It depends on the definition of "rational". A serviceable but vacuous definition is "the procedure by which a decision is reached." Note that it is vacuous in

It depends on the definition of "rational". A serviceable but vacuous definition is "the procedure by which a decision is reached." Note that it is vacuous in that it imposes no constraints (not even repeatability/consistency), so anything that results in a decision fits the definition. It is serviceable because if you want a better definition, you have to argue deviations/changes - eg consistency. You'll find it to be a choice, not a requirement. Eg: Batman's Joker behaves according to his rules. The end result may be unpredictable, but that doesn't mean the decision process doesn't follow his rules.