Real talers have the same existence that the imagined gods have. Has a real taler any existence except in the imagination, if only in the general or rather common imagination of man? Bring paper money into a country where this use of paper is unknown, and everyone will laugh at your subjective imagination.

Marx, Doctoral Thesis, Appendix (1841)

Greek philosophy seems to have met with something with which a good tragedy is not supposed to meet, namely, a dull ending.

Marx,