"When we see a woman bartering beauty for gold, we look upon such a one as no other than a common prostitute; but she who rewards the passion of some worthy youth with it, gains at the same time our approbation and esteem. It is the very same with philosophy: he who sets it forth for public sale, to be disposed of to the highest bidder, is a sophist, a public prostitute."
January 1, 1970
https://en.wikiquote.org/wiki/Prostitution