Question

The conjunction fallacy is the phenomenon where many people believe that the probability of the event (A AND B) is strictly greater than the probability of the event A. It is usually thought of as an error in reasoning. However, I recall reading a paper in a philosophy journal where the author claimed that, at least in some cases, it is rational to believe that the probability of the event (A AND B) is strictly greater than the probability of the event A. Could that actually be the case? Note, this is separate from the issue of whether it is correct to believe it. Some things are rational to believe, but incorrect. (For example, the case of not drinking a bottle labeled "POISON", when in fact the bottle is perfectly fine, some prankster just labeled it "POISON"). My personal belief is that it is not only incorrect but also irrational to believe the conjunction fallacy, and that the author of that paper is simply trying to use bogus arguments to desperately avoid the conclusion that most people are irrational in believing the conjunction fallacy. But, have any reputable philosophers argued for the rationality of (sometimes) stumbling onto the conjunction fallacy?

Answer 1

While typically considered a reasoning error, there are philosophical arguments suggesting that it can be rational to believe in the conjunction fallacy under certain conditions, usually involving cognitive biases or alternative statistical reasoning.

Step-by-step explanation:

The conjunction fallacy is a common error in reasoning where individuals assume that the probability of two events occurring together (A AND B) is higher than the probability of just one event (A) happening. Though usually considered irrational, certain philosophical arguments suggest it can be rational to believe in the conjunction fallacy under specific circumstances. This perspective relies on understanding cognitive biases and alternative statistical interpretations. For example, cognitive bias such as confirmation bias can lead individuals to overestimate the likelihood of conjunctive events when they align with pre-existing beliefs. Additionally, in specific contexts, Bayesian reasoning may suggest that more detailed scenarios (A AND B) might be perceived as more probable given certain background knowledge, thereby conflicting with traditional interpretations of probability but not inherently irrational.

Furthermore, the conjunction fallacy can sometimes be confused with the fallacy of a false cause, where two events occurring together are incorrectly perceived to have a causal relationship ("correlation does not equal causation"). The fallacy of relevance, fallacy of weak induction, fallacy of unwarranted assumption, and fallacy of diversion are other categories of informal fallacies that can lead to similar errors in reasoning. Known cognitive biases in decision-making, such as the bandwagon fallacy or gambler's fallacy, also demonstrate the complex nature of how people evaluate probabilities and make judgments.