I think that even most economists now reject the theory of the rational actor as a myth. Do lawyers still follow a version of this myth? Orin Kerr has a post about judging that makes me think he believes in rational judges.
Do judges really objectively observe these things called "facts" and "legal arguments"? Is there any empirical support for the position that judges rationally weigh legal and factual arguments? And that one's biases, background, and perceptions don't inform how judges view facts and arguments?
If so, I would like to see this research, as it would be a ground breaking refutation of David Hume's theory of practical reason!