Page:Ethics (Moore 1912).djvu/86

 Now I think that most of those who hold, as this theory does, that one and the same action cannot be both right and wrong, simply assume that this is the case, without trying to prove it. It is, indeed, quite common to find the mere fact that a theory implies the contrary, used as a conclusive argument against that theory. It is argued: Since this theory implies that one and the same action can be both right and wrong, and since it is evident that this cannot be so, therefore the theory in question must be false. And, for my part, it seems to me that such a method of argument is perfectly justified. It does seem to me to be evident that no voluntary action can be both right and wrong; and I do not see how this can be proved by reference to any principle which is more certain than it is itself. If, therefore, anybody asserts that the contrary is evident to him—that it is evident to him that one and the same action can be both right and wrong, I do not see how it can be proved that he is wrong. If the question is reduced to these ultimate terms, it must, I think, simply be left to the reader’s