Over the weekend I read A. Roy Eckardt’s Reclaiming the Jesus of History: Christology Today. The book is more interesting than the title suggests; Eckardt writes in conversation not only with “historical Jesus” studies, but also with feminist theology, theology of religions, liberation theology, and particularly “post-Shoah” theology. His stated goal is to develop a Christology that maintains the distinctiveness of Christianity without adopting a triumphalist or supersessionist stance toward other traditions (preeminently Judaism).
In Eckardt’s view, the historical Jesus is indispensable for any viable Christology. This doesn’t mean that the content of Christology can be completely determined by historical study. Rather, Eckardt adopts what he calls a “Lockean” view of the matter, based on an analogy with John Locke’s position on the relationship between faith and reason. Locke’s view was that religious truth can be based on reason or go “beyond” reason, but it can’t contradict reason. Likewise, Eckardt says, theological truth can be based on history, or go “beyond” history, but it can’t contradict history.
What’s the practical upshot of this? Well, here’s a pertinent example. Since we know that the historical Jesus was a faithful Jew who never broke with the tradition of his ancestors, any Christology that would imply that God’s covenant with Israel has been nullified or superseded would be automatically suspect. The Jesus of history, in this view, provides a kind of negative criteria for judging theological constructions.
A Thinking Reed 
That seems a little dubious to me; after all, the Jesus of history never baptized Gentiles, either.
I think he would employ the distinction between “goes beyond” and “contradicts.” Including gentiles in the community of God’s people, arguably, is an extension of the eschatological hopes of Judaism. By contrast, claiming that Judaism has been superseded by Christianity is contradicted by the life of the historical Jesus.
I’m not sure I’d go to the mat for this “rule”–at least the way Eckardt formulates it–but I do think the historical Jesus has to play some regulative role in Christological thinking.
“Thus he declared all foods clean” sounds like a clean break to me. (But I don’t mean to nitpick)
Hey, pick away! (But do you think that verse indicates Jesus breaking with Judaism?)
Good point. Plenty of Jews don’t keep kosher.