If evidence required only justified true belief, or some other good cognitive status short of knowledge, then a critical mass of evidence would set off a kind of chain reaction.
Gettier, Edmund 1963: "Is Justified True Belief Knowledge?".
Suppose knowledge is analyzable as justified true belief
. Then the fact that, for all propositions P, someone knows P iff the has justified true belief
in P seems not to stand in need of explanation.
If justification is understood to require the possession of such evidence, then talk of "justified true belief" is redundant; justification guarantees truth.
Since Gettier's "Is Justified True Belief Knowledge?," this requirement has most frequently put simply as the requirement that the true belief in question be justified.
Musgrave opens the book defending the general claim that knowledge consists of justified true beliefs. He concedes that there may well be other kinds of knowledge - knowledge of things (knowledge by acquaintance), knowing how (skill knowledge) - but still, he contends, there is much of interest in "knowledge that" (propositional knowledge), and this kind of knowledge is best analyzed in terms of a justified true belief account.
At the beginning of the book Musgrave frames what follows with arguments supporting a justified true belief account of knowledge.
It addresses the assumption that Korean War veterans did not suffer from post-traumatic stress disorder; the differences between public knowledge and justified true beliefs
about the war; the lack of appreciation of veterans; myths about the Marines winning the war, Eisenhower ending it, and the invasion at Inchon; the confusion after the disclosure of the massacre at No Gun Ri; the role of the press, radio, magazines, television, films, historians, books, songs, and memorials and monuments in misconceptions; and continuing misconceptions about the war.
In sum, we can articulate a basic account of group knowledge that parallels individual knowledge with regard to the components of justified true beliefs
. (50) However, the parallels run deeper still.