In Mere Christianity, C. S. Lewis writes this about Jesus (emphasis mine):
I am trying to prevent anyone saying the really foolish thing that people often say about Him: "I am ready to accept Jesus as the great moral teacher, but I don't accept His claim to be God." That is the one thing we must not say. A man who was merely a man and said the sort of things Jesus said would not be a great moral teacher. He would either be a lunatic - on a level with the man who says he is a boiled egg - or else he would be the Devil of Hell. You must make your choice. Either this man was, and is, the Son of God: or else a madman or something worse. You can shut Him up for a fool, you can spit at Him and kill Him as demon; or you can fall at His feet and call Him Lord and God. But let us not come with any patronizing nonsense about His being a great human teacher. He has not left that open to us. He did not intend to.
This argument is bogus because Jesus didn't claim to be God.
Three separate email correspondents of mine have used this argument to counter my assessment that Jesus was a wise prophet whose moral imagination has helped establish egalitarianism, moral relativism, and humanism in Western civilization. I take that experience to mean that Lewis’s argument still has a currency that it doesn’t deserve.
Lewis wants you to choose among Jesus being a madman, the Devil of Hell, and God. After all, how wise could someone be if they claim to be God but aren’t? Lewis fails to see the fourth possibility. What about the people who say, "I am ready to accept Jesus as the great moral teacher, but I don't accept the claims the Christians make that He is God"? Lewis assumes, without demonstrating it, that Jesus claimed to be God. If Jesus never claimed to be God, Lewis's argument is baseless. Christians might affirm that Jesus is more than a moral teacher, but Lewis’s argument doesn’t demonstrate that it’s “foolish” to regard him as such.
Before we start, it’s important to note that Lewis’s argument, strictly speaking, doesn't rely on the gospels being true. One can’t use the veracity of scripture to prove Lewis’s point. If you’re going to presume the veracity of scripture, then Jesus’ divinity is already proved and Lewis’s argument is empty. In the strict sense, that would be begging the question. Lewis’s argument has substance only to the extent that it makes its case without presuming that scripture is true. If a Christian wants to argue that Jesus was God because scripture says so, that’s fine, but that’s not Lewis's argument.
But aren't the gospels God's Word? Not according to the Bible itself. The Bible never defines the gospels as God’s Word. Jesus didn't write the gospels. He didn't tell anyone to write them. He didn't prophesy that they'd be written or tell anyone to believe them. The Bible never says that the gospels are the Word of God. Christians wrote lots of gospels, chose four from among them, assembled them, and declared them the Word of God. But there’s nothing self-contradictory or foolish about nonchristians having their own opinions about the veracity of scripture.
Once we see that Lewis’s argument has to stand on its own without relying on scripture, we’re practically done refuting it. Lewis’s statement that Jesus claimed to be God is based on scripture, and once one can question scripture, there’s not much to it. Even if the gospels portrayed Jesus as claiming to be God, that wouldn't prove he actually did. But if I want to say that Jesus was a wise teacher, I do have to give at least some credence to scripture. After all, that’s where I get the idea that he was a wise teacher. So let’s see if we can get past the idea that Jesus claimed to be God without tossing scripture out wholesale.
Claim to be God
Don't the Gospels quote Jesus as saying that He was God? It’s this understanding that’s the foundation of Lewis’s argument. Is it true? This turns out to be a tricky question. To the surprise of some Christians, Jesus never comes out and lays it on the line. In fact, in the synoptic gospels he's reticent about being the Anointed One (Messiah), let alone God. There’s a term in Christian scholarship for this reticence: the Messianic secret. Willian Wrede came up with this phrase in 1901, and he wrote that the "secret" was Mark's way of accommodating the historical fact that Jesus jad never made the claim in the first place. But there are two plausible scenes where Jesus might be claiming to be God: when he’s talking about Abraham and when he’s at the council of chief priests. Neither of these instances, however, is ironclad. The Jesus Seminar, for example, rejects them both.
