Hi! I wonder what "knowledge" is. I heard the JTB argument that says knowledge must be a justified, true belief. Then there is the Gettier problem in which JTB is not sufficient to describe knowledge. But I suppose, to say that "JTB is not enough for knowledge", one must have a definition of knowledge in the first place which is not "justified, true belief". So I was so curious what the definition of knowledge, about which philosophers have been discussing so long, actually is?

You're right that according to the JTB analysis of the concept of knowledge (it's really an analysis rather than an argument), propositional knowledge is identical to justified, true belief. Gettier cases, as you say, are meant to show that knowledge requires more than justified, true belief. But Gettier cases don't proceed by assuming a different analysis (or definition) of knowledge than the JTB analysis: if they did that, they would be guilty of begging the question against the JTB analysis.

Instead, Gettier cases involve scenarios in which intuitively the subject lacks knowledge of a proposition despite having a justified, true belief of the proposition. We're supposed to agree that, intuitively, Smith doesn't know the proposition Jones owns a Ford or Brown is in Barcelona, even if we don't have in mind any specific definition of "knowledge."

Compare: If I propose an analysis of the concept of a lie on which a lie is nothing more than a false utterance, you can refute my analysis by pointing to any case in which someone innocently misspoke and got the facts wrong. You can do so without having in mind a specific definition of "a lie."

What, then, is the correct analysis of knowledge? Good question. See this SEP entry for an excellent discussion of the topic.

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