"Any simple major enhancement to human intelligence is a net evolutionary disadvantage."

--Eliezer Yudkowsky, Algernon's Law

Named after Algernon, the mouse from the novel Flowers for Algernon, written by Daniel Keyes Moran, states that human intelligence is at its optimal level. Not maximal, but optimal for our survival. If the human race would benefit from a higher intelligence, evolution would already have given us that. The negative side-effects of a higher intelligence might be visible and easily understandable - the difference between the 'smart' and the 'stupids' might make social interaction difficult - or hidden somewhere in some master thesis in neurology not yet written, like the causality between poor Algernon's superior intellect and its accompanying flaw.