PHIL 105 Unit 3 UPDATED ACTUAL Exam
Questions and CORRECT Answers
Deductive validity comes in degrees. - CORRECT ANSWER - False. An argument is
either valid or not valid. It cannot be partly valid or have a degree of validity. The reason is that
deductive validity depends on possibility, and it is either possible or not possible (but not partly
possible) that the premises are true when the conclusion is false.
Inductive strength is not defeasible. - CORRECT ANSWER - False. A standard is
defeasible if adding further premises can turn an argument that meets the standard into an
argument that does not meet the standard. Adding further premises can turn an argument that is
very strong into an argument that is very weak. For example, the argument "The sun has come up
every day for thousands of years, so it will probably come up tomorrow" is very strong, but the
same argument becomes very weak if we add the new premise that a meteor will destroy the
earth this afternoon, because then it is unlikely that the sun will come up tomorrow. Thus,
inductive strength is defeasible.
Arguments that generalize from samples are: - CORRECT ANSWER - inductive.
Arguments that generalize from samples to a whole class were one of the kinds of inductive
argument. What makes them inductive is that they are not intended to be valid, their strength
varies in degrees, and they are defeasible.
An argument that generalizes from a sample to a whole class is stronger (other things being
equal) when - CORRECT ANSWER - the sample is larger.
When the sample is too small, the argument commits the fallacy of hasty generalization. A larger
sample helps the argument avoid this fallacy, so it makes the argument stronger. In contrast, false
premises and a biased sample make the argument weaker (instead of stronger) than when the
premises are true or the sample is unbiased.
Specify the main problem with the following generalization from a sample. There might be more
than one problem, but indicate the most important one.
,This Apple computer worked reliably for five years, so computers made by Apple are very
reliable. - CORRECT ANSWER - The sample is too small.
A sample of one is sometimes big enough for a generalization, but only when we can assume
uniformity in relevant respects throughout the sample. That assumption is questionable here.
Apple makes many different kinds of computers, so some might be reliable while others are not.
Moreover, even if 50 percent of Apple computers break down, the computer mentioned in the
premise might be one of the other 50 percent that does not break down. Because there might be
such variation in reliability, this sample is too small. Of course, it still might be true that Apple
computers are reliable, but this one case does not provide strong evidence for that conclusion.
An argument of the form "X percent of Fs are Gs, a is an F, so a is probably a G" is - CORRECT
ANSWER - defeasible.
This argument is not valid, because it is possible for its premises to be true when its conclusion is
false. It is also not a syllogism, because its premises and conclusion are not in the form of
categorical propositions (A,E,I,O). But it is defeasible because adding further premises can turn a
strong argument of this form into a weak argument of this form. For example, this argument
would become very weak if we added the premise that a is an F* for some F* where no F*s are
G.
Consider this argument: 90 percent of Germans like sausage, and Fritz is a German, so Fritz
probably likes sausage.
Would this argument be stronger or weaker if we added the information that only 20 percent of
Germans who are Muslims like sausage, and Fritz is a Muslim? - CORRECT ANSWER -
weaker.
The class "German Muslims" is a conflicting reference class that undermines the strength of the
argument.
If two explanations are equal in all other respects, then - CORRECT ANSWER - the more
conservative explanation is better.
Conservativeness is a standard explanatory virtue, so it makes explanations better, other things
being equal.
,Indicate which explanatory virtue is the main one that is lacking from this explanation: The cake
did not come out right, because every one of the ingredients we used was wrong. - CORRECT
ANSWER - modesty.
You do not need to claim that ALL of the ingredients were wrong in order to explain why the
cake did not come out right. It would be enough to claim that we used at least some essential
wrong ingredients. This explanation is falsifiable (because we can find out that we used SOME
of the right ingredients), conservative (because it is compatible with the common observation
that using the wrong ingredients can ruin cooking), powerful (because many other cooking
failures can be explained by using the wrong ingredients), and deep (because it does not raise
new explanatory questions, assuming that we used the wrong ingredients by mistake). Notice
that this explanation does not raise the question of WHICH ingredients were wrong, because it
says that they ALL were.
Consider this argument from analogy: I have visited many public gardens, and I almost always
enjoyed walking in them. I just moved to a new town with a public garden. I have not visited it
yet, but I know that it is similar in many ways to other public gardens that I have visited. So I
will probably enjoy walking in the new public garden as well.
Would this argument from analogy become stronger, weaker, or neither if we added a premise
that the new public garden is a rock garden, but none of the gardens that I visited before were
rock gardens? - CORRECT ANSWER - weaker.
Whether the garden is a rock garden or a plant garden affects whether some people enjoy
walking there, so this difference between previous gardens and the new garden is relevant to
whether I will enjoy walking there. I might enjoy the rock garden even more than a plant garden,
because of the novelty, but I might not. This uncertainty means that the analogies between the
gardens give me less reason to believe that I will enjoy walking in the rock garden than if the
new garden were also a plant garden like the gardens that I enjoyed before.
