This page was included in order to give an overview of valid forms of classical logic (which I prefer over Symbolic Logic), so if I slip into the shorthand of describing an argument as AAA or EIO, the reader will have this page to use as reference.

It's important to remember that just because an argument doesn't have a valid form doesn't mean the conclusion is

*false*. It means that the conclusion is*unproven*from the argument ("You can't get there from here.")
For a deeper view of logic, I highly recommend Dr. Peter Kreeft's

*Socratic Logic*.

__Valid Logical Forms__

A= All [A] is [B]

E= No [A] is [B]

I= Some [A] is [B]

O= Some [A] is not [B]

(and, no, I don't know why they chose AEIO instead of ABCD)

(and, no, I don't know why they chose AEIO instead of ABCD)

__Valid Syllogisms__

AAA, AEE, EIO, AII, AOO

Other forms of argument are invalid

__Valid Combinations of Premises__

AA, AE, AI, AO, EI

(You can reverse the order of these, for example, EA instead of AE, but EAE is the same as AEE. You

*can't*however use EEA as a valid form of argument)__The Requirements of Premises__

A valid argument must mention all the claims (A, B and C)
over the major and minor premises

For example:

·
All A is B

·
All B is C

·
Therefore All A is C

__Outline of the Valid forms of Argument__

So the only valid forms of argument are AAA, AEE, EIO, AII and AOO. Here are some examples of how they are structured:

AAA:

·
All A is B

·
All B is C

·
Therefore All A is C

AEE:

·
All A is B

·
No C is B

·
Therefore No C is A

EIO:

·
No A is B

·
Some A is C

·
Therefore Some C is not B

AII:

·
All A is B

·
Some C is A

·
Therefore Some B is C

AOO:

- All A is B
- Some C is not B
- Therefore Some C is not A

I have to ask about the Old McDonald form:

ReplyDeleteEI

EI

O

:D

DeleteAll kidding aside, I am not familiar with the AAA etc. forms, so thank you for this handy reference.

ReplyDeleteA good book on these forms (and logic in general) is Peter Kreeft's "Socratic Logic"

DeleteHere's a link if you're interested:

http://www.amazon.com/Socratic-Logic-Questions-Aristotelian-Principles/dp/1587318083

Thanks!

ReplyDelete