Who is Jesus?
What is Jesus?
How do you know about Jesus?
C. S. Lewis popularized the argument that Jesus was either a liar or a lunatic or the Lord. But, as Kyle Barton has shown, he didn’t invent it.
In the mid-nineteenth century the Scottish Christian preacher “Rabbi” John Duncan (1796-1870) formulated what he called a “trilemma.” In Colloquia Peripatetica (p. 109) we see Duncan’s argument from 1859-1860, with my numbering added:
“Christ either  deceived mankind by conscious fraud, or  He was Himself deluded and self-deceived, or  He was Divine. There is no getting out of this trilemma. It is inexorable.”
In 1936, Watchman Nee made a similar argument in his book, Normal Christian Faith. A person who claims to be God must belong to one of three categories:
First, if he claims to be God and yet in fact is not, he has to be a madman or a lunatic.
Second, if he is neither God nor a lunatic, he has to be a liar, deceiving others by his lie.
Third, if he is neither of these, he must be God.
You can only choose one of the three possibilities.
If you do not believe that he is God, you have to consider him a madman.
If you cannot take him for either of the two, you have to take him for a liar.
There is no need for us to prove if Jesus of Nazareth is God or not. All we have to do is find out if He is a lunatic or a liar. If He is neither, He must be the Son of God.
C. S. Lewis, speaking in 1942 (and published in Mere Christianity in 1952), gave the argument its most memorable formulation:
“I am trying here to prevent anyone saying the really foolish thing that people often say about Him: I’m ready to accept Jesus as a 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 the level with the man who says he is a poached 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 a demon or you can fall at his feet and call him Lord and God, but let us not come with any patronising nonsense about his being a great human teacher. He has not left that open to us. He did not intend to. . . . Now it seems to me obvious that He was neither a lunatic nor a fiend: and consequently, however strange or terrifying or unlikely it may seem, I have to accept the view that He was and is God.” (Mere Christianity, 55-56)
Is this a good argument?
The argument can be formulated as follows:
If Jesus were not Lord, he would be a liar or a lunatic.
Jesus was neither a liar nor a lunatic.
Therefore, Jesus is Lord.
To determine whether this argument is sound, we have to ask three questions:
Are the terms clear?
Is the logic valid?
Are the premises true?
I would give the following answers:
Yes, the terms are clear.
Yes, the logic is valid; premise 3 follows from premises 1 and 2 based on the rules of logic (Modus Tollens: the negation of the antecedent of premise 1 can be inferred by the negation of its consequent).
But no, the argument is unsound, because not all of the premises are necessarily true. As William Lane Craig points out in Reasonable Faith, the first premise leaves out other possible options and is therefore false. There is another alternative: perhaps the Jesus presented in the Bible is not the true Jesus of history. The Jesus of the Bible may not be a liar or a lunatic or a Lord but rather a legend. In other words, the Jesus of the Bible is not the Jesus of history, so your claims about what must be trust about the Jesus of the Bible do not lead to conclusions about the actual lordship of the Jesus of history.
But C. S. Lewis can help with the rebuttal here.
In a 1950 essay, “What Are We to Make of Jesus?” Lewis works through some of Jesus’s startling claims about himself in Scripture, repeating his insistence that you can’t conclude that he was simply a “great moral teacher.” If what he said is true, Lewis says, then they are the sayings of a “megalomanic.”
“In my opinion, the only person who can say that sort of thing is either God or a complete lunatic suffering from that form of delusion, which undermines the whole mind of man. If you think you are a poached egg, when you are not looking for a piece of toast to suit you you may be sane, but if you think you are God, there is no chance for you. We may note in passing that He was never regarded as a mere moral teacher. He did not produce that effect on any of the people who actually met him. He produced mainly three effects — Hatred — Terror — Adoration. There was no trace of people expressing mild approval.”
It’s here that Lewis addresses the rebuttal that Jesus did not really say these things; his followers exaggerated the story and the legend grew that he really said these things. Lewis shows how unlikely it would be for the Jews to invent God become man:
“This is difficult because His followers were all Jews; that is, they belonged to that Nation which of all others was most convinced that there was only one God—that there could not possibly be another. It is very odd that this horrible invention about a religious leader should grow up among the one people in the whole earth least likely to make such a mistake. On the contrary we get the impression that none of His immediate followers or even of the New Testament writers embraced the doctrine at all easily.”
The other option is that the accounts of Jesus were written as legends. Here Lewis draws upon his scholarly expertise:
“Now, as a literary historian, I am perfectly convinced that whatever else the Gospels are they are not legends. I have read a great deal of legend and I am quite clear that they are not the same sort of thing. They are not artistic enough to be legends. From an imaginative point of view they are clumsy, they don’t work up to things properly. Most of the life of Jesus is totally unknown to us, as is the life of anyone else who lived at that time, and no people building up a legend would allow that to be so. Apart from bits of the Platonic dialogues, there is no conversation that I know of in ancient literature like the Fourth Gospel. There is nothing, even in modern literature, until about a hundred years ago when the realistic novel came into existence.”
So Lewis thinks it implausible that monotheistic Jews would have invented an incarnate Messiah and he thinks that the genre of the gospels bears none of the typical marks of legends—based upon a lifetime of scholarly and leisure reading of ancient legends. Therefore, the Jesus of the Bible is the Jesus of history. And if this one Jesus were not Lord, he would be a liar or a lunatic. But he is truthful (not a liar) and sane (not a lunatic). Therefore he is Lord.