PART I. (10 points, 2 points each) Determine which of the following passages are arguments. For those that are arguments, underline the conclusion of the argument. If a passage is a non-argument, say what kind of non-argument. Choose from the types of non-arguments described in section 1.2.


1.      Language is the incarnation of the mentality of the race which fashioned it. Every phrase and word embodies some habitual idea of a set of particular communities of men and women as they ploughed their fields, tended their homes, and built their cities. For this reason, precise translations of words and phrases from one language to another aren’t really possible.





2.  Abraham Lincoln died because John Wilkes Booth shot him with a pistol.





2.      Experience has shown that international cooperation to resolve global issues is possible, but states must recognize their responsibilities toward one another if they are to live together peacefully.





3.      Neither the chameleon nor the hypocrite can have self-respect. Self-respect requires personal integrity: abiding convictions, and action in agreement with convictions. Lacking firm convictions and abiding affections, the chameleon-like person tailors his or her views to fit changing circumstances. The hypocrite, in contrast, has lasting convictions and emotional bonds, but betrays those convictions and bonds in his or her conduct.





4.      Since the Vietnam War, America has been reluctant to get militarily involved except in situations where success was virtually certain.






PART II. (30 points, 6 points each) Determine whether the following arguments are inductive or deductive. If inductive, determine whether strong or weak. If deductive, determine whether valid or invalid. Explain your answers. HINT: You can often use the general type of argumentation — argument from analogy, generalization from a sample, causal argument, argument from signs, argument from authority, categorical syllogism, disjunctive syllogism, hypothetical syllogism, etc. — to help determine whether the argument is inductive or deductive.  See the following examples.



Question: “Most Americans currently live in Nevada.  Aretha Franklin (the famous singer) is an American. So, it is likely Aretha Franklin currently lives in Nevada.”


Inductive or Deductive? (You write) Inductive

Why? The arguer claims that the premises, if true, make the conclusion likely.  This is the defining characteristic of inductive arguments.


Logically correct? (I.e., if deductive, valid or invalid; if inductive, strong or weak – choose one)?  (You write) Strong

Why/ why not?  In this argument, the conclusion really would be likely if the premises were true.  The first premise (“Most Americans live in Nevada”) is clearly false, however, so the argument cannot be cogent.



Question: “All Americans currently live either in Nevada or California.  The famous American singer Aretha Franklin does not live in Nevada. So, Aretha Franklin currently lives in California.”


Inductive or Deductive? (You write) deductive

Why? The argument is a disjunctive syllogism – one of the forms that signifies deduction.


Logically correct? (valid or invalid, strong or weak – choose one)?  (You write) valid

Why/ why not?  Disjunctive syllogism is a valid form so all its substitution instances are valid arguments  The first premise (“All Americans currently live either in Nevada or California”) is clearly false, however, so the argument cannot be sound.



1.   This morning there were drops of oil on the pavement, right under the hood of Tom’s car. The drops were not there last night. Probably Tom’s car has begun to leak oil.


      Inductive or deductive?






      Logically correct (valid or invalid, strong or weak)?

      Why / why not?





2.   All mammals are cats.  All cats are animals.  So all mammals are animals.


      Inductive or deductive?





      Logically correct?

      Why / why not?





3.   A porpoise is similar to a human being.  It has lungs rather than gills. It is warm-blooded rather than cold-blooded.  And porpoises nurse their young with milk. Therefore, porpoises, like humans, are probably capable of speaking languages.


      Inductive or deductive?

      Why? (HINT: What type of argument is this?)



      Logically correct?

      Why / why not?





4.  The headline of today’s New York Times says that yesterday a hurricane struck Indonesia. Therefore, yesterday a hurricane struck Indonesia.


      Inductive or deductive?





      Logically correct?

      Why / why not?




5.   If beings from other planets have visited us and there is an official government cover-up, then the government would, of course, deny any knowledge of these alien visits. The government does deny knowledge of these alien visits. Therefore, creatures from other planets must have visited us and there is an official government cover-up. 


      Inductive or deductive?






      Logically correct?

      Why / why not?





PART III. (20 points, 10 points each) Use the counterexample method to prove the following arguments invalid.


1.   All planets are round, so the earth must be a planet, since the earth is round.










2.         If Arnold is married to Becky, then Arnold is not a bachelor. Arnold is not married to Becky. Therefore, Arnold is a bachelor.












PART IV. Multiple choice. (12 points, 2 points each)


1.   Which of the following is a sufficient condition for winning a football game?

A.   at the end of the game, having earned three points more than the other team

B.   avoiding injury during play

C.   having a defense that is at least as good as your offense

D.   showing up to play the game

E.      getting at least one touchdown


2.   Which of the following is a necessary condition for passing a test?

A.   studying the material the night before

B.   showing up to take the test

C.   bringing “crib notes” to the test

D.   participating in a study group

E.   earning a score of at least C+


3.  Which of the following never occurs in an invalid argument?

A.   true premises, true conclusion

B.   true premises, false conclusion

C.   false premises, false conclusion

D.   false premises, true conclusion

E.   invalid arguments can have any of the above combinations


4.   Which of the following statements is false?

A.   A sound argument may have a false premise.

B.   A sound argument must be valid.

C.   A sound argument cannot be an argument from analogy.

      D.   A sound argument cannot be strong.

E.   A sound argument cannot have a false conclusion.


5.  Which of the following is not a premise indicator?

A.   implies that

B.   since

C.   for the reason that

D.   because

E.   for


6.  Which of the following sentences is a statement?

A.   No dogs are collies.

B.   How many dogs do you own?

C.   Get your dog off my lawn!

D.   Let’s get a dog.


7.  If a deductive argument has a true conclusion, then we know the argument is

A.   sound

B.   valid

C.   strong

D.   cogent

E.   none of the above


8.  If a deductive argument has a false premise, what do we know about the argument?

A.   It’s invalid

B.   It’s weak

C.   It’s unsound

D.   The conclusion is false

E.   None of the above






PART V. True or false? (28 points, 2 points each)


1. _____ If a valid argument has only true premises, then it must have a true conclusion.


2. _____ Every invalid argument is unsound.


3. _____ If an argument is not cogent, one or more of its premises must be false.


4. _____ The inferential (logical) claim in an inductive argument is that it is impossible for

               the premises to be true and the conclusion false.


5. _____ Some arguments are false.


6. _____ Every valid argument with a true conclusion is sound.


7. _____ Every valid argument with a false conclusion has at least one false premise.


8. _____ The following argument is an argument from analogy: “According to Flew’s     

              Dictionary of Philosophy, the British philosopher Bertrand Russell died in 1970.  So  

              Bertrand Russell died in 1970.”


9. _____ A weak argument is one in which an arguer claims a conclusion is likely if some

              premises are true, and the arguer’s claim is incorrect: i.e., the conclusion

              really isn’t likely if those premises are true.


10. ____ The following argument is cogent: “Most humans fear death.  Woody Allen (a real

               living human) is a human.  Therefore Woody Allen fears death.”


11. ____ It is possible for a cogent argument to have a false conclusion.


12. ____ A statement is the kind of sentence that can have a truth value.


13. ____ The following inductive argument is weak: “There is intelligent life on all the

              following planets: Mercury, Venus, Earth, Jupiter, Saturn, Uranus, Neptune..So it’s

              likely there is intelligent life on Mars.”


14. ____ A conditional statement asserts that the consequent is necessary for the antecedent.

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