One line of argument he made popular went like this. Jesus said that he was God. Jesus was neither a deceiver nor deceived. Therefore Jesus was indeed God. Mocking the idea that Christ was simply a great moral teacher, Lewis wrote that a man that said the sort of things Jesus said “would either be a lunatic – on a level with the man who says he is a poached egg – or else he would be the Devil of Hell”. Yet even most conservative biblical scholars today think it unlikely that Jesus in his lifetime made any explicit claim to divinity, so that the argument fails to get started.
Lewis’s trilemma argument does indeed have a serious weakness, and Kenny gropes towards it: Lewis’s argument depends on the assumption that the Gospels faithfully record Jesus’s words, but if you doubt the reliability of the Gospel accounts, then you can easily believe that Jesus was a “great moral teacher” who had certain words put in his mouth by later disciples. This is the assumption that underlies most skeptical redactions of the Gospels, from the Jefferson Bible to the work of the Jesus Seminar. But the great majority of biblical scholars today, as throughout the history of the Church, do indeed believe that the Gospels faithfully record Jesus’s teachings, which puts the trilemma into play.
While I agree with Jacobs that many (if far from all) biblical scholars hold that the gospels (or at least the synoptic gospels) faithfully record the spirit (if not the letter) of Jesus’ teachings, Lewis’s argument still faces some serious obstacles. The biggest problem, in my view, is that Lewis and those who follow him tend to read a full-blown doctrine of the Incarnation back into the gospel texts, and sometimes put questionable interpretations on ambiguous passages. Many of the proof-texts sometimes used to show that Jesus claimed to be divine are susceptible of much less exalted readings.
That said, I do think many contemporary scholars would accept that the historical Jesus claimed a special or unique role for himself in God’s unfolding plan. Many statements of Jesus in the gospels, while falling short of straightforward claims to divinity, do express the sense that one’s response to Jesus is determinative for one’s standing in God’s kingdom. This makes some on the liberal end of the spectrum uncomfortable, in part, I suspect, because it conflicts with the portrait of Jesus as a benevolent sage preaching a message of inclusive tolerance. (See the final chapter of Michael McClymond’s Familiar Stranger for a good discussion of this issue.) So if Jesus viewed himself as the agent of God’s inbreaking reign, even if he didn’t claim to be divine in Nicea-compliant terms, a modified version of Lewis’s trilemma argument could perhaps get off the ground.