Great video ! Your videos are really helping me to explain this stuff to people taking their first logic course. What I am still not really sure about, and a lot of them have asked me: What are the strengths and weaknesses of each method if you compare natural deduction and the proof trees. In what situation is one method preferable over the other ?
Thank you very much!I'm a college student from China and now learning propositional logic.The related study resources are in great shortage so I have to use proxy software to learn it.
Hello Dr Jago. Maybe you can do a video about your University years and what lead you to study Philosophy or Logic in the first place. "Why study Philosophy" is probably what most students ask when they sit in a philosophy class for a humanities requirement for graduation; that is, the student is not taking philosophy because they wanted to but the University is a humanities school and "requires" all majors to be well rounded in other disciplines too. I would never take Geology for instance. So why Philosophy Dr Jago? Were you searching to discover who you really are and then you discovered you love wisdom? You wanted to know how does one really "Know something" and you dug deeper into the search of "What is knowledge?" What is your areas of expertise in Philosophy? Can you make a video about YOU and your Pursuit or experiences studying Philosophy? Perhaps share some memorable moments as a student, perhaps funny stories at Uni either of you or one's you witnessed that still make you crack a smile to this day? Can you share more personal memorable moments as a student and may be all the way to you being a lecturer. Surely now as a lecturer you have some funny stories of what some student try to pull off. I would like to see the more personable side of lecturers as well as you are still human. I mean tactful things still related to Philosophy but if something is funny it is funny. Now that might be worth sharing. :) I love the channel so far.
@@AtticPhilosophy Thanks! I was confused about what you were doing. I thought you were somehow trying to prove q&r->p by assuming q and r and applying impl-intro. Now I see you were actually proving ~q from q&r->p, r, and ~p. Makes complete sense!
this was really helpful, thank you! i just have one question - in one of the examples i was trying 'q -> ¬p' simplified into two branches of ¬q and ¬p and i was a bit confused as to why that was? any help on that would be appreciated
Hi Cait! The rule for A -> B splits into two branches, with ~A on the left and B on the right. So in your case, q -> ~p splits into ~q on the left and ~p on the right.
@@AtticPhilosophy That's an interesting point of view, I work in Cryptographic research ( as a rather useless intern ) and I've met several cryptographers with a strong interest in Philosophy :)
Sure, you only need 1 contradiction per branch to close, regardless of what the other sentences are doing. So, suppose your tree starts off with: A B C p ~p You can close it immediately, without having to look at A, B, or C.
For me this was an excellent tutorial. Well chosen examples, imho. What, sort of, annoyed me was that the lecturer was in view so much. Why not a small view of his face on top-right beside the math? It's about math, isn't it? - Maybe the lecturer made the video just to... NO, not going there.
Thank you for this video. It has been a great help to understand proof trees. The world needs more helpful humans like you. Thanks again.
Thanks - glad it was useful!
TOO LOUD MUSIC INTRO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
This is great! I'd love to see a video on proof trees for intuitionistic logic too
Great suggestion! It's on the to-do list
Great video ! Your videos are really helping me to explain this stuff to people taking their first logic course. What I am still not really sure about, and a lot of them have asked me: What are the strengths and weaknesses of each method if you compare natural deduction and the proof trees. In what situation is one method preferable over the other ?
Thank you very much!I'm a college student from China and now learning propositional logic.The related study resources are in great shortage so I have to use proxy software to learn it.
Glad it was helpful! There's some great online resources for learning logic
How is the internet for 'scholars' in China, if I may ask? - Are you completely cut off from Western research outside of basic journals?
This is very helpful. Thank you!
You're very welcome!
Brilliant! Very clear; thanks!
Thanks! Glad you liked. I'll be adding lots more over the next months.
@@AtticPhilosophy Awesome! Does `=' act as an operator in propositional logic? And, if so, is the rule the same as that for the biconditional?
