> A person with an 80 IQ, for example, would likely not be able to understand advanced philosophy or mathematics or some such at all -- even given infinite time.

Yes, I wanted to write similar thing too, but felt that post was too big already. Besides, I am not completely convinced by the idea itself - having enough memory, you can actually slowly link the most complicated concepts even when you can link only relatively "similar ideas" (brain of higher IQ has a tendency of creating longer physical neuron links, which some relate to the ability to understand seemingly unrelated concepts). The impossible part probably comes from the fact that the time and effort required would be inadequate.