The Gettier problem is a thought experiment in philosophy that throws into question the long-held supposition that to know something is equivalent to holding a belief about something that is both true and for which there is justification. Consider a case in which a lecturer has two students in her class called Mr. Havenot and Mr. Havegot. Mr. Havenot claims to own a Ferrari, drives one around, and has papers which state that the car is his. But in fact he does not actually own the car. Mr. Havegot, on the other hand, who shows no sign of Ferrari ownership, secretly has one of these rare cars. On the basis of the evidence, the teacher concludes that one of her students owns a Ferrari – and is correct in this belief. However, there is something wrong. Despite the combination of truth, justification, and belief, it seems that there is no real knowledge. The first examples of such problems were published in 1963 by the American philosopher Edmund Gettier (1927–2021).