Edmund Gettier's 1963 counterexamples showed that justified true belief, the classical tripartite analysis inherited from Plato's Theaetetus, is not sufficient for knowledge: there are cases of justified true belief that still fall short of knowing. Epistemologists have proposed many candidate fourth conditions since, but the Stanford Encyclopedia of Philosophy's own survey concludes that despite considerable attention, particularly in the late twentieth century, no analysis has been widely accepted.
What would resolve this A precise, counterexample-resistant fourth condition, or a replacement analysis of knowledge altogether, that a broad consensus of epistemologists converges on rather than one that continues to generate further counterexamples.
OpenEpistemologyThe Analysis of Knowledge (Stanford Encyclopedia of Philosophy)