The theoretical source of many Jesus sayings in the Gospels of Matthew and Luke has long been considered a sure thing in New Testament studies. Most scholars writing about the Synoptic Gospels refer to "Q" (the first letter of the German word for source) without reciting arguments for its existence. Q itself, they've agreed, had as many as three possible stages of development, and Matthew and Luke independently drew from Q to supplement their likewise independent borrowing of Mark's basic narrative--or so goes the two-source thesis.

But a few scholars, mostly British, have proposed that Q is an artificial construct. They contend that Luke also knew Matthew's Gospel and borrowed creatively from it the many parables, admonitions and words of wisdom absent from the pioneering Gospel of Mark. Q was rebuilt by comparing Matthew and Luke, usually favoring Luke's sequence and wording as closest to Q's.

Now, in a book that mixes technical arguments with pleas to imagine another scenario, Mark Goodacre files a brief against Q that may force rebuttals and a restating of the case before new juries. A lecturer in New Testament at the University of Birmingham, Goodacre principally credits the work of Austin Farrer, who challenged Q in the 1950s.

The "Farrer theory," which has had its most energetic promoter in Michael Goulder, does agree with another consensus--that Mark was the first of the New Testament Gospels to be written. This distances the Farrer theory from the theories of other Q skeptics who contend that Matthew was first.

Goodacre says that just as Luke uses or reworks only those accounts in Mark he wishes to, he also selects only compatible episodes from Matthew: since Luke dislikes long discourses he shortens Matthew's Sermon on the Mount; Luke's attention to the poor causes him to change Matthew's "Blessed are the poor in spirit" to "Blessed are you poor." Goodacre rejects the view that the Gospel of Thomas is evidence that a text like Q existed. Q is understood as having "narrative properties," whereas Thomas is a true-sayings collection lacking geography and time-lines.

Scholars accepting Q's authenticity are at times pressed to explain why Matthew and Luke agree in their rewording of some episodes evidently borrowed from Mark. I'd be open to considering that Luke was influenced by Matthew or vice versa, or even that Mark very selectively used Q. But I'll take a seat in the courtroom before deciding whether defendant Q is just a straw man propped up in a chair.