“In God we trust; all others must bring data.” -W. Edwards Deming
But if once we begin to say how the production and distribution of wealth ought to be carried on we can no longer confine our attention to facts about wealth. We have to decide how far wealth is desirable, we have to compare wealth with other desirable objects. We cannot say that laisser faire should be our rule until we are agreed upon subjects which are quite alien to the science of wealth. Our economists should make their choice, either they must give up talking about what ought to be, or they must take into consideration ethical and political doctrines on which the methods of the science of wealth throw no light. Of all our writers on political economy the most successful have been those who have most constantly kept in view the fact that when the economist begins to justify and condemn, he has passed the bounds of his own special science, he has become a moralist, and must behave as such.
Friederic William Maitland, A historical sketch of Liberty and Equality, p. 129