[MD] JTB

[Steven Peterson]

Hi Ian,


On Wed, Dec 22, 2010 at 1:09 PM, Ian Glendinning
<ian.glendinning at gmail.com> wrote:
> Hmm, I think Matt's thought experiment is more than "getting lucky".
>
> The issue is really to do with time. Hindsight, evidence after believing.
> Truth and justification for truth can be closely aligned afterwards.
> Beforehand is a prediction or speculation of something that may or may
> not be true, with or without good justification.
>
> Believing Dave to be holding the Jack of Spades (with no particular
> reasonable evidence) is hoping or guessing that something might be
> true, not holding that something IS true.


Steve:
No, I'm pretty sure that I understood what Matt meant. Here are some
other examples to illustrate the semantic importance of the
justification/belief distinction when we talk about knowledge:


Situation I:

Suppose Joe believes he has $20 in his wallet. He is justified in
believing it. He remembers putting it there himself. When he goes to
buy some coffee, he finds that his wallet is empty. It turns out that
his daughter had taken the money out of his wallet without telling
him. Joe had a justified but false belief about his $20. He thought
that he knew that he had $20 in his wallet, but it turned out that he
did not know.

The distinction here between justification and truth is useful for
maintaining the cautionary notion that what we are justified in
believing sometimes turns out to be false. We don't usually say
(following James who I think lost this semantic battle) that the
belief about the $20 was MADE false by trying to verifying. That usage
never caught on. It is rather common usage to say that "Joe has $20 in
his wallet" was false ever since Joe's daughter removed the money
rather than at the point when the removal of the money registered in
Joe's experience.



Situation II:

Suppose Joe believes he has $20 in his wallet. He is justified in
believing it. He remembers putting it there himself.  Without his
knowledge, Joe's daughter takes the money from his wallet, but Joe's
awesome wife later noticed that Joe had no money in his wallet and
puts $20 in for him in case he needs it. When Joe goes to buy some
coffee, he opens his wallet and thinks to himself "see? I KNEW I had
$20 in my wallet."

But did he? The $20 in his wallet now is not the one he remembers
putting in his wallet. It is indeed true that there is $20 in his
wallet, but did he KNOW that he had $20? Was he JUSTIFIED in believing
he had $20 in his wallet? It is not enough to say that his belief
turned out to have been true. He also must have a good belief for
"definite assignable reasons." In this case, his reason was wrong
despite having a true belief. With the JTB notion, that isn't
knowledge. He needs not only a good belief but good justification for
that belief.







Ian:
> As I tried to say before in this thread, I actually agree it is
> splitting pedantic hairs to either make, or insist in not making, the
> truth-justification distinction, because when all is said and done,
> both truth and justification rely on "good" and "evidence". Both.
>

Steve:
I think there are two separate issues when we use the word "knowledge."
1. Is the belief good?
2. Is the justification for holding the belief good?

Without having both a good belief and a good justification for holding
that belief we don't have knowledge.



Ian:
> In that sense I agree with Dave, good evidence is the most immediately
> experienced (choose your preferred terminology). ie What is good ?


??? What do you mean by "most immediately experienced? What is more
immediately experienced than what?

Best,
Steve