5.3 Rules and Fallacies

Professor Thorsby briefly discusses what the 5 rules for valid Catgeorical Syllogisms are and how to use them to test for validity.

[gsarraf]

you made something extremely foreign and frustrating,   easy and understandable. Thank you for sharing. Wish I could have paid you tuition!

[nallecasio]

You have no idea how helpful your videos are

[MegRickman]

I wish you were my teacher. But your videos here are good substitute for my teacher. Thank you.

[johnny]

i had no idea about the rules of validity until now. We have a test tomorrow and i assure you, im a lot more confident now than before. my prof. just confuses me during class, nice to hear it again from someone else.

[ladycash]

Glad I found your videos. It took my frustration away.

[sarahgold]

This video was incredibly helpful. It made things crystal clear. Thank you!

[walterg]

thanks for the help Mark! really came in handy nailing my quiz with an A!

[adrianaleon]

Now I can understand everything. The book I think you are using is Logic by Hurley. I have a new version where chapter 2 is omitted, but anyways, a Logic book is boring. You make it feel very natural

[iyyappan_nathan]

Dear Sir, Thanks a lot for your lessons.

[gutplameri]

Thank you very  much for this awesome video.
One question.. What if the conclusion is an E statement? .. What is the fallacy for rule #2?

[yiomgateforknowledge]

Thanks professor you gave me solid idea for me

[manuelmanuel]

Is deductive syllogistic logic just set theory put into words?

[mariaqadir]

Your all videos r helpfull fr tysmmmm sirrrr💕😍😍 it shud be a dream of any student to gets tution of logic frm u 😍

[robobrain]

I prefer the Venn Diagrams more. The distribution rules mess me up.

[rexgregorlaylo]

thanks sir ! i have some weapons for tomorrow's finals...

[nathanhammer]

Couldn’t you say I statements distribute both ways in the same way you say Os distribute? Namely that not all S are not P and not all P are not S?

[Syllogist]

Why on earth did you declare the construction AAA-3 (24:35):
1. Al M are P
2. All M are S
- - - Therefore - - -
3. Are all S P - as invalid?

We carry out an elementary algebraic calculation (where M is the average term):
1. All M are P (MP)
2. All M are S (MS)
- - Calculation: ((MP*MS)/M = MPS/M = PS - - -
3. All S are P - This is the correct answer!
(All S are P because both are M).

The "rules 1-5" you mention are just an archaic hypothesis constructed before the advent of the Boole algebra.
There are other errors in your video, for example, instead of an erroneous output (29:10), "Some O are N" (Did you write the answer yourself and declared it wrong yourself? :-) should write "Some N are O", etc., etc.

More details:
3) 09-03. Расчёт силлогизмов модусов AEE, EАE, EAO, EEE… / РАЗГАДКА «Бермyдских треугoльников» ЛОГИКИ-3
/ Calculation of syllogisms of modes AEE, EАE, EAO, EEE...