> Almost all evidence we have is that relevant aspects of human intelligence are environmental, ie., acquired. There is little evidence of the alternative becau

> Almost all evidence we have is that relevant aspects of human intelligence are environmental, ie., acquired. There is little evidence of the alternative because the experiments needed to establish it are large impossible or unethical. The experiment raising an infant chimpanzee alongside a human infant has been done. To presuppose that human intelligent is categorically distinct from chimpanzee intelligence such that this experiment does not lend evidence to a genetic basis of variations in human intelligence is further than I would go. I presume that some amounts of variation in intelligence, as well as IQ scores, is due to factors that are neither directly genetic nor environmental, but are more random (such as cell division and post-fertilization DNA replication and rearrangements).