The meaning of "knowledge"

[ptc24]

Hypothetical:

In Town X, a burglary is reported to the police. They investigate, and their investigation leads to Bob, who has previous convictions for that sort of thing. They find the stolen goods at Bob's house, Bob is questioned, he confesses, it goes to trial, Bob pleads guilty, the jury is convinced by the evidence, and Bob is sentenced accordingly.

In fact, Bob had not committed the burglary. In fact, he had a provable alibi - he was out committing another burglary (of equivalent severity) elsewhere in town at the time. The original burglary was done by a friend of his, and he was just storing the goods at his house. Given that demonstrating his alibi wouldn't have saved him any prison time, and would have involved fingering his accomplices (which would have damaged his standing in the criminal underworld), he felt that the simplest thing to do was to take the rap for the original burglary.

This is all to illustrate a philosophical point about the word "know" (and "knowledge" etc). A poll:

(ETA Note that the previous convictions don't count when I'm asking whether the legal system knew Bob had committed burglary... I meant to ask "...committed burglary on that day" or something similar. This ETA is before anyone but me has answered this, so all the results reflect this ETA)

Poll #10225

Open to: Registered Users, detailed results viewable to: All, participants: 9

View Respondents

Did the legal system know that Bob had committed burglary?

View Answers

Yes
1 (12.5%)

No
7 (87.5%)

Was the outcome just?

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Yes - Bob committed a burglary and served a sentence for burglary, your point?
4 (57.1%)

No - Bob was punished for a crime he did not commit.
2 (28.6%)

I don't believe in punishing people for burglary anyway, so No
1 (14.3%)

Furthermore

View Answers

This is a completely ridiculous hypothetical and the legal system wouldn't have acted that way
0 (0.0%)

This is reasonably realistic, at least in terms of how the legal system acted
2 (25.0%)

Ummmm...
6 (75.0%)

Comments

[simont]

It seems to me that when we combine your hypothetical here, my one (and the one in the comments) in the old LJ post I linked to, and Gettier's ones in the Wikipedia page you link to, the common thread is that all of them have a true belief of the form "One of the following set of possibilities is true", with a justification "Specifically, I have reason to believe it's this one". In fact it then turns out that the thing asserted in the justification is false in spite of looking plausible, but fortunately one of the other possibilities in the set is true, and thus the originally stated belief manages to be true despite the justification being wonky.

Are there any examples of this phenomenon which don't have that form?

[ptc24]

In a comment above I had something from an RPG which doesn't obviously fit that form, although maybe it could be argued to have it. It's also complicated by questions of personal identity which are a whole different philosophical can of worms.

[simont]

Hmmm. So in that situation, the Assassin has the belief "The Scum is an unsanctioned psyker", justified by the observations that (a) the Scum is not a sanctioned psyker, and (b) the Scum just used a psi ability. But in a world where mind-swapping is actually possible (and moreover can happen unexpectedly and without obvious external signs), we have to expand that reasoning a bit and expose the implied assumption, so that it goes more like: (a) the Scum's mind is not a sanctioned psyker, (b) the Scum's body just used a psi ability, (c) we presume that the Scum's body is currently occupied by the Scum's mind. Of course the error in the reasoning is (c), and for all that it's an understandable assumption if mindswaps are possible but very rare, it's still inaccurate.

(Also, the above reasoning only yields the belief that the Scum's mind is an unsanctioned psyker; that must be combined with point (c) a second time to reach the conclusion that it's legitimate to gun down the Scum's body right now. That latter conclusion is certainly not knowledge, since it's not even true. Only the intermediate conclusion about the Scum's mind constitutes the sort of quasi-knowledge we're discussing here.)

I think I'd agree that it's not clear that this fits into my suggested unifying pattern.