Scott Alexander critiques Dylan Matthews' argument against prioritizing existential risk reduction, arguing that Matthews misuses probabilities and that his logic could also undermine other effective altruist causes. Longer summary

Scott Alexander critiques Dylan Matthews' argument against prioritizing existential risk reduction in effective altruism. Matthews claims that the probabilities used in x-risk arguments are made up and could be as low as 10^-66. Scott argues that such extremely low probabilities are unrealistic and that Matthews is misusing numbers. He explains that even with rough estimates, the case for prioritizing x-risk remains strong. Scott also points out that similar arguments could be used against other causes Matthews supports, like animal welfare. He concludes by advocating for a big tent approach in effective altruism that respects different cause prioritizations, including x-risk, while acknowledging that x-risk might not be the best public face for the movement. Shorter summary