Conditional statements and deductive reasoning

[andrewchristenson]

How the hell does he write so well with his mouse *_*

[TheYellowWindow]

Sums up a 2 hour lesson in five minuets, thank you.

[meisam]

RonPaulgirls. Yeah, that's great and all but Sal is an educator, not a propagandist. He's teaching you how to think, not what to think. That's the beginning and end of his role. And he's doing a fine job. Bless him.

[rhoadess]

The first and second statement is a conditional sentence (p implies q), the third is the inverse (not p implies not q), the fourth is the contra-positive (not q implies not p), and the fifth is the converse (q implies p). Note that the contra-positive is both the inverse and the converse, and is equivalent to the first.

[mowafkmha]

first 5 seconds of the video made me like and subscribe immiedtly

[arnoldromo]

Still somewhat confused about the third being true but other than that, it made this much clearer :D

[NIGHTMARE-uccg]

Eating spinach makes turn into Arnold?! YISSSS

[happieroc]

I also understand this is implying the statement is true. But if the statement isnt tue, it makes it confusing to reword the entire false statement into another implied true-false statement.

[happieroc]

This seems like opinion and perspective have to be used. It is not definitive and through this section i have found multiple occasions were i can disagree on the overall answer. I think it needs a little reworking. Other than this section, i love this site. I have been able to brush up on the stuff i did in high school, The current classes im taking now and the next course i will be taking in college.

[pirateer]

I don't understand the third one being true because its saying you "must" have not eaten spinach, but thats not true because as you said there are other ways to get strong besides spinach. So saying that you "must" have not eaten it just seems wrong because although it is a possibility that you didn't eat spinach, you could have also just drank milk or lifted weights.

[MrHimynameisbob]

What doesnt kill you makes you stronger. Right?

[sonalipersaud]

Sorry I don't understand why the 3rd sentence is true. Can't not getting stronger be for other reasons?

[patrick]

what course is this video a part of? LSAT?

[michaelcortez]

Wth sal are you doing lsat prep because that would be extremely helpful, given I'm studying for the test

[timothymiceli]

Where did the practice exercises for this go on Khan Academy?

[Kalernor]

Can anybody please explain to me how "if p, then q" is logically equivalent to "q unless ~p" ?
Feel free to use truth tables to whatever method that would help in explaining

[akshitapandey]

The biggest nightmare of Sal
I am running out of

[benkemp]

Third is also false. I don’t have a technical explanation. It’s just my intuition.

[WhyNotMeRight]

Still trying to understand the purpose of this video. Not the reasoning. The purpose.

[lugger_man_]

why does this matter I'm never going to use this in life