The link above is to a BBC news article about how the ethics of Immanuel Kant is being taught at West Point military academy to the future officers of the American armed forces.The course is taught by focusing on a simple moral thought experiment, where people theorize whether it would be better to let five people die, or deliberately bring about the death of one person. The West Point version takes it even a step further, asking if people would feel comfortable pushing someone onto the train tracks to save people's lives.
The article reports that people usually responded that they would act in the first case, but not in the second. The ridiculous nature of the difference is apparent only when we consider that there is no real difference in the question; both require that we make an action that will bring about the death of another person. The only difference is the emotional and physical distance between the action and the death.
The emotional difference is in the case of simple switch we can disassociate ourselves with the consequences; we flip switches frequently, there is no strong correlation to homicide. The push, however, necessitates that we must touch the man, and with our hands, bring about his demise. There is a primal connection between things we touch and ourselves.
The physical difference is one of effectiveness. Due to the constraints of the experiment, we are forced to conclude that the first exercise is completely effective, in flipping the switch we are saving the five people, no question. But in the second situation, there is some confusion. We are asked to believe that a human body dropped on the tracks, (even a purportedly "fat man" which is a whole other issue for size-ists) can stop a train. We must believe that he will drop properly, not fight back too vigorously, that no one will see us (the first as well, has the benefit that people watching a train accident are unlikely to be watching the person with the track lever, but people will always notice someone shoving another off a bridge.), and that he will even make a dent in the train inexorable progress toward the hapless victims.
How this relates to Immanuel Kant's theory is spurious. Kant's moral code was based on his first maxim; the categorical imperative. Without dwelling too long,the main notion is that a person must always do what is right (what he calls "the duty") without quibbling, motivation, error, or judgement. It expands further from there to explore what is right, thus enabling the actor to discern what is it he must do without fail. There are two further maxims to define the "right" and they run precisely thus: One must always act as though one's actions were brought into universal law, One must never treat other's as a means to an end, but only as an end in themselves. Functionally what he is saying is we must never act in a way that should everyone act as we do, we would not be happy/productive/alive. For example, we must not lie, because if we all lied, no one would believe anyone. Then we must treat all other people as autonomous beings who control their lives, and have their own hopes and goals, and we must never use them to achieve our own ends.
Even a brief glance over the theory reveals why it is completely counter-instructive to not only the thought experiment but also to the military goals and method as well. Kant would certainly not approve of us killing a man to save five others, let alone using a man like a human shield to stop the train, which is most certainly outlawed by the third maxims. Kant theorizes that when something is wrong, like killing a person, it is always wrong, in every circumstance. A radical notion, certainly, but one must wonder what about it the Professors felt would be applicable to the soldiers.
The reason why it is counter-intuitive to the military ideals is that they train soldiers to not only push the "fat man" but occasionally to go stalk the fat man, break into his home, and drag him back to the tracks to kill him. They train the soldiers to believe they go overseas to protect their homeland, to protect many more people who could be hurt by the people they are asking them to kill.
This is not to say I agree or disagree with the military method. It is simple to point out that it is contrary to the ideals they are teaching. If they really wanted to help protect civilians, a more effective philosopher would have been Jean-Paul Sartre. His ideals on existential humanism, that we are precisely the sum of our actions, would show soldiers that if they do anything that is "wrong" they must live with themselves, aware of who they have become, making them accountable for their own actions which now hold greater repercussions than following orders or not following orders, and would likely be a better deterrent for bad behaviour than waving some nebulous "duty" in their faces.