INTRODUCTION TO LOGIC
COMPREHENSIVE EXAM SCRIPT VERIFIED
QUESTIONS AND SOLUTIONS GRADED
APLUS
●● It is usually cloudy when it rains. Somewhere it is raining now, thus
that place is cloudy now.
Answer: strong, cogent, inductive
●● Some pigs have wings. All winged things sing. Thus some pigs sing.
Answer: valid, unsound, deductive
●● No theocracies are true democracies. No secular governments are
theocracies. Thus, some secular governments are true democracies.
Answer: invalid, unsound, deductive
●● If a youth gets the driver's license, then they want to use the family
car. My daughter want to use the family car, therefore she must have her
driver's lisence.
Answer: invalid, unsound, deductive
●● Tom's car has a flat tire. Someone must have slashed it with a knife.
Answer: weak, uncogent, inductive
,●● Morgan Mayfield gives a number of reasons why we should turn off
our cell phones during class. It appears that Mayfield is one of those
Luddites who are opposed to technology altogether. No computers, no
iPods, no Palm Pilots--that's what Mayfield wants. But that's just
ridiculous. It's clear that Mayfield is wrong.
Answer: Straw man
●● Congressman Baxter, I know you will want to support our
application to clear-cut the old growth timber in the Great Northern
forest. After all, surely you don't want the media to find out about that
affair you've been having with a certain Capitol Hill intern.
Answer: Appeal to force.
●● There is a lot of talk these days about the need for greater fuel
economy in SUVs. But today's SUV's are really beautiful. The Lexus LS
450 has clean lines, supple leather, and polished hardwood. The Lincoln
Navigator features beautiful paint and the feel of strength and security.
And the Mercury Mariner has wonderful styling and a great sound
system. Who could ask for anything more?
Answer: Red herring.
●● The war in Iraq is justified beyond any question. America was
founded in the spirit of freedom and self-determination, and it finds its
destiny in liberating the victims of tyranny wherever they languish!
America is a beacon of hope for the oppressed, a refuge for the
,downtrodden, a shining star of freedom for the whole world! The hand
of the Almighty points the way! Every true patriot will heed the clarion
call of freedom for all humankind!
Answer: Appeal to the people.
●● Judge, surely I'm not obligated to pay that $400,000 in back taxes. If
you were to decide against me, it would really put a crimp in my
finances. I wouldn't be able to afford that new Rolls Royce, and my
social status in our upscale neighborhood will drop like a rock.
Answer: Appeal to pity.
●● Floyd Conway has given us his reasons for unrestricted logging in
our national forests. But it's obvious why he says these things. Floyd is a
lumberjack, and he just wants to ensure that he'll have a job in the years
ahead.
Answer: Argument against the person, circumstancial.
●● The idea that fast food is unhealthy is a lot of hooey. Why, 90% of
America eats fast food.
Answer: Appeal to the people.
●● The Second Amendment to the Constitution guarantees everyone the
right to bear arms. Therefore it should be legal for those undercover Al
Qaeda members to buy a carload of surface-to-air missiles.
Answer: Accident.
, ●● Ed Jackson Ed Jackson argues that the war in Iraq is immoral. But
look who's talking! Before his recent discharge, Jackson was
participating in the very war he now condemns. Obviously his
arguments can't be trusted.
Answer: You too. (tu quoque)
●● Katie has been squabbling with her fiancé about the details of their
wedding. Thus, it would be a good idea for her to hire somebody to beat
him up.
Answer: Missing the point.
●● The former Governor believes that aliens have landed in the Arizona
desert, so aliens must have landed in the Arizona desert.
Answer: Appeal to Unqualified Authority
●● The F.B.I. investigation was never able to establish that Smith was
not at the scene of the crime on the night of June 25th, so we may safely
conclude that he was there.
Answer: Appeal to ignorance
●● It rained on my birthday this year and it rained on my birthday last
year. Therefore, it always rains on my birthday.
