FINAL EXAM PHIL 183 QUESTIONS
AND ALL CORRECT ANSWERS 2026.
what theories are and what it should take to be confident in them - Answer A theory is any
claim (or group of claims) that explains why we observe some of the things we do.
what it means for two claims to be probabilistically independent - Answer Two claims A and
B are probabilistically independent when P ( A ) = P( A | B ).
how the general conjunction & disjunction rules works what the planning fallacy is, and how it
relates to conjunction - Answer Conjunction rule: P( A and B ) = P( A ) × P( B | A ) Disjunction
rule: P( A or B ) = P( A ) + P( B ) − P( A and B ) One important lesson to take away is that, in
general, a claim gets less probable the more conjunctive it is. Even if each element of the claim
is itself quite probable, the conjunction may be improbable. This is one potential explanation for
the fact that we tend to systematically underestimate how long it will take to complete a project
involving many steps—a pitfall called the planning fallacy.
how we can use the updating procedure even when we don't have a statistical base rate to use
as a prior probability - Answer This is where the criteria of theory choice come in.
Coherence, Simplicity, and Breadth are the important criteria.
the three criteria of theory choice (coherence, simplicity, and breadth) and why they are
important - Answer The first criterion of theory choice is coherence. The more a theory fits
with what we know about the world, the more coherent it is with our background knowledge.
The second criterion of theory choice, simplicity, tells us that we should find theories more likely
the less complexity they add to our overall view of the world. When one theory can explain
more different kinds of observations than another, we say it has greater breadth.
how it is that we can get lots of evidence for a hypothesis, without that hypothesis being worthy
of belief - Answer It can have high evidential strength but is so crazy and impossible it would
be technically impossible to believe
how we can get evidence for a specific hypothesis while not getting evidence for a more general
hypothesis entailed by it (Fred & the lottery) - Answer In short, although we do get a lot of
evidence in favor of the hypothesis that Fred rigged the lottery, it was extremely unlikely to
begin with. So we should still think it's unlikely he rigged the lottery. In fact, learning that Fred
won has no effect at all on our confidence that someone rigged the lottery. (The probability that
the lottery was rigged is still one in a hundred.) We just know that if someone did, it was Fred.
why the best explanation is sometimes probably false - Answer "Inference to the best
explanation" or "IBE" is often described as having the following form:
, P1. H1 is the best explanation for E.
C1. So, H1 is probably true First, it fails to take into account how probabilities add up.
Second, the "best explanation" argument form forgets that there are often explanations that
haven't occurred to us at all.
how statistical generalization follows the updating rule, which means it requires prior
probabilities - Answer Inference to the best explanation is sometimes contrasted with
statistical reasoning, as though they were fundamentally different ways of responding to
evidence. But in fact, when they are done correctly, both are simply instances of updating on
evidence, and both must take into account the criteria of theory choice from the previous
section.
how different scientific disciplines are using the updating rule even if they formulate hypotheses
after getting evidence - Answer If the theory did not actually occur to us until after we got
the relevant evidence, the "prior probability" that we are assessing is not actually the degree of
confidence we had in that theory before getting the evidence. (We didn't have a degree of
confidence in the theory because it had not occurred to us!) Instead, it's an attempt to assess
the plausibility of that theory, taken in isolation from the evidence, using the same standards
that we use to evaluate theories prior to getting evidence.
why it's preferable to formulate our hypotheses before getting evidence, to avoid ad hoc
modification - Answer One way we can cheat is by modifying our theories to account for the
evidence, without properly acknowledging that this makes them more complex and therefore
less plausible than the original. This is a process known as ad hoc modification.
how we can get evidence against a general hypothesis while not getting evidence against a
more specific hypothesis that entails it (Galileo case) - Answer It's not uncommon for people
to refuse to acknowledge that they have gotten evidence against some theory, because they fall
back on a more specific version of their theory that predicts the evidence. But it's important to
realize that there is almost always a more complex and bizarre version of a theory that can fit
the evidence.
how judgments about probability and goodness of outcomes can support choices - Answer A
choice might have a possible outcome that is very good, but if that outcome is also very unlikely,
then it doesn't count very heavily in favor of the choice.
how to use decision trees to represent aspects of a decision - Answer The black square is the
way things are to begin with: we're faced with a decision between two options. Each circle
represents a choice we could make—maybe they are actions we can take, or things we can say,
or maybe one is the choice to do nothing at all. And the squares directly connected to that circle
represent possible outcomes of the choice.
