\turnstile A --> B

?

[csperi-peri]

Great video, not many videos show proper sub-proofs

[sohambasu]

my exam is on this Monday. Can you please solve my query:

for example 4, when we were proving from right side to left side, how did you introduce ~B from A ? what rule is that ?

[vuppalasrinivasarao]

thank you so much sir
I was struggling in it until I found your video...but now I'm not !

[sohambasu]

Using the above process, we are able to prove left side from right hand side and vice versa.

But if question says to prove the validity by natural deduction, and we have an expression. then how do we proceed with it ? we don't have any right hand side or left hand side in that case.

A question in my paper has come like:
Prove by natural deduction the validty of:

(P ->Q) -> (P -> ( P ^ Q))

Please help.

[gonzajuarez]

Heyy thanks for the video. I was just trying to prove the tautologies at the end of the video and came across a problem with one of DeMorgan laws. That one of ~(A ^ B) -| |- ~A v ~B. I can't figure how to start the proof that assumes ~(A ^ B) and concludes ~A v ~B. I have no problem with a proof for ~~(A ^ B) -| |- ~(~A v ~B) since I can use double negation and do a lot more with A ^ B. But comming up with something for ~(A ^ B) is a bit tricky for me