Arkady and Boris Strugatsky. Roadside picnic (№ 24012)

The mind is a complex instinct, has not yet formed completely. Have in mind that instictivly activity is always purposeful and natural. A million years from now our instinct will have matured and we will stop making mistakes that are probably inherent property of mind. And then, if in the Universe to change anything, we happily become extinct - again, precisely because we have forgotten how to make mistakes, that is, to try different, not predusmotrenny hard program options.