Endos
As featured in Pyramids, Endos the Listener is a Philosopher. Or rather, he helps the other philosophers (such as Xeno, Ibid, Didactylos &c) by Listening to them. As they espouse their brilliant - or otherwise - theories, drunken rants and epithet-moulding discourses, whilst everyone else argues and disputes, Endos listens and murmurs encouragments such as "Fascinating!" or "Do go on!" For this essential service he is paid in small coin or amphorae of wine. Perhaps the only Philosopher he does not appreciate Listening to is Copolymer.
Because all thinkers need to be listened to. In fact, most of the major philosophers in Ephebe have accounts, and are periodically presented with their bill.