Impossibility Results

[I]f ultimate values are incompatible, a perfect world in which all ultimate values—goodness, truth, justice, liberty, self-realization, equality, mercy, beauty—are combined cannot be conceived, let alone exist.

Thomas Mautner, The Penguin dictionary of philosophy, London ; New York, 1996, p. 68

Surely if we have learned anything from the history of morals it is that the thing to do with a moral quandary is not to hide it. Like nettles, the occasions when life forces us to choose between the lesser of two evils must be grasped with the consciousness that they are what they are. The vice of this use of the principle that, at certain limiting points, what is utterly immoral cannot be law or lawful is that it will serve to cloak the true nature of the problems with which we are faced and will encourage the romantic optimism that all the values we cherish ultimately will fit into a single system, that no one of them has to be sacrificed or compromised to accommodate another.

H. L. A. Hart, Positivism and the separation of law and morals, Harvard Law Review, vol. 71, no. 4, 1958, pp. 593, p. 33