"If one wants to know what liberalism is and what it aims at, one cannot simply turn to history for the information and inquire what the liberal politicians stood for and what they accomplished. For liberalism nowhere succeeded in carrying out its program as it had intended.

Nor can the programs and actions of those parties that today call themselves liberal provide us with any enlightenment concerning the nature of true liberalism. It has already been mentioned that even in England what is understood as liberalism today bears a much greater resemblance to Toryism and socialism than to the old program of the freetraders. If there are liberals who find it compatible with their liberalism to endorse the nationalization of railroads, of mines, and of other enterprises, and even to support protective tariffs, one can easily see that nowadays nothing is left of liberalism but the name.

Nor does it any longer suffice today to form one's idea of liberalism from a study of the writings of its great founders. Liberalism is not a completed doctrine or a fixed dogma. On the contrary: it is the application of the teachings of science to the social life of man. And just as economics, sociology, and philosophy have not stood still since the days of David Hume, Adam Smith, David Ricardo, Jeremy Bentham, and Wilhelm Humboldt, so the doctrine of liberalism is different today from what it was in their day, even though its fundamental principles have remained unchanged. For many years now no one has undertaken to present a concise statement of the essential meaning of that doctrine. This may serve to justify our present attempt at providing just such a work."

Ludwig von Mises
Liberalism