Answer: Hasty Generalization
COMPREHENSIVE EXAM SCRIPT VERIFIED
QUESTIONS AND SOLUTIONS GRADED
APLUS
●● It is usually cloudy when it rains. Somewhere it is raining now, thus
that place is cloudy now.
Answer: strong, cogent, inductive
●● Some pigs have wings. All winged things sing. Thus some pigs sing.
Answer: valid, unsound, deductive
●● No theocracies are true democracies. No secular governments are
theocracies. Thus, some secular governments are true democracies.
Answer: invalid, unsound, deductive
●● If a youth gets the driver's license, then they want to use the family
car. My daughter want to use the family car, therefore she must have her
driver's lisence.
Answer: invalid, unsound, deductive
●● Tom's car has a flat tire. Someone must have slashed it with a knife.
Answer: weak, uncogent, inductive
,●● Morgan Mayfield gives a number of reasons why we should turn off
our cell phones during class. It appears that Mayfield is one of those
Luddites who are opposed to technology altogether. No computers, no
iPods, no Palm Pilots--that's what Mayfield wants. But that's just
ridiculous. It's clear that Mayfield is wrong.
Answer: Straw man
●● Congressman Baxter, I know you will want to support our
application to clear-cut the old growth timber in the Great Northern
forest. After all, surely you don't want the media to find out about that
affair you've been having with a certain Capitol Hill intern.
Answer: Appeal to force.
●● There is a lot of talk these days about the need for greater fuel
economy in SUVs. But today's SUV's are really beautiful. The Lexus LS
450 has clean lines, supple leather, and polished hardwood. The Lincoln
Navigator features beautiful paint and the feel of strength and security.
And the Mercury Mariner has wonderful styling and a great sound
system. Who could ask for anything more?
Answer: Red herring.
●● The war in Iraq is justified beyond any question. America was
founded in the spirit of freedom and self-determination, and it finds its
destiny in liberating the victims of tyranny wherever they languish!
America is a beacon of hope for the oppressed, a refuge for the
,downtrodden, a shining star of freedom for the whole world! The hand
of the Almighty points the way! Every true patriot will heed the clarion
call of freedom for all humankind!
Answer: Appeal to the people.
●● Judge, surely I'm not obligated to pay that $400,000 in back taxes. If
you were to decide against me, it would really put a crimp in my
finances. I wouldn't be able to afford that new Rolls Royce, and my
social status in our upscale neighborhood will drop like a rock.
Answer: Appeal to pity.
●● Floyd Conway has given us his reasons for unrestricted logging in
our national forests. But it's obvious why he says these things. Floyd is a
lumberjack, and he just wants to ensure that he'll have a job in the years
ahead.
Answer: Argument against the person, circumstancial.
●● The idea that fast food is unhealthy is a lot of hooey. Why, 90% of
America eats fast food.
Answer: Appeal to the people.
●● The Second Amendment to the Constitution guarantees everyone the
right to bear arms. Therefore it should be legal for those undercover Al
Qaeda members to buy a carload of surface-to-air missiles.
Answer: Accident.
, ●● Ed Jackson Ed Jackson argues that the war in Iraq is immoral. But
look who's talking! Before his recent discharge, Jackson was
participating in the very war he now condemns. Obviously his
arguments can't be trusted.
Answer: You too. (tu quoque)
●● Katie has been squabbling with her fiancé about the details of their
wedding. Thus, it would be a good idea for her to hire somebody to beat
him up.
Answer: Missing the point.
●● The former Governor believes that aliens have landed in the Arizona
desert, so aliens must have landed in the Arizona desert.
Answer: Appeal to Unqualified Authority
●● The F.B.I. investigation was never able to establish that Smith was
not at the scene of the crime on the night of June 25th, so we may safely
conclude that he was there.
Answer: Appeal to ignorance
●● It rained on my birthday this year and it rained on my birthday last
year. Therefore, it always rains on my birthday.
Answer: Hasty Generalization
