Refuse to believe what isn't useful

I've previously written that truth and utility are not the same.

Corollary: you shouldn't believe things which are bad for you.

Moral claims that white people "should" pay reparations to black people can be refuted on moral grounds, or on the correct grounds that morality doesn't exist. But they can equally well be refuted by saying "No." Refusal is refutation. People who believe in the importance of truth will say that action is not argument or refutation. But they beg the question by assuming that truth is more important than utility. This belief in the "importance" of truth is a moral belief, and therefore wrong. It is more efficient to say "I am not going to believe that because it does not benefit me. I am not going to bother arguing with you, or thinking about it to convince myself. I am not going to do it."

Contrary to popular belief, you can choose what you believe.

Corollary: most people already do this. Most people's beliefs are determined by what is good for them. People whose beliefs are determined by what is good for them will tend to out-compete people who prefer to believe what they think is true. Ordinary people are not obsessed with philosophy.

In Donald Hoffman's talk "Do we see reality as it is?", he describes computer models which indicate that people who perceive reality in a way which increases their fitness, tend to outcompete people who perceive reality accurately.

Ways in which true beliefs can be bad for you

• Knowing how to build a nuclear reactor, which then explodes. "A little knowledge is a dangerous thing."
• Disbelief in god when non-believers are killed. Disbelief in the socially dominant ideology when this is punished by society. Even if no one believes it, revealing non-belief can be fatal.
• If you accurately know your own abilities, you may not take risks which would be good for you. You may be less confident which could be bad for you.
• Self-deception and the having of emotions can be good for you. Instead of faking an emotion, you have it for real, and use this to get what you want.
• Anti-natalism. If you don't believe life has a purpose, you are less likely to procreate.

Truth versus utility

Instrumental and epistemic rationality tend to be correlated, because there is an objective world. Concepts are mental tools: don't ask if a belief is true, ask if it is useful.

Scientific theories are concepts, tools. The epistemic way to evaluate a scientific theory is to see how accurate its predictions are. This is epistemic rationality.

But the instrumental way to evaluate a theory is to see how adaptive believing it is. Is believing it good for your genetic fitness?

These are not the same. Science is a commitment to truth, but that is not necessarily good for you. Accurate predictions are not the same as utility.