There’s no identity symbol = in propositional logic. There is a biconditional, , and you can treat A B as (A -> B) & (B -> A)
Hello Dr Jago. Maybe you can do a video about your University years and what lead you to study Philosophy or Logic in the first place. "Why study Philosophy" is probably what most students ask when they sit in a philosophy class for a humanities requirement for graduation; that is, the student is not taking philosophy because they wanted to but the University is a humanities school and "requires" all majors to be well rounded in other disciplines too. I would never take Geology for instance. So why Philosophy Dr Jago? Were you searching to discover who you really are and then you discovered you love wisdom? You wanted to know how does one really "Know something" and you dug deeper into the search of "What is knowledge?" What is your areas of expertise in Philosophy? Can you make a video about YOU and your Pursuit or experiences studying Philosophy? Perhaps share some memorable moments as a student, perhaps funny stories at Uni either of you or one's you witnessed that still make you crack a smile to this day? Can you share more personal memorable moments as a student and may be all the way to you being a lecturer. Surely now as a lecturer you have some funny stories of what some student try to pull off. I would like to see the more personable side of lecturers as well as you are still human. I mean tactful things still related to Philosophy but if something is funny it is funny. Now that might be worth sharing. :) I love the channel so far.
Not exactly what you’re asking for, but I did this video on what’s good about a philosophy degree:
ruclips.net/video/1qjuhF-sw_w/видео.html
@@AtticPhilosophy Thank you for the reply Dr. Jago. I will check at the suggested video.
Is this semantic tableaux (like in the Kelly book)?
Yes, same thing.
Thank you so much for this video. Also, have you made a video on Tableau for ALC (Attributive Concept Language with Complements) ?
You’re welcome! I haven’t heard of ALC, is it a kind of description logic?
@@AtticPhilosophy Yes, it is a type of description logic.
So why the double negation of q at 6:26? I was expecting q,r,~p.
It’s the negated conclusion. q&r->p is a premise - don’t negate that.
@@AtticPhilosophy Thanks! I was confused about what you were doing. I thought you were somehow trying to prove q&r->p by assuming q and r and applying impl-intro. Now I see you were actually proving ~q from q&r->p, r, and ~p. Makes complete sense!
this was really helpful, thank you! i just have one question - in one of the examples i was trying 'q -> ¬p' simplified into two branches of ¬q and ¬p and i was a bit confused as to why that was? any help on that would be appreciated
Hi Cait! The rule for A -> B splits into two branches, with ~A on the left and B on the right. So in your case, q -> ~p splits into ~q on the left and ~p on the right.
What do proof trees have to do with Philosophy?
They're part of logic, which is part of philosophy (along with other subjects)
@@AtticPhilosophy That's an interesting point of view, I work in Cryptographic research ( as a rather useless intern ) and I've met several cryptographers with a strong interest in Philosophy :)
@@jonasp4682 Interesting!
Can I close the tree even if there are formulas that have not been expanded?
Sure, you only need 1 contradiction per branch to close, regardless of what the other sentences are doing. So, suppose your tree starts off with:
A
B
C
p
~p
You can close it immediately, without having to look at A, B, or C.
Good
Thanks!
The repeated switching between video and blackboard in the middle of calculations is kind of distracting
Yes, fair point!
It's not gonna close😂
For me this was an excellent tutorial. Well chosen examples, imho. What, sort of, annoyed me was that the lecturer was in view so much. Why not a small view of his face on top-right beside the math? It's about math, isn't it? - Maybe the lecturer made the video just to... NO, not going there.
Haha, thanks for the feedback. Fwiw, others said "too much blackboard is boring!" You can't please everyone!
@@AtticPhilosophy In my country ( Netherlands ) we have a saying, which I can't translate properly, but it's about a "golden mean". :-)
i didn't know ramsey bolton was doing logic tutorials on youtube now
Yeah bit of a career change but what can I say? Sometimes a man wants to put his feet up & think about Gödel.