epistemology

Question 1

three kinds of knowledge

Answer 1

Acquaintance - “I know Sally” - personally acquainted with someone, or a place, etc

Know how - I know how to ride a bike - I have a certain skill

Propositional knowledge - I know that 3+5=8, there are things that I stand in certain relation to

Question 2

propositions

Answer 2

Propositions state a possible way for things to be - they can be true or false depending on how the world is

eg. The proposition that grass is green states that grass is green

Question 3

abstract objects

Answer 3

propositions that are not spatiotemporal. In this respect, they are like numbers

Question 4

Propositions should be distinguished from sentences

Answer 4

Two distinct sentences may express the same proposition

Question 5

propositional attitudes

Answer 5

propositional knowledge is a relation that an agent stands in to propositions

eg. Belief: Yuko believes that Herman will arrive late

Fear: Xavier fears that Helen will arrive late

Wishes: Simone wishes that Samuel would arrive late

Question 6

that-clauses

Answer 6

In general attitude verbs that take that-clauses express propositional attitudes

Question 7

ambiguity in the types of knowledge

Answer 7

it can be unsure what knowledge is which - for example, proposition knowledge “I know Sally” - acquaintance knowledge, but also could be propositional knowledge that I know facts about Sally

Question 8

Knowledge as Belief

Answer 8

To know P is just to believe P

knowledge entails belief

However, not every case of belief is knowledge, you are able to believe false things

Knowledge’ can’t just be belief, as knowledge seems to have a property that belief doesn’t

By Leibniz’s law, we can say that belief and knowledge are distinct

Question 9

factive

Answer 9

Things that are known to be true

A factive attitude Q is one such that from A Qs that P, we can infer P

Question 10

Knowledge as True Belief

Answer 10

To know P is to have a true belief that P

Believing truly is factive

However, not every case of believing truly is a case of knowledge

you can know true beliefs just from lucky guesses, but you can’t know something from just guessing

Question 11

Knowledge as a Justified True Belief

Answer 11

Justification would seem to be a necessary condition for knowledge. But it is not a necessary condition for having a true belief

To know P is to have a justified
true belief that P

A knows that P just in case A has a justified true belief that P

We want to ask: Are there any possible cases in which (i) A has a justified true belief that P, but (ii) A
does not know P

Question 12

Justification

Answer 12

justification is person relative

Suppose I see Hanna engaging in various suspicious activities, but you know Hanna as a
pillar of the community.

Then I may be justified in believing that Hanna is a spy, while you would not be justified in believing
that Hanna is a spy.

The reason that justification is person relative is that justification depends on your evidence

Question 13

connection between justification and belief

Answer 13

justified beliefs should be more
likely to be true than non-justified beliefs
But it’s tricky to spell out in exactly what sense this is true

However we can have cases of knowledge that are not justified - eg. coin example of flipping a coin and it being right

you can also have justified beliefs that aren’t true

Question 14

you can also have justified beliefs that aren’t true

Answer 14

incredibly reliable watch. It
has never let you down.

Unfortunately today, as a result of a very unlikely glitch, it has stopped working

Looking at your watch it says 11:30, and on this basis you come to believe it’s 11:30. It is, however, 10:30

In this case, it’s natural to say that you’re justified in your belief, despite the fact that it is false

The reason that you can have false justified beliefs is that sometimes very good evidence can be misleading

Question 15

Justification is something that comes in degrees

Answer 15

Suppose that your evidence entails P

For example your evidence might be Q, R, and the proposition for which it is evidence might be (Q and R)

In this case you have maximal justification for believing the proposition

But sometimes even though your evidence doesn’t entail P, it still makes P very likely

Suppose your evidence is that a bag B contains 100, 000 marbles only one of which is red.

Then your evidence makes it very likely that if you draw a marble it will be non-red

Given that justification comes in degrees, a natural question for the proponent of the JTB account is
what level of justification is required for knowledge

Question 16

answer to what level of justification is required for knowledge (1)

Answer 16

The simplest answer would be maximal justification
But this might seem too demanding

Suppose I parked my car outside my office just before coming to class

It seems plausible that I know that my car is parked outside my office

But although my evidence makes it very likely that my car is outside, it isn’t clear that it entails that my
car is outside, it could have been stolen

Still in this case the natural thing to say is I know that my car is parked outside

Question 17

answer to what level of justification is required for knowledge (2)

Answer 17

So let’s take the JTB account to say, somewhat vaguely, that one requires some sufficiently high level of justification, where this may fall short of maximal justification

When we say that a body of evidence supports P, It’s important that what we mean here is that the total body of evidence that you have supports P

It can happen that some proposition E1 is part of your evidence and that E1 supports P, but your total body of evidence does not support P

An example: If you walk into a room and the wall looks red, then the wall’s looking red is part of your evidence.

