Mass_Driver: [...] I'm not sure if that would be a smart move, since it would mean an extremely high concentration of unsupported controversial claims in a single post. Many of my opinions on these matters would require non-obvious lengthy justifications, and just dumping them into a list would likely leave most readers scratching their heads. If you're really curious, you can read the comment threads I've participated in for a sample, in particular those in which I argue against beliefs that aren't specific to my interlocutors. Also, it should be noted that the exact composition of the list would depend on the granularity of individual entries. If each entry covered a relatively wide class of beliefs, creationism might find itself among the top fifty (though probably nowhere near the top ten).

I've separated some forms of alternative medicine out when one might arguably put them closer together. Also, I'm including Young Earth Creationism, but not creationism as a whole. Where that goes might be a bit more complicated. There's some overlap between some of these (such as young earth creationism and religion). The list also does not include any beliefs that have a fundamentally moral component. I've tried to not include beliefs which are stupid but hard to deal with empirically (say that there's something morally inferior about specific racial groups). Finally, when compiling this list I've tried to avoid thinking too much about the overall balance that the delusion provides. So for example, religion is listed where it is based on the harm it does, without taking into account the societal benefits that it also produces. 1-4: Religion, Ayurveda, Homeopathy, Traditional Chinese medicine (as standardized post 1950s) 5-10 The belief that intelligence differences have no strong genetic component. The belief that intelligence differences have no strong environmental component. The belief that there are no serious existential threats to humans. The belief that external cosmetic features or national allegiances are strong indicators of mental superiority or inferiority. That human females have fundamentally less mental capacity and that this difference is enough to be a useful data point when evaluating humans. The belief that the Chinese government can be trusted to benefit its people or decide what information they should or should not have access to. (The primary reason this gets on the list is the sheer size of China. There are other governments which are much, much worse and have similar delusions by the people. But the damage level done is frequently much smaller.) 11-20 Vaccines cause autism. Young Earth Creationism. Invisible Hand of the Market solves everything. Government solves everything. Providence. That there are not fundamental limits on certain n