The study of IQ (and the underlying g) is one of two or three (definitely less than 6) crown jewels of psychology. You should probably read the actual science, "we" know quite a bit about intelligence. (I can help get you started if you're really interested, but I suspect you aren't.)

Thank you, I am indeed interested and I do read the actual science as you suggest. I study artificial intelligence so I'm in a position to know that there is no universally accepted definition of intelligence, certainly not a formal one that would allow us to encode it in a program and so reproduce intelligence in a machine.

There is very little disagreement on that in the field of AI. In fact, there is so much agreement that we have no idea what intelligence is, that we've totally given up on trying to understand it and instead switched to hoping that intelligence will naturally arise if we create complex enough systems (complex enough that we also don't understand them very well).

All that said, you're welcome to point me to the studies that are relevant to your field and I will gladly go through them, although I can't guarantee that I have the time to do so on time to continue this debate in this thread.

Well, if you're looking for understanding that's good enough we can program it, then yeah, we don't understand it. Also I think there was a misunderstanding on my part, in that we know quite a bit about human intelligence (that is, g), but not so much about intelligence-in-general. I'd rather clear up any miscommunication before throwing citations at you -- is your disagreement that g is not a well-established thing which maps very well to any tests of general intelligence you can conceive, or that g is a useless predictor, or that intelligence as measured by g is non-hereditary, or that g isn't useful because it's not a specific module of the brain we can simulate in code or hot-swap with that part of a donor's brain?

People may still quibble, but I was under the impression the standard acceptable definition for intelligence (at least among AI folks) is Legg and Hutter's informal "the ability to efficiently achieve goals in a wide range of domains". (Which has been formalized with AIXI.) I'm also aware of several groups in the AI field who believe they can actually construct a mind, in fact that this is the safest way forward, and that hoping it just "emerges" is folly as old as the first neural net proponents...