|Physical appearance||Elderly, wearing a loincloth, described as tall and willowy.|
|Books||Pyramids, Small Gods|
Ibid is one of the Ephebian Philosophers encountered by Brutha and the Omnians during the events of Small Gods. Like his contemporaries, Xeno, Didactylos and others, Ibid is an amalgam of Roundworld counterparts from ancient history - mainly Greek philosophers. He wrote the Discourses and thus parallels Roundworld's Epictetus.
He is one of a crowd that disputes in taverns and coins aphorisms, axioms and paradoxes for money. An example is "Thesis plus antithesis equals hysteresis".
According to the Annotated Pratchett File this is a play on the central tenet of dialectical materialism, which was lifted (by Marx and Engels) from Hegelian philosophy: "Thesis plus antithesis yields synthesis".
The British Army has a variant: "Order plus counter-order equals disorder".
Also, in Roundworld, ibid., short for ibidem, 'the same place', is used in an endnote or footnote citation for a source cited in the previous endnote or footnote. This neatly ties in with the fact that Ibid 'thinks he's the biggest bloody authority on everything' and when Xeno is introducing all the philosophers to Teppic, he says "Well, Ibid you already know..."
This joke was also used by Illuminatus! author Robert Anton Wilson, when he created the greatest classical authority, Ibid of Anon.