This thinker compares a physician curing a patient to a murderer poisoning a victim when contrasting the rule of skill with the happiness-based counsel of prudence. Helga Varden added a Nazi officer to an argument criticizing this thinker first made by Benjamin (15[2])Constant. (15[1])The employment of assassins would be banned and standing armies abolished in this thinker’s proposal for a (*) Perpetual Peace between republican states. This thinker claimed that lying to a man knocking on your door was not (10[1])moral even if you knew he was a murderer looking for a potential victim. This thinker’s ethical system centers on acting consistently with universal rules through the (10[1])categorical imperative. For 10 points, name this German philosopher who wrote Critique of Pure Reason. ■END■