Rational beliefs are the most certain beliefs you can have that are justified given the information you have. (They are Bayesian probability theory calculations that you do in your head.) It is always in your best interest to be rational, even if you pretend not to be, because better beliefs will help you make better decisions about how to achieve your interests.

Moral behavior, on the other hand, is behavior that is both in your best interest and other people’s best interest. It is not always possible to be moral, because some decisions may benefit only some people at the expense of the rest.

Sometimes, rationality and morality come into conflict, because the best thing for you may harm someone else. Should you be rational or moral? Since you are always concerned with your own interests (and only with the interests of others insofar as they are the same as yours), rationality comes first. Being moral is often valuable, but only when it is rational.

I think people are often more rational than they may seem, because sometimes they will pretend to be self-disinterested, and moral, as a strategy to serve their own interests. But much less often will they want to be seen as being rational when they are actually being moral.

But the situation is complicated because people often act in the best interests of their genes rather than in their own interests. Our interests are, of course, tuned by natural selection to be closely in line with the best interests of our genes. But they are not identical.

So there are at least two forces begging us not to be rational: 1) Moral forces, which demand that we be irrational in order to get along well with other people. People do not usually fall for this, but instead will just pretend to be moral while secretly being rational. 2) Genetic forces, which demand that we be irrational in order to support the survival of our genes. People fall for this all the time, because our genes have programmed us to turn off our rationality sometimes to protect our genes’ interests.

It’s always in your best interest to be rational. But sometimes we pretend not to be rational, in order to get along with others. And sometimes we genuinely won’t be rational, in order to support the survival of our genes. It seems society is less of a threat to us than our genes, unless you are susceptible to being brainwashed by society into being irrational.

References

• “Probability Theory: The Logic of Science” by E.T. Jaynes
• “The Selfish Gene” by Richard Dawkins

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