There are things like "lying for a good cause", which is a textbook example of what will go horribly wrong because you almost certainly underestimate the second-order effects. Like the "do not wear face masks, they are useless" expert advice for COVID-19, which was a "clever" dark-arts move aimed to prevent people from buying up necessary medical supplies. A few months later, hundreds of thousands have died (also) thanks to this advice. (It would probably be useful to compile a list of lying for a good cause gone wrong, just to drive home this point.) Thinking about historical record of people promoting the use of dark arts within rationalist community, consider Intentional Insights. Turned out, the organization was also using the dark arts against the rationalist community itself. (There is a more general lesson here: whenever a fan of dark arts tries to make you see the wisdom of their ways, you should assume that at this very moment they are probably already using the same techniques on you. Why wouldn't they, given their expressed belief that this is the right thing to do?) The general problem with lying is that people are bad at keeping multiple independent models of the world in their brains. The easiest, instinctive way to convince others about something is to start believing it yourself. Today you decide that X is a strategic lie necessary for achieving goal Y, and tomorrow you realize that actually X is more correct than you originally assumed (this is how self-deception feels from inside). This is in conflict with our goal to understand the world better. Also, how would you strategically lie as a group? Post it openly online: "Hey, we are going to spread the lie X for instrumental reasons, don't tell anyone!" :) Then there are things like "using techniques-orthogonal-to-truth to promote true things". Here I am quite guilty myself, because I have long ago advocated turning the Sequences into a book, reasoning, among other things, that for many people, a