 In a scientific question, evidence can be adduced on both sides, and, in the end, one side is seen to have the better case—or, if this does not happen, the question is left undecided.But in a question, as to whether this, or that, is the ultimate Good, there is no evidence, either way; each disputant can only appeal to his own emotions, and employ such rhetorical devices as shall arouse similar emotions in others ...Questions as to "values"—that is to say, as to what is good or bad on its own account, independently of its effects—lie outside the domain of science, as the defenders of religion emphatically assert.