Philosophy 102 – Reasoning and Critical Thinking

Categorical Syllogism Exercises:

I.  Determine the validity of the following argument schemes, and also identify its general form (AA, AC, DA, DC, or HS):

1.  All S are P.  No S are Q. /No S is Q.

2.  All S are P.  Some P are not Q. /Some S are not Q.

3.  All S are P.  No P are Q. /[?? -Identify what follows here!]

4.  No S are P.  Some S are not Q.  /Some P are not Q.

5.  No S are P.  Some P are not Q.  /Some S are not Q.

6.  No S are P.  No P are Q.  /All S are P.

7.  No S are P.  No S are Q.  /All P are Q.

8.  No S are P.  No P are Q.  /No S are Q.

9.  Some S are P.  Some S are not Q.  /Some P are not Q.

10.  All S are P.  Only Q are S.  /All S are Q.

11.  Only S are P.  All Q are P.  /All Q are S.

12.  Only S are P.  Only P are Q.  /Only S are Q. 

13.  All S are P.  [??].  /Some P are not Q.

14.  No S are P.  [??].  /No Q are S

15.* All S are P.  No P are Q.  /Some S are not Q.

16.   No non-S are P.  Some Q are not S.  /Some Q are P.

17.  No non-S are P.  Some Q are not S.  /Some Q are not P.

18.  No non-S are P.  All non-P are Q.   /[??]

19.  Only S are non-P.  Some P are Q.  /Some Q are not S 

20.  Only non-S are P.  Some P are not Q.  /[??]

*There’s something weird about this one.  Can you see what it is?

II.  Now determine the validity and form of the following arguments.  They may be either hypothetical or categorical.

1.  If there were life after death, at least a few people would have had apparitional encounters.  Since a few people have had apparitional encounters, there must be life after death.

2.  No boss works in a cubicle, while some bosses have pointy heads.  Thus some things that don’t work in a cubicle have pointy heads.

3.  Some directors of human resources are cats, and some cats purr when stroked.  So some directors of human resources purr when stroked.

4.  If one accepts the premise that only humans can speak, then some apes must really be humans, for some apes (like Kanzi and Koko) seem capable of linguistic expression.

5.  If Dilbert is to finish the project, he will have to move out of his cubicle.  But Dilbert will get to move out of his cubicle only if he strokes Catbert.  So for Dilbert to finish the project, he is going to have to stroke Catbert.

6.  I'll leave Las Vegas this summer only if I don't find a place with a pool.  You should therefore expect me to stay, since chances are looking pretty good that I'll be able to find a place with a pool.

 7.  Not all Phishheads wear sandals and hemp clothing.  So some Phisheads must not smell funny, since nobody who doesn't wear sandals and hemp clothing smells funny.

8.  Anyone who speaks in tongues does not speak to men but to God…But everyone who prophesies speaks to men for their strengthening, encouragement, and comfort.  (Paul, I Corinthians, 14:2-3)

9.  Gov. Jim Gibbons lashed out at critics Wednesday, saying in an interview that only a "moron" would accuse him of calling a special session as a political ploy…

Told of Gibbons' comments, Assembly Speaker Barbara Buckley, D-Las Vegas, reiterated Wednesday that the special session was "a stunt to divert attention from his personal life.” (LVRJ, 19 June 2008)

10.  Faced with the worst budget mess in Nevada history, state legislators can oppose a special session only if they have faith in the governor to handle the disaster.

So under the safe assumption that that is not the case, lawmakers can be against the session only because they either don’t want to legislate, the job they were hired to do, or are simply petrified they might have to legislate and thus lose the job they were hired to do. (Jon Ralston, Las Vegas Sun, 15 June, 2008)