Cultural evolution versus rational thinking

Previously: Truth versus utility

The rarity of suicide and the rarity of anti-natalist belief are good examples of the unimportance of argument. People who commit suicide have fewer children; suicide (during reproductive age) is selected against more strongly than perhaps anything else in life. I find David Benatar's arguments in "Better Never To Have Been" compelling, but almost nobody else does. Perhaps the arguments are bad, but regardless, a predisposition to believe them is selected against. Some people are literally incapable of believing them. I don't just mean stupid people, who are incapable of comprehending them, and benefit from this inability. The inability to believe something can be beneficial to people regardless of intelligence.

Cultural evolution doesn't work by selection of inherited "particles" of culture (memes as "units" of culture don't exist). Nevertheless, cultural evolution clearly happens, for example languages have evolved (there is a family tree of languages).

In "The Fatal Conceit", Hayek makes an evolutionary argument for how people invent their traditions and practices. People don't invent them deliberately by careful argument; rather the practices evolve because they benefit the people who carry them out. Hayek uses the word "tradition" but "practice" might be better. Hayek points out how much of human action is unthinking, automatic, traditional: "rationalists" may try to optimize their actions through introspection and argument, but they miss 99% of what they do.

In evolution, reasons and designs exist but not necessarily in anyone's mind. Daniel Dennett calls them "free-floating rationales". It can be difficult or even impossible to work out what they are. There are numerous "paradoxes" in evolution, where no one knows why something evolved, but we presume there must be a good reason.

Hayek uses his evolutionary argument to argue against socialism and central economic planning. This argument is difficult to make, because it is inevitably unconvincing even if it is true. It is unconvincing to say "it must be good to do things this way, but we don't know why": people demand evidence a particular practice is good. People are not used to applying evolutionary arguments to politics.

Religion is an excellent example, because we know the outcome is good -- religious people have more children -- but we can't explain how it works. Religion may seem an irrational, boring waste of time, but it is not.

Richard Dawkins invented the idea of memes to explain religion. He portrays religion as a parasite, which hijacks humans like a virus, to spread its ideas. Many religious ideas are highly optimised to spread, and to resist careful examination for truth. However, Dawkins completely fails to engage with the fact that religion is good for human fitness. Religious people have more children. Therefore, religion is not a parasite but a symbiote.

In David Sloan Wilson's book "Darwin's Cathedral", Wilson argues that religion benefits the group because it promotes cooperation. Someone is less likely to defect in private if they think God is watching them.

We co-evolve with our beliefs and practices. In the example of religion, as religion evolves to benefit us, we evolve a capacity for religion. In the example of anti-natalism, we evolve to be unable to believe something.

Inductive versus probabilistic reasoning

Deductive arguments have a poor track record. Even if the argument is sound, the premises may be wrong, or the argument may not map well to the real world.

But inductive reasoning does not much appeal to deductivists. It sounds wishy-washy and doesn't produce the certainty that deductive reasoning appears to give. This is because so-called inductive reasoning is not how most people reason in the real world.

The classic inductive argument goes: The sun has risen 100 times before, therefore it will rise again tomorrow. Expressed in deductive terms, the implicit inductive premise is "if something has happened a lot in the past, it will probably happen again tomorrow". That's reasonable, but the key word is "probably". So the argument would be better expressed as "The sun has risen 100 times before, therefore it will probably rise again tomorrow." If we make the argument stronger "The sun has always risen before, therefore it will definitely rise again tomorrow", that's false.

The problem with this sort of reasoning is, like Laplace's rule of thumb, it ignores our detailed knowledge about the world. Like Laplace's rule of thumb, it's just a rule of thumb.

If the sun has risen a thousand times before, we do not just estimate the probability of it rising tomorrow as one in a thousand. We can be much more confident, because we understand that "sunrise" is a term for the sun moving above the horizon, as the earth orbits the sun in a solar system. For the sun to fail to rise tomorrow, something extraordinarily improbable would have to happen. For example, the sun would have to explode, in a way we did not predict.

In practice, we can use our knowledge about the sun to predict that it will engulf Mercury & Venus, and render Earth uninhabitable, in about five billion years.

Inductive reasoning should be replaced by probabilistic reasoning.