F.A. Hayek, The Road to Serfdom

There is nothing in the basic principles of liberalism to make it a stationary creed; there are no hard-and-fast rules fixed once and for all. The fundamental principle that in the ordering of our affairs we should make as much use as possible of the spontaneous forces of society, and resort as little as possible to coercion, is capable of an infinite variety of applications. There is, in particular, all the difference between deliberately creating a system within which compensation will work as beneficially as possible and passively accepting institutions as they are. Probably nothing has done so much harm to the liberal cause as the wooden insistence of some liberals on certain rough rules of thumb, above all the principle of laissez faire.

[Chapter One: The Abandoned Road]