Scott Alexander uses three fictional stories to illustrate principles of non-empirical scientific reasoning, ultimately applying them to support the many-worlds interpretation of quantum mechanics. Longer summary

This post presents three fictional stories to illustrate important points about non-empirical arguments in science. The first story shows that even when two theories make identical predictions, it's important to choose the simpler one. The second story demonstrates that determining which theory is simpler isn't always straightforward and requires philosophical understanding. The third story ties these concepts to quantum mechanics, arguing that the many-worlds interpretation is preferable to single-world interpretations based on these principles. Shorter summary

Scott Alexander argues that non-empirical reasoning, based on principles like simplicity and elegance, is a necessary and legitimate part of scientific practice, even for evaluating seemingly untestable theories. Longer summary

Scott Alexander discusses the role of non-empirical arguments in science, challenging the view that untestable theories are inherently unscientific. He argues that even in cases where direct empirical testing is impossible, scientists use principles like simplicity and elegance (often formalized as Occam's Razor) to evaluate competing theories. Scott uses examples ranging from paleontology vs. creationism to multiverse theories in physics to demonstrate that this type of reasoning is both necessary and legitimate in scientific practice. He concludes that while there may be debates about the best way to formalize or apply these principles, it's crucial to recognize that some form of non-empirical reasoning is an inescapable part of the scientific process. Shorter summary

Scott Alexander's experiment tested how different essays affect people's concerns about AI risk, finding a modest but persistent increase in concern after reading. Longer summary

Scott Alexander conducted an experiment to test the effectiveness of different essays in persuading people about AI risk. Participants were assigned one of five essays to read, including a control essay unrelated to AI. The main outcome was participants' level of concern about AI risk on a 1-10 scale. Results showed that reading the AI-related essays increased concern by an average of 0.5 points, with no significant differences between the four AI essays. The effect persisted at about two-thirds strength after one month. The experiment also looked at secondary outcomes related to specific AI risk questions and analyzed differences based on prior familiarity with the topic. Overall, the study suggests a modest but useful effect from trying to persuade people through essays on this topic. Shorter summary

Scott explores the implications of Sean Carroll's argument against the simulation hypothesis, suggesting that our inability to explain consciousness might indicate we're in a 'ground-level' simulation. Longer summary

Scott Alexander discusses Sean Carroll's argument against the simulation hypothesis, exploring the implications if Carroll's reasoning is correct. He posits that a 'ground-level' universe, incapable of simulating other universes, would have to be strange, potentially banning Turing machines while still allowing for conscious observers. Scott then considers a version of anthropics conditioned on consciousness, suggesting that in a ground-level simulation, consciousness would remain inexplicable to its inhabitants despite their ability to understand all other aspects of their universe. He concludes that if Carroll's deconstruction is correct, our difficulty in explaining consciousness might indicate we're in a ground-level simulation. Shorter summary