Being a swan is - CORRECT ANSWER - sufficient but not necessary for being a bird.
Every swan is a bird, so being a swan is sufficient for being a bird. However, some things that
are not swans (such as geese) are still birds, so being a swan is not necessary for being a bird.
Imagine that you buy a new computer system with independent components including a new
desktop computer (with a CPU and a graphics card), new software, and a new monitor. You want
to play games on the new system, but it runs games very slowly. You assume that the keyboard
and mouse are not creating the problem; so, to figure out what is making the system run so
, slowly, you experiment with combinations of your old equipment with the new equipment. Here
are your experiments and results:
Experiment 1: New computer, new software, and new monitor — and it runs slowly.
Experiment 2: New computer, new software, and old monitor — and it runs fast.
Experiment 3: New computer, old software, and new monitor — and it runs slowly.
Experiment 4: New computer, old software, and old monitor — and it runs fast.
Experiment 5: Old computer, new software, and new monitor — and it runs fast.
Experiment 6: Old computer, new softwar - CORRECT ANSWER - Experiment 5.
Experiment 5 used the new monitor (X is present), and the system ran fast rather than slowly (Y
is absent), so Experiment 5 refutes the claim that, whenever a system includes the new monitor
(X is present), that system runs slowly (Y is present). Thus, Experiment 5 shows that the new
monitor fails the negative sufficient condition test, so the new monitor is not sufficient for
running slowly.
No other experiment had new monitor without running slowly, because the only other
experiments with the new monitor were 1, 3, and 7, and the system ran slowly in all of those
experiments. Thus, no other experiment shows that the new monitor is not sufficient for running
slowly.
Which experiment shows that the new computer is not necessary for the system to run slowly? -
CORRECT ANSWER - Experiment 7.
Experiment 7 used the old computer rather than the new computer (X is absent), and the system
ran slowly (Y is present), so Experiment 7 refutes the claim that, whenever a system does not
include the new computer (X is absent), that system does not run slowly (Y is absent). Thus,
Experiment 7 shows that the new computer fails the negative necessary condition test, so the new
computer is not necessary for running slowly.
No other experiment ran slowly without the new computer, because the only other experiments
without the new computer were Experiments 5, 6, and 8, and the system did not run slowly in
any of those experiments. Thus, no other experiment shows that the new computer is not
necessary for running slowly.
Questions and CORRECT Answers
Deductive validity comes in degrees. - CORRECT ANSWER - False. An argument is
either valid or not valid. It cannot be partly valid or have a degree of validity. The reason is that
deductive validity depends on possibility, and it is either possible or not possible (but not partly
possible) that the premises are true when the conclusion is false.
Inductive strength is not defeasible. - CORRECT ANSWER - False. A standard is
defeasible if adding further premises can turn an argument that meets the standard into an
argument that does not meet the standard. Adding further premises can turn an argument that is
very strong into an argument that is very weak. For example, the argument "The sun has come up
every day for thousands of years, so it will probably come up tomorrow" is very strong, but the
same argument becomes very weak if we add the new premise that a meteor will destroy the
earth this afternoon, because then it is unlikely that the sun will come up tomorrow. Thus,
inductive strength is defeasible.
Arguments that generalize from samples are: - CORRECT ANSWER - inductive.
Arguments that generalize from samples to a whole class were one of the kinds of inductive
argument. What makes them inductive is that they are not intended to be valid, their strength
varies in degrees, and they are defeasible.
An argument that generalizes from a sample to a whole class is stronger (other things being
equal) when - CORRECT ANSWER - the sample is larger.
When the sample is too small, the argument commits the fallacy of hasty generalization. A larger
sample helps the argument avoid this fallacy, so it makes the argument stronger. In contrast, false
premises and a biased sample make the argument weaker (instead of stronger) than when the
premises are true or the sample is unbiased.
Specify the main problem with the following generalization from a sample. There might be more
than one problem, but indicate the most important one.
,This Apple computer worked reliably for five years, so computers made by Apple are very
reliable. - CORRECT ANSWER - The sample is too small.
A sample of one is sometimes big enough for a generalization, but only when we can assume
uniformity in relevant respects throughout the sample. That assumption is questionable here.
Apple makes many different kinds of computers, so some might be reliable while others are not.
Moreover, even if 50 percent of Apple computers break down, the computer mentioned in the
premise might be one of the other 50 percent that does not break down. Because there might be
such variation in reliability, this sample is too small. Of course, it still might be true that Apple
computers are reliable, but this one case does not provide strong evidence for that conclusion.
An argument of the form "X percent of Fs are Gs, a is an F, so a is probably a G" is - CORRECT
ANSWER - defeasible.
