What is knowledge? Belief, truth, and justification
Knowing something seems to require more than believing it, and more than being lucky enough to be right.
Three kinds of knowing
Philosophers distinguish knowing how (riding a bike), knowing by acquaintance (knowing a city), and propositional knowledge, knowing that something is true. Epistemology focuses mainly on the last kind. The question is what must be added to a true belief to turn it into knowledge.
The traditional analysis
A long-standing answer says that knowledge is justified true belief. You know that a claim is true if you believe it, it really is true, and you have good reasons for believing it. Each part matters: a false belief is never knowledge, and a true belief held for no reason, such as a lucky guess, does not count either.
Gettier cases
In 1963 Edmund Gettier described cases where all three conditions hold but we would not call the belief knowledge. Imagine you look at a stopped clock that happens to show the right time. You believe it is 3:00, it is 3:00, and trusting a clock is usually reasonable, yet you only got it right by luck. Such cases show justification and truth can line up by accident.
Flashcard
The traditional analysis of knowledge
Check your understanding
Lena glances at a broken clock that happens to show the correct time and forms a true belief about the time. What does this example illustrate?