[Gobitron]

The Theory of Evolution does not say this. In fact, the Theory is predicated on the existence of randomness and adaptation. What you're suggesting is that every behavior has a reason for existence, which is almost the opposite of the Theory of Evolution.

[jrs99]

Where else would a behavior come from if it weren't purely molecular? The reason for a behavior might be that it is from a random mutation that even survived by random chance.