Help a sister out (elementary logic question)

Okay, I’m taking my logic midterm today and I’m still confused on one part. Hope you guys can help me out.

The professor talked about universal and statistical generalizations in lecture. He then talked about Affirmative and Negative Universal generalizations as well as Affirmative and Negative Existential generalizations.

Here’s my problem. When testing for validity using the three rules:

  1. The middle term must be distributed exactly once. The middle term must be distributed in one of the premises and undistributed in the other premise. The middle term does not occur in the conclusion.

  2. No end term can be distributed exactly once. The S term can be distributed in the conclusion iff it is distributed in a premise; the same is true for the P term.

  3. The number of negative conclusions must equal the number of negative premises. That is to say, there can be a negative conclusion iff there is exactly one negative premise.
    the book says that in universal generalizations the subject is distributed and in negative generalizations the predicate is distributed. The professor agrees with this. I can’t get my mind around what, exactly, a negative generalization is, except that it applies to these generalizations. What am I to do with Negative Universal generalizations? Are S & P both distibuted in this case? Is that even possible (to have S&P both distibuted)?

I guess I need clarification on what they mean by negative. I suspect they mean somethig different than negative universal and negative existential when using the term negative, but I could be wrong, and that would no bode well for this midterm today. Help! Please…

No logic masters in the house?

This’d go better in GQ.

My background’s in formal logic, and I’ve never heard of some of this stuff. Is this a symbolic logic class?


No, this is the precursor to symbolic logic, elementary logic. Aristotalian(sp?) logic. You’re probably right thouhg, it would go better in GQ. Thanks for the response though, ultrafilter. Sorry to confuse you Rhaeven.

The mid-term is over, and I think I did alright (probably a B anyway), but I’m still unclear on this. Can a moderator maybe move this to GQ so I can get an answer? Please and thank you. :slight_smile:

Off to GQ.

Thank you, UncleBeer, for your prompt response to my request.

Maybe I’ll be lucky enough to get an answer. It seems I’m speaking Greek even to people who are knowledgable in the subject, which makes me wonder just what kind of logic this professor is teaching us. :confused:

What book are you using?

From the “Grain of Salt Land”.

In a negative generalization S(subject) would be disjointed from P(predicate). Such as in “No S are P” or “No S is P”.
I understand it as S and P both can be distributed but in the statement they are not the same.
The opposite catagorical statement would be “All S are P”
Both are distributed and both are the same thing.
Example of Negative universal; “No Yugos are fast”
Affirmative Universal; “All Yugos are fast”

Try these cites
Categorical Props.


Any help from those who were actually schooled in this matter may be of some help, I have not been.

Sorry, in the above post the Affirmative predicate in not distributed.

Here is why.

I found this as well.

"If, however, both predicate and subject are distributed, the proposition thus constituted is contrary to truth; no affirmation will, under such circumstances, be true. The proposition ‘every man is every animal’ is an example of this type. "
— However, the negative universal can have the S and P distributed.


Again, coming from a lay-person.

Excellent whuckfistle! That does help. So they can both be distributed. I’ll check out the sites you linked to to see if that a rule that is always applicable.

And RM Mentock, the main text we are using is Introduction to Logic and Critical Thinking by Merrilee Salmon. We are also using How to Think About Wierd Things: Critical Thinking for a New Age by Theodore Schick, Jr. and Lewis Vaugn. I like that I get a lot of technical knowledge from Salmon, and find that Schick & Vaugn have written their book as much for entertainment as for instruction–it does both quite well.

Thank you both for your replies.