We'll be taking people's questions about life, philosophy, and rationality, and giving them our best off-the-cuff answers here on the CFAR blog.
Q: "How do we confront the fact that having false beliefs is sometimes more efficient and productive?"
A: I'm willing to accept that, in principle, false beliefs can help you achieve your goals. But in practice, I think self-deception is rarely your best option.
Basically, the problem with self-deception is that (1) it doesn't work that well -- if you decide to self-deceive, then usually on some level you're aware of the deception, and (2) if it does work, you're opening yourself up to a lot of other biases in order to preserve the lie. For example, if you convince yourself that you're talented at public speaking when you're actually not, that might seem useful in the short term because it gives you confidence. But what happens when someone critiques your speech? In order to keep believing your lie, you now need to explain to yourself why they didn't like your speech, so you might decide they're just jealous (for example). Now you're introducing more false beliefs into your world model, and potentially harmful ones at that.
That said, there's a difference between believing something and obsessing about it. There's no epistemic law requiring you to dwell on unpleasant or unhelpful truths.
For example, when I've decided to take a calculated risk, knowing that I might well fail but that it's still worth it to try, I often find myself worrying about failure even after having made the decision to try. And I might be tempted to lie to myself and say, "Don't worry! This is going to work!" so that I can be relaxed and motivated enough to push forward.
But instead, in those situations I like to use a framework CFAR sometimes calls "Worker-me versus CEO-me." I remind myself that CEO-me has thought carefully about this decision, and for now I'm in worker mode, with the goal of executing CEO-me's decision. Now is not the time to second-guess the CEO or worry about failure.
This is just one example of how to keep stressful truths from paralyzing you without needing to actually deny those truths. It won't work in all situations, or for all people, but it's a proof of concept -- when it feels like you need to deceive yourself in order to achieve some goal, there is usually an alternate path to that goal that doesn't require self-deception.