by Ludwig von Mises (transcripts of lectures from 1952):
THE FIRST FIVE LECTURES IN THIS SERIES will be on philosophy, not on economics. Philosophy is important because everybody, whether or not he knows it, has a definite philosophy, and his philosophical ideas guide his actions.
The philosophy of today is that of Karl Marx [1818–1883]. He is the most powerful personality of our age. Karl Marx and the ideas of Karl Marx—ideas which he did not invent, develop, or improve, but which he combined into a system—are widely accepted today, even by many who emphatically declare that they are anti-communist and anti-Marxist.To a considerable extent, without knowing it, many people are philosophical Marxists, although they use different names for their philosophical ideas.
In a later lecture:
It is impossible to defeat a philosophy if you do not fight in the philosophical field. One of the great deficiencies of American thinking—and America is the most important country in the world because it is here, not in Moscow, that this problem will be decided—the greatest shortcoming, is that people think all these philosophies and everything that is written in books is of minor importance, that it doesn’t count. Therefore they underrate the importance and the power of ideas. Yet there is nothing more important in the world than ideas. Ideas and nothing else will determine the outcome of this great struggle. It is a great mistake to believe that the outcome of the battle will be determined by things other than ideas.
This could have been written by Ayn Rand (who was the best advocate of the importance of philosophy).