This proposition supports believing that the wall is red

However, if you learn that there is trick lighting, then you shouldn’t believe that the wall is red

In this case, you have some evidence, namely, that the wall looks red, that supports a belief P, but your total body of evidence: that the wall looks red, and there is trick lighting, does not support that belief

Here we say that the proposition that there is trick lighting defeats the evidence that the wall looks
red

Question 18

defeasability approach

Answer 18

D defeats E as evidence for P just in case E is evidence for P, but D and E is not evidence for P

Note that evidential defeat can itself be defeated

An example: You go to a party of 100 people and you learn that 98% of the people are accountants

This supports believing that Max, who is at the party, is an accountant

You then learn (i) there are four people wearing vests, (ii) the two non-accountants are wearing vests, and (iii) Max is wearing a vest

This defeats this first bit of evidence

Finally, you learn that only the accountants have gold pens, and Max has a gold pen

This defeats the previous evidence that undermined your initial reason to believe that Max is an accountant

You now again have good—indeed conclusive—reason to believe that Max is an accountant

Ok, so to be justified in believing P, then, is for one’s total evidence to support P to a sufficiently high degree

Question 19

Problem with JTB

Answer 19

if this analysis is correct then, at a
minimum, the following conditional must hold: A knows P just in case A has a justified true belief
that P.

One direction is certainly fine.

The question we want to focus on is whether they are jointly sufficient for knowledge

The question we want to consider is whether there are possible cases in which one has a justified and true belief that P, but one does not know P

the answer to this is yes

Assume, as before, that your watch has stopped working and that it shows 11:30 as the time

But now imagine that instead of looking at your watch at 10:30, you look at it, by chance, at 11:30, and so come to judge that it is 11:30

In this case, by looking at your stopped watch you come to form the true belief that it is 11:30

Moreover, as in the previous watch case, it would seem that since your belief is based on a normally
highly reliable watch, you true belief is also justified

In this case, then, it looks like your belief that it is 11:30 is true and justified, however it is not knowledge, as looking at the stopwatch was no way of learning what the time was

we have a case where we have a justified true belief, but not knowledge

Question 20

another problem with JTB

Answer 20

other cases in which it would seem that one can have a justified true belief without having knowledge

there are cases in which logically valid
inferences would seem to give rise to justified true beliefs that don’t amount to knowledge

Smith and Jones have applied for a job

Smith has strong evidence for:
(J) Jones will get the job and Jones has ten coins in her pocket

On the basis of this Smith deduces:
(J*) There is someone who will get the job and who has ten coins in their pocket

this is a logically valid inference - as if F, therefore something is F

Now let us suppose that, as a matter of fact, the evidence about the job is misleading. In fact, Smith will get the job

And, though Smith doesn’t know this, it turns out that Smith has ten coins in his pocket

J* is still true and justified - it’s justified because Smith has good evidence for it - and J entails J*

but it’s still not the case that Smith knows this

For the reason that (J*) is true is that Smith is the person who will get the job. But Smith doesn’t know that he’ll get the job. And Smith doesn’t know how many coins he has in his pocket

So it looks like if we make the plausible assumption that logically valid inferences preserve justification
then we can have justified true belief without knowledge

A key feature of the preceding is that our logically valid inference takes us from a false (but justified) belief to a true (and seemingly justified belief)

Note that this is possible since while logically valid inferences can’t take us from truths to falsehoods, they can take us from falsehoods to truths

Question 21

another case problem with JTB

Answer 21

(F) Jones owns a Ford

From this Smith then forms the following belief (amongst other similar beliefs):
(F*) Either Jones owns a Ford, or Brown is from Barcelona

Now suppose that the evidence about Jones’ car is misleading

However, as a matter of fact Brown is from Barcelona

This, though, is not something that Smith has any evidence for at all!

