Betts vs. Svendsen

John Betts recently "ran into" polemicist Eric Svendsen, who's been on a mission over the last year or two to prove that modern Catholic usage of the term "Theotokos" (literally "God-bearer", usually translated "Mother of God") points to Christological heresies on the Catholic's part.

I, for one, am befuddled by this sort of refusal to accord Mary a title which was historically given her specifically in order to "safeguard" the unity of Jesus' (divine) person, as John very aptly demonstrates. Maybe some of my Protestant friends in the blogosphere can help me understand this phenomenon.