This argument is not valid, because it is possible for its premises to be true when its conclusion is
false. It is also not a syllogism, because its premises and conclusion are not in the form of
categorical propositions (A,E,I,O). But it is defeasible because adding further premises can turn a
strong argument of this form into a weak argument of this form. For example, this argument
would become very weak if we added the premise that a is an F* for some F* where no F*s are
G.
Consider this argument: 90 percent of Germans like sausage, and Fritz is a German, so Fritz
probably likes sausage.
Would this argument be stronger or weaker if we added the information that only 20 percent of
Germans who are Muslims like sausage, and Fritz is a Muslim? - CORRECT ANSWER -
weaker.
The class "German Muslims" is a conflicting reference class that undermines the strength of the
argument.
If two explanations are equal in all other respects, then - CORRECT ANSWER - the more
conservative explanation is better.
Conservativeness is a standard explanatory virtue, so it makes explanations better, other things
being equal.
,Indicate which explanatory virtue is the main one that is lacking from this explanation: The cake
did not come out right, because every one of the ingredients we used was wrong. - CORRECT
ANSWER - modesty.
You do not need to claim that ALL of the ingredients were wrong in order to explain why the
cake did not come out right. It would be enough to claim that we used at least some essential
wrong ingredients. This explanation is falsifiable (because we can find out that we used SOME
of the right ingredients), conservative (because it is compatible with the common observation
that using the wrong ingredients can ruin cooking), powerful (because many other cooking
failures can be explained by using the wrong ingredients), and deep (because it does not raise
new explanatory questions, assuming that we used the wrong ingredients by mistake). Notice
that this explanation does not raise the question of WHICH ingredients were wrong, because it
says that they ALL were.
Consider this argument from analogy: I have visited many public gardens, and I almost always
enjoyed walking in them. I just moved to a new town with a public garden. I have not visited it
yet, but I know that it is similar in many ways to other public gardens that I have visited. So I
will probably enjoy walking in the new public garden as well.
Would this argument from analogy become stronger, weaker, or neither if we added a premise
that the new public garden is a rock garden, but none of the gardens that I visited before were
rock gardens? - CORRECT ANSWER - weaker.
Whether the garden is a rock garden or a plant garden affects whether some people enjoy
walking there, so this difference between previous gardens and the new garden is relevant to
whether I will enjoy walking there. I might enjoy the rock garden even more than a plant garden,
because of the novelty, but I might not. This uncertainty means that the analogies between the
gardens give me less reason to believe that I will enjoy walking in the rock garden than if the
new garden were also a plant garden like the gardens that I enjoyed before.
Being a swan is - CORRECT ANSWER - sufficient but not necessary for being a bird.
Every swan is a bird, so being a swan is sufficient for being a bird. However, some things that
are not swans (such as geese) are still birds, so being a swan is not necessary for being a bird.
Imagine that you buy a new computer system with independent components including a new
desktop computer (with a CPU and a graphics card), new software, and a new monitor. You want
to play games on the new system, but it runs games very slowly. You assume that the keyboard
and mouse are not creating the problem; so, to figure out what is making the system run so
, slowly, you experiment with combinations of your old equipment with the new equipment. Here
are your experiments and results:
Experiment 1: New computer, new software, and new monitor — and it runs slowly.
Experiment 2: New computer, new software, and old monitor — and it runs fast.
Experiment 3: New computer, old software, and new monitor — and it runs slowly.
Experiment 4: New computer, old software, and old monitor — and it runs fast.
Experiment 5: Old computer, new software, and new monitor — and it runs fast.
Experiment 6: Old computer, new softwar - CORRECT ANSWER - Experiment 5.
Experiment 5 used the new monitor (X is present), and the system ran fast rather than slowly (Y
is absent), so Experiment 5 refutes the claim that, whenever a system includes the new monitor
(X is present), that system runs slowly (Y is present). Thus, Experiment 5 shows that the new
monitor fails the negative sufficient condition test, so the new monitor is not sufficient for
running slowly.
No other experiment had new monitor without running slowly, because the only other
experiments with the new monitor were 1, 3, and 7, and the system ran slowly in all of those
experiments. Thus, no other experiment shows that the new monitor is not sufficient for running
slowly.
Which experiment shows that the new computer is not necessary for the system to run slowly? -
CORRECT ANSWER - Experiment 7.
Experiment 7 used the old computer rather than the new computer (X is absent), and the system
ran slowly (Y is present), so Experiment 7 refutes the claim that, whenever a system does not
include the new computer (X is absent), that system does not run slowly (Y is absent). Thus,
Experiment 7 shows that the new computer fails the negative necessary condition test, so the new
computer is not necessary for running slowly.
No other experiment ran slowly without the new computer, because the only other experiments
without the new computer were Experiments 5, 6, and 8, and the system did not run slowly in
any of those experiments. Thus, no other experiment shows that the new computer is not
necessary for running slowly.
