the tripartite view Flashcards
tripartite definition of propsitional knowledge
S knows
that p if and only if:
1 S is justified in believing that p,
2 p is true, and
3 S believes that p (individually necessary and jointly sufficient
conditions)
justification is not necessary
sometimes we use the word ‘know’ just to mean
‘believe truly’. If you can reliably inform me in answer to my query, perhaps that’s enough
for practical purposes to talk of knowledge. true belief can be formed and held in
both good ways and bad, and therefore may not be sufficient for knowledge, but there may be some other
condition that turns true belief into knowledge
Gettier case 1
Smith and Jones are applying for the same job. Smith has excellent reason to believe that Jones will get the job, e.g. Smith has been told this by the employer. Smith also has excellent reason to believe that Jones has ten coins in his pocket, e.g. Smith has just counted them. Therefore, both of these beliefs are justified. Smith then puts the two beliefs together and deduces that the man who will get the job has ten coins in his pocket. This belief is justified, because it is inferred deductively from justified beliefs. However, it turns out that Jones doesn’t get the job, Smith does. It also so happens that, unknown to him, Smith also has ten coins in his pocket. So Smith’s belief that the man who will get the job has ten coins in his pocket happens to be true. Smith’s belief is both true and justified, but we shouldn’t say that Smith knows that the man who will get the job has ten coins in his pocket. Smith inferred his belief from a false belief, namely that Jones would get the job. So the reason Smith has for his belief is
false. What makes his belief true (Smith, who has ten coins in his
pocket, gets the job) has come apart from what justifies his belief (the evidence that Jones, who has ten coins in his pocket, will get the job). There is no connection between what justifies his belief and his belief’s being true. We might say that it is only by luck that his belief is true.
Gettier case 2
Smith believes that Jones owns
a Ford. Smith remembers that for as long as he has known him,
Jones has always had a Ford, and Jones has just offered Smith a lift
while driving a Ford. So Smith’s belief is justified. Smith then thinks
about another acquaintance of his, Brown, and wonders where he
is. He has no idea, and chooses a place name at random, Barcelona,
say. He then deduces the belief (quite oddly, but don’t worry about that) that either Jones owns a Ford or Brown is in Barcelona. An either/or claim is called a ‘disjunction’. A disjunction is true if either (or both) of the two ‘disjuncts’ are true. So ‘Either Jones owns a Ford or Brown is in Barcelona’ is true if
- Jones owns a Ford
- Brown is in Barcelona
- both (1) and (2) are true
Now, from ‘Jones owns a Ford’, Smith can deduce that ‘Either Jones owns a Ford or Brown is in Barcelona’, because it is impossible for the premise ‘Jones owns a Ford’ to be true and the conclusion ‘Either Jones owns a Ford or Brown is in Barcelona’ to be false. His belief that either Jones owns a Ford or Brown is in Barcelona is also
justified, because he has deduced it from his justified belief that Jones owns a Ford. However, unknown to Smith, Jones has just sold his Ford and is currently driving a rented Ford, so he doesn’t own a Ford. But by complete coincidence, and unknown to Smith, Brown is in Barcelona. So the proposition ‘Either Jones owns a Ford or Brown is in Barcelona’ is true – not because of (1), Jones owns a
Ford, but because of (2), Brown is in Barcelona. So Smith’s belief is both true and justified, but we shouldn’t say that Smith knows that either Jones owns a Ford or Brown is in
Barcelona. Once again, Smith inferred his belief from a false belief,
namely that Jones owns a Ford. So the reason Smith has for his belief is false. What makes his belief true (that Brown is in Barcelona) has come apart from what justifies his belief (that Jones owns a Ford). There is, again, no connection between what justifies his belief and his belief’s being true.
infallibilism response
P1. No one can know what is false.
C1. Therefore, if I know that p, then I can’t be mistaken about p.
C2. Therefore, for justification to secure knowledge, justification must
guarantee truth.
C3. Therefore, if I am justified in believing that p, I can’t possibly be mistaken.
C4. Therefore, if it is possible that I am mistaken, then I can’t be justified in
believing that p.
C5. Therefore, infallibilism is true.
no false lemmas condition
- p is true,
- you believe that p,
- your belief that p is justified, and
- you did not infer that p from a false belief
reliabilism response
- p is true,
- you believe that p, and
- your belief is produced by a reliable cognitive process.
truth is not necessary
relativism - we reject talking about ‘truth’ without qualification, and talk
instead about what is ‘true for’ someone or some society. objective truth is too difficult/impossible to prove so we should settle for justified belief that is true ‘for us’ as knowledge
justification is not necessary
We can object that sometimes we use the word ‘know’ just to mean ‘believe truly’, without worrying about justification. There may be some other condition that turns true belief into knowledge eg. reliabilism
belief is not necessary
sometimes it is possible to know
something without believing it eg. answering a question correctly without being confident it’s right. Plato presents argument that knowledge is never a form of belief - knowledge is infallible, because you cannot know what is false, whereas beliefs can be mistaken.
virtue epistemology response
- p is true,
- you believe that p, and
- your belief is a result of you exercising your ‘epistemic’ or ‘intellectual’
virtues.
no false lemmas example
Dr Jones has very good evidence that her patient, Smith, is suffering from virus X, e.g. the symptoms and the lab tests are all consistent with Smith having this virus and no other known virus produces these results. Jones therefore believes that Smith has virus X, and this belief is justified. However, Smith’s symptoms and
lab results are caused by Smith having the unknown virus Y. But, by chance, Smith has just caught virus X, so recently that it has not caused any symptoms nor does it show up in lab tests. So Dr Jones’ belief that Smith has virus X is true. So her belief is both true and justified. But she does not know that Smith has virus X because the evidence from which she infers her belief has nothing to do with the fact that Smith has virus X as it is all caused by virus Y.
Barn county example
Henry is driving through the countryside. He doesn’t know it,
but in this part of the country – call it ‘Barn County’ – there are lots of fake
barns, mere barn facades. But they have been built so that they look just like real barns when seen from the road. As he drives along, Henry often thinks ‘There’s a barn’, or ‘Hey, there’s another barn.’ These beliefs don’t count as knowledge because they are false. But just once, Henry thinks ‘There’s a barn’ when he is looking at the one and only real barn in the area. This belief is true. And it is produced by a very reliable process, namely vision. But it is not knowledge, because – as in other Gettier cases – it is only a matter of luck that Henry’s belief is true in this one instance. But reliabilism has to say Henry does know there’s a barn. His belief is true and produced by a reliable process. The problem is that in Barn County, this reliable process has produced a true belief in circumstances in which the belief still seems only accidentally true.
Zagzebski’s components of virtue
- A virtue motivates us to pursue what is good; in the case of intellectual virtues, we are motivated to discover the truth – so we care about believing what is true, not false.
- A virtue involves a component that enables us to be successful – it gives us the ability to be reliable in forming true beliefs.
Zagzebski’s definition of knowledge
- you believe that p,
- your belief that p arises from an act (or acts) of intellectual virtue.
