This question gets at the heart of two very different philosophical approaches to ethical behavior. John Stuart Mill was a utilitarian. This means that he viewed actions that brought the greatest possible happiness, or utility, to the greatest number of people were ethical. Immanuel Kant, on the other hand, held that the motive behind an action made it ethical, irrespective of the consequences.

In the first scenario, you undertake an action that has clearly beneficial consequences in the sense that it increases everyone's happiness. Giving money to the man who obviously needs it makes him happy, it makes your partner happy, and it helps you by increasing your standing in your partner's eyes. However, the motive was not very pure—the only reason you did it was to impress your companion.

To a utilitarian, this is irrelevant. Everyone is happy, so what does the motive matter? To Kant, the act is not moral or ethical, because it is essentially a lie. He argued for what he called a "categorical imperative," which basically meant people should act as if what they were doing would be a generally accepted behavior for all mankind. Being dishonest or, in this case, acting from ulterior motives is probably harmless—indeed, it helps people. But because it is easy to imagine scenarios where dishonest acts might hurt people, it cannot be said, according to Kant, that this is an inherently moral or ethical act.

The second scenario, of course, is even more difficult. It is likely that either of these men could have found reasons to support or oppose the dropping of atomic bombs on Hiroshima and Nagasaki, an obviously horrific act on its face. Mill would have to be persuaded that the positive effects of dropping the bomb would have outweighed the negatives. If it is true, as military leaders argued at the time, that the decision to drop the bombs saved American and Japanese lives by averting a costly invasion of the Japanese homeland, then Mill would approve of it, albeit reluctantly, if no better scenario presented itself.

For Kant, again, the question would be about motive. If President Harry Truman made the decision to drop the bomb out of a sincere desire to avert more casualties than otherwise would have resulted, then the action could be defended. Indeed, we would hope that other world leaders would keep human lives in the forefront when they make decisions. If, however, Truman acted from ulterior motives, like, for example, domestic political concerns or out of a desire to frighten the Soviet Union, then it would be unethical.