A theory that understood this concept using causal chains was later challenged with “fake barn” cases introduced by the reliabilist thinker Alvin Goldman. Four conditions need to be met in the truth-tracking theory (10[1])of this concept proposed by Robert Nozick. A three-page 1963 paper challenges a definition of this concept with a case where Smith thinks Jones will get a job and also has ten coins in his pocket. That case, developed by Edmund Gettier, challenges Plato’s definition of this concept in the (-5[1])Theaetetus as “justified true (10[2])belief.” (10[3]-5[1])This concept is studied in epistemology. (10[1])For 10 points, skeptics doubt the existence (-5[1])of what concept that Francis Bacon claimed “is power”? (10[1])■END■ (10[1])