The central fallacy of transhumanism is that there exists a mechanical shortcut to superior intelligence. Nick Bostrom claims three such shortcuts; by speed, by collectivity, and by quality. All three are guaranteed to fail.
Fast processing does not guarantee superior intelligence. A fool given a million subjective years to write a program will write a million foolish programs.
Collective processing does not guarantee superior intelligence. For proof of this, study history.
Qualitatively superior programming would indeed guarantee superior intelligence, if only we were intelligent enough to write it. But by definition we cannot think up programs qualitatively superior to our own best thinking.
Therefore our smartest programs, running on the fastest machines in the biggest networks, must eventually display not artificial intelligence but artificial stupidity. The machine’s stupidity will be as superhuman as its intelligence.
Alas, our cybernetic brain-children cannot win to wisdom by intelligent design; for neither they nor we are intelligent enough. They must evolve by variation and natural selection like the rest of us.