4.4 Conversion, Obversion, and Contraposition

Professor Thorsby explains the logical operations of conversion, obversion, and contraposition

[swirleisme]

Ok, so wrap up:

Conversion - only works on E and I statements, switch Subject and Predicate terms
No S are P. --> No P are S. Some S are P. --> Some P are S.

Obversion - works on ALL statements, change the quality (e.g. "all, " "no") and replace the Predicate with it's compliment ("non-X")
All S are P. --> No S are non-P. Some S are P. --> Some S are non-P.

Contraposition - only works on A and O statements, switch Subject and Predicate terms, and replace BOTH with their compliment.
All S are P. --> All non-P are non-S. No S are non-P. --> No P are non-S.

[RomelleSpychala]

Thanks so much for your videos! I'm away from my class (out on 3 weeks surgery leave) and you helped me keep up with my lessons. I couldn't have done it without you! Great teaching.. thanks.

[hana_fa]

Thank you for helping me and my friend on our test! You're an amazing professor. Don't stop making videos :)

[jalisaross]

Thank you so much for these videos. We are following this book and you helping me get through this class. I appriciate it! Many thank yous!

[mcallisterwilliams]

Your videos are SUPER helpful. I am taking a Philosophy class online, and you have helped decipher Hurley's text tremendously. THANK YOU!!!

[MegRickman]

Super helpful! Our teacher in college doesn’t even attempt to teach this to us. We have to learn in on our own. Your videos are key to my understanding as I have dyscalculia and the book and words are difficult to comprehend

[bananacreamchip]

Your review in the beginning really clicked everything about this topic. Thanks!!

[elghunk]

All thanks for this video are expressions of gratitude. Now I will try to contraobvert this into a contradictory posision. 

Seriously, Very helpful video for the average person trying to grasp some logic!

[agreewme]

This was awesome and so helpful. Thank you so much! I'm taking an online logic course (if you can believe that) and I'm so lost most of the time. You made it a lot more understandable for me. Thanks again!

[meghnasingh]

Idk how to say thanks to you sir! You are my saviour, I thought I wouldn't be able to understand it

[abigailperks]

I have a test tomorrow and this helped me get a better understanding ‘cause, being in 7th grade My mind will wander! So thank you for this helpful lecture!

[mariagodinez]

You help me understand my logic course so much more! Thanks! Appreciate the videos. So clear and simple:)

[kendineiyibakece]

Thank you for this great video. İt's very useful. Greetings from Turkey

[arushi]

These videos are such a huge help. Thank you!! I feel like I am gonna ace it. Yay :)

[astridvig]

Hi! Thank you so MUCH! This is the first video I saw and it's so easy to understand what conversion, obversion and contraposition means and in what cases they must be used. Thanks for the information and I'm gonna see your channel. :D

[dalvishyu]

thank you so much for your help! my professor talks so fast n hard to understand...this helps me getting through the semester!!!

[cosmosojoto]

so clear and understandably and all your online lectures are interesting keep up

[noobbsaiboot]

thank you soo much...you just thought me a week's work in 30mins

[Charinaki]

I learned a lot from this video more than from my professor. Thank you so much sir for explaining every step to get full contraposition. :)

[brightbIade]

Thanks so much for this sir. Really helped me a lot