Utilitarianism

The only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others. His own good, either physical or moral, is not a sufficient warrant. He cannot rightfully be compelled to do or forbear because it will be better for him to do so, because it will make him happier, because, in the opinions of others, to do so would be wise, or even right. These are good reasons for remonstrating with him, or reasoning with him, or persuading him or entreating him, but not for compelling him, or visiting him with any evil, in case he do otherwise.

-- John Stuart Mill (1806-1873), English political philosopher and economist, advocate of utilitarianism, On Liberty, Chapter 1 (1859)