Categorical Syllogism Exercise

1
Categorical Syllogism Exercise
2
Identify major, minor, and middle terms, mood,
and figure

• All ozone molecules are good absorbers of UV
  light.
• All ozone molecules are things destroyed by
  chlorine.
• Therefore, some things destroyed by chlorine are
  good absorbers of UV light.

3

• Major term good absorbers of UV light
• Minor term things destroyed by chlorine
• Middle term ozone molecule
• Mood-figure AAI-3 invalid under Boolean
  standpoint, valid under Aristotelian one.

4
Construct a syllogism

• An EIO-2 syllogism with these terms major fans
  of Twins minor lovers of good music middle
  persons capable of independent thinking.

5

• No fans of Twins are persons capable of
  independent thinking.
• Some lovers of good music are persons capable of
  independent thinking.
• Some lovers of good music are not fans of Twins.

6
Use Venn diagrams to determine validity

• No AIDS victims are persons who pose an immediate
  threat to the lives of others.
• Some kindergarten children are AIDS victims.
• Therefore, some kindergarten children are not
  persons who pose an immediate threat to the lives
  of others.

7

• No concertos are symphonies.
• No symphonies are string quartets.
• Therefore, no string quartets are concertos.

8
Use Venn diagrams to see whether a valid
conclusion can be drawn from premises

• Some P are not M.
• All M are S.

9

• Some P are not M.
• All S are M.

10

• All P are M.
• All S are M.

11
Reduce the number of terms and use Venn diagram
to test validity

• No cases of AIDS are infections easily curable by
  drugs, since all diseases that infect the brain
  are infections not easily curable by drugs, and
  all diseases that do not infect the brain are
  cases other than AIDS.

12

• All D are non-I. (obversion) No
  D are I.
• All non-D are non-C. (contraposition) All C are
  D.
• No C are I.
  No C are I.
• Valid

13
Translate into standard form and use Venn diagram
to test validity

• Wherever icebergs are present, threats to
  shipping exist. Icebergs are not present in the
  South Pacific. Hence, there are no threats to
  shipping in the South Pacific.

14
Supply the missing proposition in the enthymeme
and convert it into a valid argument

• Any drastic decline in animal life is cause for
  alarm, and the current decline in frogs and toads
  is drastic.

15

• All of the operas except Mozarts were well
  performed, and Carmen was not written by Mozart.

16

• Wherever water exists, human life can be
  sustained, and water exists on the moon.

17
Convert the enthymemes into the standard forms of
valid syllogisms

• Committing suicide is a right. If a person
  decides that life is impossible, it is his or her
  right to end it.

18

• Encouraging toy-gun play gives children a clear
  message that the best way to deal with
  frustration and conflict is with a gun. Is this
  the message we want to be sending our kids?

19
Rewrite the sorites in standard form, supply the
intermediate conclusions and test for validity

• No S are M.
• All F are S.
• Some M are H.
• All E are F.
• Some H are not E.

20

• All M are non-P.
• Some M are S.
• All K are P.
• Some non-K are not non-S.

21
Rewrite the sorites in standard form, use Venn
diagram to prove validity

• Some college students purchase their term papers.
• Any cheat is expelled from college.
• No one will achieve his career goals if he/she is
  expelled.
• No one who purchase term papers is other than a
  cheat.
• Therefore, some college students will not achieve
  their career goals.

22

• Creation science does not favor the teaching of
  evolution.
• Nothing should be taught that frustrates the
  understanding of life.
• Whatever opposes the teaching of evolution
  impedes the learning of biology.
• Anything that enhances the understanding of life
  fosters the learning of biology.
• Therefore, creation science should not be taught.

23

• All writers who understand human nature are
  clever.
• No one is a true poet unless he can stir the
  hearts of men.
• Shakespeare wrote Hamlet.
• No writer who does not understand human nature
  can stir the hearts of men.
• None but a true poet could have written Hamlet.
• Shakespeare was clever.