Scott Alexander partially retracts his previous post on animal value and neural number after a commenter's larger survey yielded different results. Longer summary

Scott Alexander partially retracts his previous post about animal value and neural number. A commenter, Tibbar, replicated Scott's survey using Mechanical Turk and obtained different results with a larger sample size. Scott acknowledges that while Mechanical Turk users might not be the ideal sample and some responses seem rushed, it's difficult to claim his original results represent a universal intuitive understanding. He explains that his original sample was more informed about animal rights issues. Scott adds this to his Mistakes page and considers including a similar survey in the future, hoping readers will have forgotten about this retraction. Shorter summary

Scott Alexander finds a correlation between animals' cortical neuron count and people's intuitive perception of their moral value, based on a small survey. Longer summary

This post explores the correlation between the number of cortical neurons in animals and humans' intuitive perceptions of their moral value. Scott Alexander conducted a survey asking people to estimate how many of each animal would equal one human in moral value. He then compared these results to the relative number of cortical neurons each animal has compared to humans. The results showed a surprisingly close match, with some exceptions like lobsters. Scott suggests this adds credibility to intuitive ways of thinking about animal moral value, though he acknowledges the need for further research with a larger, more representative sample. Shorter summary

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