Last Wednesday, I posted a link to a fascinating discussion of how many ancestors the average American of European descent would have had in the Middle Ages. The answer was all of them who have living descendants today. Those who missed it should read it. It's fun.
What I've been thinking about it what this means for the common claim that Matthew and Luke's genealogies of Jesus are contradictory. I guess the assumption of that claim is that there's only one genealogical path between and two people who have the ancestor/descendant relation. Given the common Hebrew practice of including certain ancestors in a list and not others, sometimes for theological purposes (e.g. 14 generations as a multiple of 7, the desire to show legitimate kingship, or emphasis on Gentiles and sinners in the ancestry), these two facts alone could explain why there could be two genealogies that are so different. The common responses by evangelicals to this issue deal with some specific issues (e.g. Levirate marriage with a biological father and a legal father), but I've always thought that they missed this obvious general point.
It's always struck me as strange that Matthew, who spends so much time explaining old covenant fulfillment in Jesus as Messiah, would make up a genealogy, or anything for that matter. Similar, it would be a little odd that Luke, who made such a great effort to investigate matters (Luke 1:1-4), would have made it up. If the traditional authorship is right, Luke would have had access to Jesus' brother Judas and could have checked on some of it, and Matthew would have known Mary even. I'm aware that many modern scholars reject the only reliable witness we have to who put these gospels together, so they dodge this point, but that's just poor historical method.