[zifpanachr23]

Surely at some point higher IQ (in the IQ test sense) must also be likely to reach a point of diminishing or even negative returns.

I'm unconvinced that if everybody suddenly woke up tomorrow with an IQ score that was 20 points higher, that all of the most pressing issues in the world would start to be solved. Maybe some would, but I suspect we'd find out that there are tradeoffs that occur when we min/max a particular form of intelligence. There are also raw physical limits to contend with. The speed of light will remain a limit no matter how high your IQ. So there may be diminishing returns to science as well.

There are all sorts of ethical and social and game theory related problems that don't seem like they would be at all helped out by having a radically more analytically competent populace. If anything, I suspect we may be worse off.