I was reading Kant's book "The Metaphysical Elements of Justice", when I saw that the great philosopher had discussed a common thought experiment in philosophy. A guy is on the Titanic as it sinks. He notices that there is only one spot left in a lifeboat, but another man who would take the seat. He can throw the other man into the ocean, murdering him, to procure himself a seat. Assume here that there is no risk of anyone else seeing him. We can modify the situation by replacing one of the men with a woman and her kids, to show that one side has a utilitarian advantage.

In either case, Kant has a clever solution. He says that a law is a necessary obligation for maintaing a civil society and an external incentive to that obligation. Kant argues that there is no external incentive that would dissuade someone from saving their life in such a circumstance, and thus the situation is outside of the justice system.

This has always been a sticky issue for me that has made me reluctant to accept a deontological ethical system. When people have said that "Lying is always wrong", I've thought of the situation of a Jewish person trying to escape from the ghetto - only able to do so if they lie to the SS. Are we really to say that the Jewish person is not morally justified in lying? One could say that this situation is an exception to the rule, but if we are to grant exceptions like this, then we might as well become utilitarians.

Kant's answer is nice and eloquent. Reading his text has been a joy and I look forward to getting my hands on A Critique of Pure Reason as soon as I can.