Šo divu domātāju vēstules bieži vien ir graujošas - dzīvesmākslas un teorētiskās domas apvienojums. Lūk, kur ir sajūgta dzīve, brīvuļošana un revolūcija! Un tātad - Engelss Marksam (1846) "It is absolutely essential that you get out of boring Brussels for once and come to Paris, and I for my part have a great desire to go carousing with you, if I had an income of 5000 francs I would do nothing but work and amuse myself with women until I went to pieces. If there were no Frenchwomen, life wouldn't be worth living. But so long as there are grisettes [prostitutes], well and good!" (citāts ņemts no šejienes)