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From: jiml@alberta.UUCP (Jim Laycock)
Newsgroups: sci.philosophy.tech
Subject: Re: Justified true belief
Message-ID: <142@cavell.UUCP>
Date: Wed, 12-Aug-87 19:50:57 EDT
Article-I.D.: cavell.142
Posted: Wed Aug 12 19:50:57 1987
Date-Received: Sat, 15-Aug-87 08:25:54 EDT
References: <90@thirdi.UUCP>
Reply-To: jiml@cavell.UUCP (Jim Laycock)
Distribution: world
Organization: U. of Alberta, Edmonton, AB
Lines: 50
Keywords: knowledge belief truth

In article <90@thirdi.UUCP> sarge@thirdi.UUCP (Sarge Gerbode) writes:
|Awhile back, when we were discussing knowledge and belief, a couple of people,
|as I recall, suggested that knowledge was justified true belief.  Since then,
|I have spoken to a philosopher friend, who pointed out that this criterion
|doesn't hold water, so I thought I'd share his thought with you.  The first
|example is paraphrased from an article by Edmund C. Gettier called "Is
|justified true belief knowledge?":
| [discussion of Gettier counter-example and pyromaniac causal example]
|Each of these examples uses a chain of inferences (logical or causal) in which
|a term earlier than the final one in the chain is one for which a person has
|justified belief but which is not in fact true, and an ultimate term that
|happens to be true and deducible from, or could be caused by, the term that is
|false.
|In order to avoid this problem, it seems that one would have to add another
|proviso to the "justified true belief" criterion, namely that one would
|require justified true belief also in each of the non-ultimate terms in a
|causal or explanatory chain.  A possible difficulty with this formulation is
|that the notion of where an explanatory chain or a causal chain *starts* is
|somewhat up in the air, to say the least.  So you would have a lot of work
|showing that you had justified true belief for anything all the way back to
|the beginning of the chain.  So you would have trouble, using this criterion,
|saying that you know anything.
|Sarge Gerbode

  This is just what I was saying some time ago.  I'll accept the definition
of knowledge as "justified true belief", but then I'll insist (for the very
reasons you pointed out above) that, given this definition, knowledge is
not attainable.  But we shouldn't despair at this fact, nor should we
lapse into relativism.  There's alot we can do with well-substatiated
and well-corroborated evidence.
  We must also be careful, in our discussion, to steer away from the
colloquial definition of knowledge.  Our `knowledge' is a technical term, and
is to be divorced from "acquainted with" or "have a pretty good idea about"
concepts.
  One thing that has bothered me about these discussions, however, is that
people have been taking for granted the following two propositions:
 
  1.  Bel(p) & Bel(q) -> Bel(p & q)
  2.  Bel(p) or Bel(q) -> Bel(p or q)

These seem to give rise to many of our so-called epistemic paradoxes, so
that in itself might be reason to cast them in doubt.  One would have a
much weaker epistemic logic if one were to abandon these principles, but
I don't thing they're psychologically appealing.  Alot goes on in the `->'
st
-- 
  Jim Laycock		Philosophy grad, University of Alberta
  alberta!Jim_Laycock@UQV-MTS
    OR
  decvax!bellcore!ulysses!mhuxr!mhuxn!ihnp4!alberta!cavell!jiml