Intelligence. How?

Question from Chan:
How does chance and random variation create human intelligence with all its “design capabilities”?

If evolution is driven by chance and necessity does it mean that human intelligence is merely an illusion?

Answer by SmartLX:
If evolution were purely a matter of random variations, it wouldn’t produce anything useful. Fortunately for us there’s a second major element, and it’s the one Darwin figured out: natural selection. Out of all the mutations in a given species (and, for instance, each new human has about 120) the ones which are actually useful become the most persistent in future generations, simply because they help their hosts to survive and procreate a little better than their peers.

It’s like dispatching a thousand people to search a ruin for treasure; most of them might find nothing, but when one guy turns up a gold coin more of the people will search in that area. It’s a highly inefficient process, but it can afford to be because evolution has had billions of years and trillions of individual life forms in which to work.

As for human intelligence, it’s a natural extension of the intelligence we see in dogs or apes. Dogs can learn jobs and tricks, and some apes can even make tools so “design capabilities” are not unique to humans. Smarter creatures generally work out ways to survive and outdo their competitors, so for any creature with a brain there’s some upward “selection pressure” on intelligence. After hundreds of millions of years of competing animals, it’s not so surprising that an animal as intelligent as homo sapiens has emerged.

There are some philosophical ideas that everything is an illusion, but intelligence is no more illusive than any other abstract concept of a physical quality, because it has effects in the real world. It can be tested, for example with IQ tests (which test very limited areas of intelligence, but still). There are things only animals of a certain level of intelligence can do, like recognise themselves in a mirror. We have a set of criteria which will allow us to acknowledge when computers achieve artificial intelligence, though these have not yet been met. Anyway, the process that produced intelligence in natural creatures is irrelevant to whether it’s a real thing now. There’s enough evidence that it is.