The foundation of entrepreneurship and demand theory is the value of goods. "We do not desire things because we grasp in them some mystical, incomprehensible essence "value"; rather we ascribe "value" to things because we desire them." Christian von Ehrenfels, 1897.

Ehrenfels was a student of Franz Brentano and Alexius Meinong at the fuzzy boundary between philosophy and the new discipline of psychology in fin de siècle Austria. Ehrenfels was deeply affected by the early Austrian economists, as was Meinong — who took Menger’s seminar.

The boundary between Austrian economics and Austrian philosophy was highly permeable in both directions, because of a shared foundation in subjectivism and action & rejection of classical value theory. Ehrenfels took Menger’s subjective valuation of goods and extended to ethics.

And Menger, Wieser, and Böhm-Bawerk corresponded with Brentano, Meinong, and Ehrenfels until their deaths. The consequences of this scientific conversation are visible in Hayek and Mises, as well as @PerBylund.