F* is a justified true belief, but it is not a case of knowledge

For the reason that (F*) is true is that Brown is from Barcelona. But this is not something that Smith knows

these are called Gettier cases

What would seem to be going on in the problem cases is that the justification for the claim in
question and what makes the claim true aren’t properly connected

Question 22

gettier cases

Answer 22

named after Edmund Gettier who noted these sorts of counterexamples to the JTB account
of knowledge

recipe:
(1) Start with a case in which someone has justified belief in some false proposition P1

(2) Find some logically weaker proposition P2 which is true

To say that P2 is logically weaker than P1 is to say that P2 is entailed by P1, but the reverse is not true

(3) Assume that the agent comes to believe P2 by deducing it from P1

Question 23

Principle of Deductive Closure

Answer 23

f (i) S is justified in believing P, and (ii) P entails Q, and (iii) S comes to
believe Q as a result of inference from P, then S is justified in believing Q

Question 24

Amendments of the JTB account

Answer 24

JTB+1: To know P just is to have a justified true belief that P and to be such that one’s grounds for
believing P don’t include falsehoods

counter argument:
(J1) Jones works in my office and has always driven a Ford in the past and just drove by in a Ford

From this you infer: (J2) There is someone who works in my office who
has always driven a Ford in the past and who just drove by in a Ford

(J3) Someone in my office owns a Ford

But, let us suppose, that Jones does not in fact own a Ford. But someone else at your work, who you do not know, does own a Ford

In this case you have a true belief, that’s justified and that isn’t based on false grounds

However, it’s natural to say in this sort of case that you do not know that someone at your work owns a
Ford

JTB+1 is also too demanding

It would seem that there may be cases in which you know and, amongst your grounds for believing
something, there is some false proposition

eg. you ask twenty witnesses whether
they saw a particular crime. 19 did and truly report this. The other did not but says they did

it would seem that you can know that
the crime took place. But one of propositions that this belief is based on is false

Question 25

factual defeater

Answer 25

Call a factual defeater of E for P, a true proposition that defeats E as evidence for P

Question 26

amendment for JTB, JTB+2

Answer 26

To know P just is to (i) have a justified true belief that P, and (ii) for there to be no proposition that factually defeats one’s evidence for P

In this case Smith’s evidence supports believing (F*) Jones owns a Ford or Brown is from Barcelona, because his evidence supports believing that Jones owns a Ford

the factual defeater: the proposition that Jones does not own a Ford

it seems like in all of the Gettier cases we’ve considered there is a factual defeater

problems with JTB+2: There are cases of knowledge which don’t satisfy the conditions imposed by JTB+2.

Consider the following: You watch Sam steal a book from the library

Unbeknownst to you Sam’s mother has testified that Sam would never steal a book, and that she has an
evil kleptomaniacal twin

Call the proposition that Sam’s mother so testified: Testimony

Now as a matter of fact Sam did steal the book, and Sam’s mother is delusional

It would seem, then, that you know that Sam stole the book

But it would also seem that there is a proposition that factually defeats your evidence for the belief that Sam stole the book, viz., Testimony

Question 27

amendment for JTB, JTB+3

Answer 27

To know that P is just to have a belief that P that is appropriately causally connected to P

There’s a lot to say here about what `appropriate causal connection’ might mean here

But we can get a sense of what we’re after here by considering our Gettier cases, and how such a causal connection might fail to obtain in such cases

Consider again the case of Jones and the Ford

Here Smith believes (F*): Either Jones owns a Ford or Brown is from Barcelona

In this case, what makes (F*) true is just that Brown is from Barcelona.

But this fact isn’t why Smith believes (F*)

In this sense there isn’t the appropriate causal connection between the fact (F*) and Smith’s belief in this fact

problem: Fake barns

You’re driving through a part of the country you haven’t been. Unbeknownst to you, it’s a part of the
country filled with fake barn facades

Now you’re driving by and you see what looks to be a barn and you judge that it’s a barn

As a matter of fact, by a fluke, you’re right

In this case it wouldn’t seem that you know

Still, it seems like there is the appropriate sort of causal connection between the fact that there’s a
barn there and your belief to this effect

So it looks like there being such a causal connection is not sufficient for knowledge