Propositional Logic Truth Trees (and, or, not)

In this video on #Logic / #PhilosophicalLogic I introduce truth trees, inconsistent sets of wffs, and rules for disjunction, conjunction, and the negation. We talk about disjunction decomposition, conjunction decomposition, double negation, negated disjunction decomposition, and negated conjunction decomposition. Then, we do an example of a truth tree.
0:00 [Intro]
0:17 [What is a truth tree?]
2:51 [Rule: Conjunction Decomposition]
4:04 [Rule: Disjunction Decomposition]
5:02 [Rule: Double Negation]
5:20 [Rule: Negated Conjunction Decomposition]
7:39 [Rule: Negated Disjunction Decomposition]
8:47 [Inconsistency and Example #1]
10:51 [Example #2]
Follow along in the Logic playlist: • Logic in Philosophy an...
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-Playlists-
Logic: • Logic in Philosophy an...
-Recommended Textbooks-
The Logic Book: amzn.to/31h2qR8
Modal Logic for Philosophers (Garson): amzn.to/3dECGn4
A Friendly Introduction to Mathematical Logic: amzn.to/37hMYZa
An introduction to Formal Logic with Philosophical Applications: amzn.to/3j3J9sx
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[@T-The-K]

This one took me a bit longer to fully grasp, a lot of rewinding but i figured out everything (hopefully) so looking forward to the excercises!

[@QuocDatPhung]

This is amazing!

[@jeremiahsilva7458]

I'm too dumb to get it.

[@DarrenMcStravick]

@@jeremiahsilva7458 Wrong.

[@flirkvslife2385]

I don’t understand why we’re branching out from ~R, and also, why did we put P Q instead of P R in the branch? On top of that, I also don’t get why Q branches into P AND R!!

[@salmanizzadin]

📝

[@stephaniew7501]

Where is the solution video?

[@lucarius4465]

In our class we call the NCD and the NDD 'The Morgan'. I quite prefer that name over this spaghetti alternative xD

[@paulcarello6390]

1) (P ∨ Q) ∧ (P ∨ R) ⇔ (P ∨ Q) ∧ ~(~P ∧ ~R) ... De Morgans
∴ (P ∨ Q) and ~(~P ∧ ~R) ... ∧ deconstruction
2) (~P ∧ ~R)
From 1 and 2
~(~P ∧ ~R) is TRUE and (~P ∧ ~R) is TRUE ... this is a contradiction
∴ 1 and 2 are NOT consistent.