AND ALL CORRECT ANSWERS 2026.
what theories are and what it should take to be confident in them - Answer A theory is any
claim (or group of claims) that explains why we observe some of the things we do.
what it means for two claims to be probabilistically independent - Answer Two claims A and
B are probabilistically independent when P ( A ) = P( A | B ).
how the general conjunction & disjunction rules works what the planning fallacy is, and how it
relates to conjunction - Answer Conjunction rule: P( A and B ) = P( A ) × P( B | A ) Disjunction
rule: P( A or B ) = P( A ) + P( B ) − P( A and B ) One important lesson to take away is that, in
general, a claim gets less probable the more conjunctive it is. Even if each element of the claim
is itself quite probable, the conjunction may be improbable. This is one potential explanation for
the fact that we tend to systematically underestimate how long it will take to complete a project
involving many steps—a pitfall called the planning fallacy.
how we can use the updating procedure even when we don't have a statistical base rate to use
as a prior probability - Answer This is where the criteria of theory choice come in.
Coherence, Simplicity, and Breadth are the important criteria.
the three criteria of theory choice (coherence, simplicity, and breadth) and why they are
important - Answer The first criterion of theory choice is coherence. The more a theory fits
with what we know about the world, the more coherent it is with our background knowledge.
The second criterion of theory choice, simplicity, tells us that we should find theories more likely
the less complexity they add to our overall view of the world. When one theory can explain
more different kinds of observations than another, we say it has greater breadth.
how it is that we can get lots of evidence for a hypothesis, without that hypothesis being worthy
of belief - Answer It can have high evidential strength but is so crazy and impossible it would
be technically impossible to believe
how we can get evidence for a specific hypothesis while not getting evidence for a more general
hypothesis entailed by it (Fred & the lottery) - Answer In short, although we do get a lot of
evidence in favor of the hypothesis that Fred rigged the lottery, it was extremely unlikely to
begin with. So we should still think it's unlikely he rigged the lottery. In fact, learning that Fred
won has no effect at all on our confidence that someone rigged the lottery. (The probability that
the lottery was rigged is still one in a hundred.) We just know that if someone did, it was Fred.
why the best explanation is sometimes probably false - Answer "Inference to the best
explanation" or "IBE" is often described as having the following form:
, P1. H1 is the best explanation for E.
C1. So, H1 is probably true First, it fails to take into account how probabilities add up.
Second, the "best explanation" argument form forgets that there are often explanations that
haven't occurred to us at all.
how statistical generalization follows the updating rule, which means it requires prior
probabilities - Answer Inference to the best explanation is sometimes contrasted with
statistical reasoning, as though they were fundamentally different ways of responding to
evidence. But in fact, when they are done correctly, both are simply instances of updating on
evidence, and both must take into account the criteria of theory choice from the previous
section.
how different scientific disciplines are using the updating rule even if they formulate hypotheses
after getting evidence - Answer If the theory did not actually occur to us until after we got
the relevant evidence, the "prior probability" that we are assessing is not actually the degree of
confidence we had in that theory before getting the evidence. (We didn't have a degree of
confidence in the theory because it had not occurred to us!) Instead, it's an attempt to assess
the plausibility of that theory, taken in isolation from the evidence, using the same standards
that we use to evaluate theories prior to getting evidence.
why it's preferable to formulate our hypotheses before getting evidence, to avoid ad hoc
modification - Answer One way we can cheat is by modifying our theories to account for the
evidence, without properly acknowledging that this makes them more complex and therefore
less plausible than the original. This is a process known as ad hoc modification.
how we can get evidence against a general hypothesis while not getting evidence against a
more specific hypothesis that entails it (Galileo case) - Answer It's not uncommon for people
to refuse to acknowledge that they have gotten evidence against some theory, because they fall
back on a more specific version of their theory that predicts the evidence. But it's important to
realize that there is almost always a more complex and bizarre version of a theory that can fit
the evidence.
how judgments about probability and goodness of outcomes can support choices - Answer A
choice might have a possible outcome that is very good, but if that outcome is also very unlikely,
then it doesn't count very heavily in favor of the choice.
how to use decision trees to represent aspects of a decision - Answer The black square is the
way things are to begin with: we're faced with a decision between two options. Each circle
represents a choice we could make—maybe they are actions we can take, or things we can say,
or maybe one is the choice to do nothing at all. And the squares directly connected to that circle
represent possible outcomes of the choice.
