I think it has more to do with habits of the mind. You need to be willing to explore and be inquisitive. You need to be able to read more difficult books (tha

I think it has more to do with habits of the mind. You need to be willing to explore and be inquisitive. You need to be able to read more difficult books (than entry level) like Let over Lambda or On Lisp and try to understand every sentence and every example and not just the superficial side but also as questions like why this way, when this is useful, what are limits on application, etc. I guess intelligence correlates but I know a lot of very intelligent people who are too lazy to be bothered to understand things deeply. It would be fair to say you need at least some IQ to be able to do this. Probably about 100-110 is a limit below which people just are not able to understand complex abstractions (which is a little scary if you think about it, because that is over half of the population). But I wouldn't say you need to be very intelligent (like 140 and upwards).