"Exactly at the explanation. The conflict between the various rules is ironed out by the different positronic potentials in the brain. We’ll say that a robot is walking into danger and knows it. The automatic potential that Rule 3 sets up turns him back. But suppose you order him to walk into that danger. In that case, Rule 2 sets up a counterpotential higher than the previous one and the robot follows orders at the risk of existence."