Sophisme du Nirvana

The view that now pervades much public policy economics implicitly presents the relevant choice as between an ideal norm and an existing "imperfect" institutional arrangement. This nirvana approach differs considerably from a comparative institution approach in which the relevant choice is between alternative real institutional arrangements. In practice, those who adopt the nirvana viewpoint seek to discover discrepancies between the ideal and the real and if discrepancies are found, they deduce that the real is inefficient. [...]

The nirvana approach is much more susceptible than is the comparative institution approach to committing three logical fallacies—the grass is always greener fallacy, the fallacy of the free lunch, and the people could be different fallacy.

Harold Demsetz, "Information and Efficiency: Another Viewpoint", Journal of Law and Economics, Vol. 12, No. 1 (Apr., 1969), pp. 1-22.