Thoughts and ideas are not phantoms. They are real things. Although intangible and immaterial, they are factors in bringing about changes in the realm of tangible and material things.
Ludwig von MisesWhat impels every man to the utmost exertion in the service of his fellow man. Is, in the market not compulsion on the part of gendarmes, hangmen and penal courts, it is self interest.
Ludwig von Mises