Or how about this hypothetical definition. Reason is a complex type of instinct that has not yet formed completely. This implies that instinctual behavior is always purposeful and natural. A million years from now our instinct will have matured and we will stop making the mistakes that are probably integral to reason. An then, if something should change in the universe, we will all become extinct - precisely because we will have forgotten how to make mistakes, that is, to try various approaches not stipulated by an inflexible program of permitted alternatives.

Autor: Arkady Strugatsky