In the gospel of John, Jesus says, “Before Abraham was, I am” (8:58). Christians looking for a claim for divinity use this one, with the idea that “I am” is a clear reference to the divine name, YHWH. But when God tells Moses his name, he says, “He will be that will be.” It’s not clear to me that “I am” in Aramaic and “He will be that will be” in Hebrew are really the same. But even if we grant that Jesus is claiming to be God in this scene, we are not beholden to take it at face value. Remember, Lewis’s argument is only worthwhile if it does not depend on the veracity of scripture. The gospel of John is the only gospel that identifies Jesus as a god, identifying him as the divine Word, the True Vine, etc. If we want to believe that Jesus never claimed to be God, it’s pretty easy to discount one scene from a text written by a strong advocate of the view that Jesus was divine.
As to Jesus answering the high priest (Mark 14: 61-62), when asked whether he was "the Christ, the Son of the Blessed," Jesus reportedly said, “I am.” Even if we accept this line as an actual claim to divinity (that it’s like saying “I’m YHWH”), there’s no reason to believe that Jesus said it. This is Jesus talking to the high priest while the disciples are elsewhere. How did the author of Mark know what Jesus said? In fact, the gospel of Luke (22:70) reports Jesus saying something else: "You say that I am." Christians will say that the gospel writers were inspired by the Holy Spirit, but once you presume that scripture is divinely true, then you don’t need Lewis’s argument. Lewis’s argument is that the idea of Jesus as a moral teacher is foolish because he claimed to be God, not because scripture is true.
The sayings that modern scholars say can reliably be attributed to Jesus are generally those that he made in public and that more than one gospel reports, such as several of the the Beatitudes, the parables, the Golden Rule, etc. Jesus’ supposed claims to divinity are not on such firm footing.
In Matthew 17: 1-8, Jesus is "transfigured" and God in Heaven calls him His Son. But only three disciples see the transfiguration: Peter, James, and John. Why only three? Why not in front of thousands of people? Why are there no accounts of Jesus telling people about the transfiguration? Maybe because it never happened. It looks for all the world like a scene invented after the fact in order to bolster the assertion of some disciples that Jesus was the Son of God.
Jesus apparently called himself "son of God," perhaps because he had been "born again" when John the Baptist baptized him. Early Christians took the phrase rather too literally, and then they mistranslated Isaiah 7:14, and the story of the Virgin Birth was born. The story of the Virgin Birth seems to be another Christian idea that originated with Zoroastrianism, along with the Devil and Judgment Day.
And even being the Son of God is not the same as being God. Jesus himself quotes Psalms and says to the Jews, “You are gods, sons of the most high, all of you.” If the Jews can be the sons of the most high without being God, Jesus can, too.
Claims to Special Spiritual Status
But didn't Jesus claim to be the Christ? And the Messiah? And the Son of Man? Sure, but these are not the same as God. Christ/Messiah (“Anointed”) were terms for the righteous king who would restore Israel, or some similar holy mortal. The “Son of Man” is an obscure term from Daniel, and it often seems to be used in its plain sense as “human being." The gospels sometimes have Jesus use the term to mean a divine judge from heaven, but when he does he's talking about someone besides himself. Christians associate the term “Son of Man” with “Christ, the incarnation of God,” but that meaning is not in the text.
Claim to Divinity
Starting very early in the history of the church, Christians claimed increasingly divine identities for Jesus. At first this was limited to his being the image of God, the perfect revealer of God, and the firstborn of all creation. To differentiate orthodox beliefs from gnostic beliefs, which allowed multiple divine emanations, Christ was defined as closer and closer to God until, in the 300s, the bishops agreed that he was indeed fully God.
But the outlandish beliefs of Christians about Jesus don’t disqualify Jesus from having been a wise teacher. Christians recorded accounts of Jesus possibly claiming to be God, but modern scholars do not trust early Christians to be totally accurate. Lewis’s argument works only because it doesn’t acknowledge the option that one can believe some of the gospel accounts without believing every word of them. Lewis’s popluar syllogism, which apparently goes back to Pope Innocent III (circa 1200) and has been championed by apologist Lee Strobel, is without merit.