autos epha » auto cephas = car Peter
Cephas is Aramaic and Petros (Peter) is Greek for rock.
The Pythagoreans used the phrase autos epha “he himself (Pythagoras) said it” as a way of punctuating their statements or proofs. The strict rules in the Pythagorean society included an unquestioning reverence of Pythagoras and use of the phrase autos epha served to cut off debate. Source: http://www.mlahanas.de/Greeks/PythagorasStar.htm
While ipse dixit (Latin translation of the Greek autos epha) and QED are in one sense both flourishes to a proof, their usage is not the same. One of my favorite sites http://wordsmith.org/ has a nice forum discussion on this.
Ipse dixit has made its way into legal terminology where it is used to indicate that the only proof of a stated fact is the word of the person who said it.
The Latin phrase spawned the somewhat pejorative term ipsedixitism used in logic.
“He brought him to Jesus. Jesus looked at him and said, "You are Simon son of John, you shall be called Cephas", which is translated 'Peter'.” (John 1:42)
The debate between some Catholic and Protestant scholars over whether the translation of Cephas (Petros) should be “big rock” or “little rock” and the importance of this distinction towards supporting (or not) the authority of the Pope is suspiciously reminiscent of Swift’s “big-endians” and “little-endians”.