Gettier

The Analysis of Knowledge
First published Tue Feb 6, 2001; substantive revision Mon Jan 16, 2006
The objective of the analysis of knowledge is to state the conditions that are individually necessary and jointly sufficient for propositional knowledge: knowledge that such-and-such is the case. Propositional knowledge must be distinguished from two other kinds of knowledge that fall outside thescope of the analysis: knowing a place or a person, and knowing how to do something. The concept to be analyzed — the analysandum — is commonly expressed using the schema “S knows that p”, where “S” refers to the knowing subject, and “p” to the proposition that is known. A proposed analysis consists of a statement of the following form: S knows that p if and only if ___. The blank is to be replacedby the analysans: a list of conditions that are individually necessary and jointly sufficient. To test whether a proposed analysis is correct, we must ask (a) whether every possible case in which the conditions listed in the analysans are met is a case in which S knows that p, and (b) whether every possible case in which S knows that p is a case in which each of these conditions is met. When weask (a), we wish to find out whether the proposed analysans is sufficient for S's knowing that p; when we ask (b), we wish to determine whether each of the conditions listed in the analysans is necessary.
• 1.Knowledge as Justified True Belief
o 1.1 The Belief Condition
o 1.2 The Justification Condition
• 2. The Gettier Problem
• 3. An Alternative Approach:Reliabilism
• 4. Internalism and Externalism
• 5. Why Internalism?
• 6. Why Externalism?
• 7. Two Analyses of Knowledge
• Supplement: Knowledge and Skepticism
• Bibliography
• Academic Tools
• Other Internet Resources
• Related Entries
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1. Knowledge as Justified True Belief

According to the following analysis, which is usually referred to as the“JTB” account, knowledge is justified true belief.
The JTB Analysis of Knowledge:
S knows that p iff
i. p is true;
ii. S believes that p;
iii. S is justified in believing that p.
Condition (i), the truth condition, has not generated any significant degree of discussion. It is overwhelmingly clear that what is false cannot be known. For example, it is false that G. E. Moore is the author ofSense and Sensibilia. Since it is false, it is not the sort of thing anybody can know.
Although the truth-condition enjoys nearly universal consent, let us nevertheless consider at least one objection to it. According to this objection, Newtonian Physics is part of our overall scientific knowledge. But Newtonian Physics is false. So it's possible to know something false after all.[1]
Inresponse, let us say that Newtonian physics involves a set of laws of nature {L1, L2,…, Ln}. When we say we know Newtonian physics, this could be interpreted as saying we know that, according to Newtonian physics, L1, L2,…, Ln are all true. And that claim is of course true.
Additionally, we can distinguish between two theories, T and T*, where T is Newtonian physics and T* updated theoretical physics atthe cutting edge. T* does not literally include T as a part, but absorbs T by virtue of explaining in which way T is useful for understanding the world, what assumptions T is based on, where T fails, and how T must be corrected to describe the world accurately. So we could say that, since we know T*, we know Newtonian physics in the sense that we know how Newtonian physics helps us understand theworld and where and how Newtonian physics fails.

1.1 The Belief Condition

Unlike the truth condition, condition (ii), the belief condition, has generated at least some discussion. Although initially it might seem obvious that knowing that p requires believing that p, some philosophers have argued that knowledge without belief is indeed possible. Suppose Walter comes home after work to...