definitions of knowledge Flashcards
the tripartite definition (JTB)
the standard knowledge dating back to the time of Plato - to know that something is true we not only have to believe it but also need to have justification for our belief.
necessary and sufficient conditions
A necessary condition is a true statement but may not make the entire argument true. A sufficient condition is what makes the argument true.
problems for justified true belief
Gettier’s paper describes two scenarios where an individual has a JTB that is not knowledge. Both scenarios describe a belief that fails to count as knowledge because the justified belief is only true as a result of luck.
Gettier’s Case 1
- Smith and Jones are interviewing for the same job
- Smith hears the interviewer say “I’m going to give Jones the job”
- Smith also sees Jones count 10 coins from his pocket
- Smith thus forms the belief that “the man who will get the job has 10 coins in his pocket”
- But Smith gets the job, not Jones
- Then Smith looks in his pocket and, by coincidence, he also has 10 coins in his pocket
Gettier’s Case 1 explained
Smith’s belief “the man who will get the job has 10 coins in his pocket” is:
- Justified: he hears the interviewer say Jones will get the job and he sees that Jones has 10 coins in his pocket
- True: the man who gets the job (Smith) does indeed have 10 coins in his pocket
But despite being a JTB, we don’t want to say that Smith’s belief counts as knowledge as it’s just luck that led to him being correct. This shows that the tripartite definition of knowledge is not sufficient: you can’t have a justified true belief that isn’t knowledge.
Gettier’s Case 2
- Smith has a justified belief that “Jones owns a Ford”
- So, using the principle of disjunctive introduction above, Smith can form the further justified belief that “Either Jones owns a Ford or Brown is in Barcelona”
- Smith thinks his belief that “Either Jones owns a Ford or Brown is in Barcelona” is true because the first condition is true (i.e. that Jones owns a Ford)
- But it turns out that Jones does not own a Ford
- However, by sheer coincidence, Brown is in Barcelona
Gettier’s Case 2 explained
So, Smith’s belief that “Either Jones owns a Ford or Brown is in Barcelona” is:
True: “Either Jones owns a Ford or Brown is in Barcelona” turns out to be true. But Smith thought it was true because of the first condition whereas it turns out it is true because of the second condition
Justified: The original belief “Jones owns a Ford” is justified, and so disjunction introduction means that the second belief “Either Jones owns a Ford or Brown is in Barcelona” is also justified.
But despite being a JTB, it is wrong to say that Smith’s belief counts as knowledge, because it was just luck that led to him being correct. This again shows that the tripartite definition of knowledge is not sufficient.
JTB + No false lemmas
No false lemmas definition of knowledge aims to strengthen the justification condition of the tripartite definition.
It says that James has knowledge of P if:
- P is true
- James believes that P
- James’s belief is justified
- James did not infer that P from anything false
how does JTB + no false lemmas avoid Gettier’s case
This avoids the problems of Gettier cases because Smith’s belief “the man who will get the job has 10 coins in his pocket” is inferred from the false lemma “Jones will get the job”.
problem for JTB + no false lemmas
fake barn county
fake barn county
- In ‘fake barn county’, the locals create fake barns that look identical to real barns
- Henry is driving through fake barn county, but he doesn’t know the locals do this
- Henry often thinks “there’s a barn” when he looks at the fake barns
- These beliefs are not knowledge, because they are not true – the barns are fake
- However, on one occasion Henry looks at the one real barn and thinks “there’s a barn”
- This time the belief is true, justified by his visual perception of the barn and it’s not inferred from anything false
According to the no false lemmas definition, henry’s belief is knowledge. But this shows that the no false lemmas definition must be false. Henry’s belief is clearly not knowledge – he’s just lucky in this instance.
Reliabilism
The theory that you know that p if p is true, you believe that p, and your belief is caused by a reliable cognitive process.
If you form a belief through an unreliable method – for example by simply guessing – then it would not count as knowledge even if the resultant belief is true.
examples of reliable methods for reliabilism
- good eyesight
- accurate memory
advantages of reliabilism
An advantage of reliabilism is that it allows for young children and animals to have knowledge.
- Typically, we attribute knowledge to young children and animals. E.g., it seems perfectly sensible to say that a seagull knows where to find food or that a baby knows when its mother is speaking.
- unlike other definitions of knowledge, both young children and animals are capable of forming beliefs via reliable processes, e.g., their eyesight, and so according to reliabilism are capable of possessing knowledge.
problem for reliabilism
fake barn county
- Henry’s true belief that “there’s a barn” is caused by a reliable cognitive process – his visual perception. Reliabilism would thus (incorrectly) say that Henry knows “there’s a barn” even though his belief is only true as a result of luck.
