Our intelligence could just as well be a complicated mesh of a huge number of 'rules' that have evolved over a long period of time in response to many difficult situations that had threatened the survival of our ancestors. They are also what we call intuition/pre-born knowledge/natural tendencies and reflex responses.
Having said that, we have not ruled out the possibility of intelligence (albeit of a form different than ours) arising as an emergent phenomena from simple rules. But if we were to replicate human intelligence on silicon, I'm more inclined to believe that we'll have to 'manually' encode a huge number of situation-specific rules, e.g. when you see wriggly thing run away.