Page 85-86: Is Justified True Belief Knowledge? (JTB):
What is knowledge? A traditional answer is that knowledge is a form of justified true belief. To know that s is F is to be fully justified in one's (true belief that s is F. Normally, these conditions are interpreted so as to be independent of one another. Beliefs can be false, and the truth may not be believed. Furthermore, one can be fully justified in believing s is F without s's being F (in which case, of course, one does not know) and have a full justification for something one does not believe.
Although still used as a touchstone for epistemological discussion, this orthodox account is no longer deemed satisfactory. It must be either abandoned or severely qualified to withstand a variety of crippling objections. Aside from objections, however, the account remains seriously incomplete insofar as the concept of justification is left unanalyzed. It is of no help to be told that knowledge depends on having an adequate justification if. as is often the case, one is not told what constitutes an adequate justification.
I propose to replace this traditional account with an information-theoretic analysis. This chapter is a first step in that enterprise. What follows is a characterization of knowledge in terms of information and belief. Later (Part III) belief itself will be resolved into the informational components, but for the time being, I will use this concept as an auxiliary deviceto abbreviate matters and postpone issues that can only be attended to later.
When there is a positive amount of information associated with s's being F,
K knows that s is F = K's belief that s is F is caused (or causally sustained) by the information that s is F.
It should be emphasized at the outset that this is intended to be a characterization of what may be called perceptual knowledge, knowledge about an item s that is picked out or determined by factors other than what K happens to know (or believe) about it. That is, following our discussion of de re informational contents in the last chapter, we are concerned with knowing of something that it is F where something known to be F is fixed by perceptual (noncognitive) factors. We shall, in a later chapter, discuss the nature of the perceptual object—what it is we see, hear, and smell. There will be argued that the perceptual object is, so to speak, the focus of the information relations holding between the subject and the sources from which he or she receives information. But until this point can be clarified, I must ask the reader to understand s to be something K perceives, something at an informational source about which K receives information. If K has a belief about this object, the belief that it is F, then this belief qualifies as knowledge if and only if that belief is caused (or causally sustained) by the informationthat it is F.
This analysis may appear circular. Knowledge is identified with information-produced (or sustained) belief, but the information a person receives (Chapter 3) is relative to what he or she already knows about the possibilities at the source. Since there is a covert reference to knowledge on the right-hand side of the equation (cocealed within the idea of information), the equation does not tell us, as it purports to tell us, what knowledge is in its use of the concept information.
DNF:
I give up on this mildly speaking unclear logic:
Terminology: Symbols undefined, obviously set in italics as a lot of other text.
Open-ended: lots of references to stuff to be covered later, or has been covered before.
Fluffy: this book has obviously been a painful rush job and to comply with US academic slavery rules.