Lewis’s trilemma

UPDATE: Thanks to the help of commenters, I’ve added some more options to the flow chart in this post (“Joker” and “Poet”). I’ve also tweaked one or two of the probabilities, and displayed the outcomes in a chart.


C. S. Lewis, in Mere Christianity, popularized an apologetic device concerning Jesus’ claim to be the son of God. Here it is in full:

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.

This has become known as Lewis’s Trilemma, because it offers us only three options. Jesus was either a lunatic, a liar, or “Lord”. It is not difficult to come up with further options that Lewis, for whatever reasons, left out of his argument. In the following flow chart, I’ve tried to expand the trilemma to cover the main options I think are available. Lewis’s three options are shown with green boxes.


All told, I come up with eight alternatives to “Lord”. Jesus’ claim could be the product of legend or, if he actually did make it, he might have been mistaken (out of ignorance or misinterpretation of the facts), coerced, lying, insane (mildly or severely), joking, or speaking metaphorically (“poet”).

Just for fun, I thought I’d assign what I think are likely probabilities to each branch in the flow chart.


The two probabilities for each YES-NO pair add up to 1. To work out the probability of a particular outcome, multiply the probabilities you encounter along the way. So, for instance, to find the probability that Jesus was a liar, we have to reject the legend option (probability 0.5), accept that he made the claim freely (0.95), that he was fully informed (0.9), but that he did not believe what he was saying (0.3), and he wasn’t using humor (0.9) or metaphor (0.3). The probability that he was lying is therefore 0.5 x 0.95 x 0.9 x 0.3 x 0.9 x 0.3 = 0.0346, or 3.46%.

Here is a chart showing the probability of each possible outcome.


For the math geeks: The above probabilities sum to 1 as they should.

Obviously the above probabilities shouldn’t be taken too seriously, although I think they are at least in the right ballpark. The point is that Lewis’s trilemma was quite obviously simplistic – a great example of the false dilemma fallacy (extended to a trilemma of course).

There is another problem with Lewis’s Trilemma. It uses extreme language to trigger an emotional response. Although I’d like to think that Lewis had a reasonably compassionate attitude toward the mentally ill, he certainly doesn’t show it in this apologetic, likening the “lunatic” option to a man who calls himself a poached egg.

Lewis is hoping that his reader will be so aghast at the notion of a “lunatic” Jesus (cue images of someone bouncing off the walls of a padded cell, screaming paranoid nonsense) that the idea will be instinctively rejected.  But Lewis doesn’t actually provide a single argument (at least in his trilemma apologetic) for why Jesus should not, in fact, be considered to have been mentally ill. Looking at the behavior of several biblical characters, including Jesus (see here, too), it’s not actually hard to believe that he suffered from schizophrenia or some similar illness. And of course there was almost exactly zero understanding of the causes of schizophrenia in Jesus’ day, and certainly no treatment. Would it be surprising to see the delusions of some schizophrenics being taken seriously? Probably not.

It should be noted that the arrangement of my flow chart is not unique. The mental illness question could feasibly appear much earlier in the sequence, leading to greater probabilities being assigned to it. Once again, take the entire thing with a pinch of salt.

And maybe make your own, too?


8 Responses to Lewis’s trilemma

  1. L.Long says:

    Of course Lewis is assuming that there was a jesus that said the stuff they say he said.

  2. Excuse me for the simplistic thought that came to me as I read through your posting.

    “For the message of the cross is foolishness to those who are perishing, but to us who are saved it is the power of God. For it is written: ‘I will destroy the wisdom of the wise, and bring to nothing the understanding of the prudent.’

    There are more on worldly wisdom and what it gleans one:


  3. Keith says:


    I understand if you don’t want to tackle Lewis’s trilemma directly. It is unsalvageable after all.

    Better to call me a blind fool instead – it makes you look superior, and it avoids the subject.

  4. Rodney says:

    That’s good – the only problem with it is that it accepts one unwarranted assumption that Lewis (and everyone else who uses this argument makes): that all of the options are at least possible.

    I notice that you allocate the probablility of Jesus being ‘Lord’ as 0.01. Seriously? This option assumes that Jesus was God, which means that he was human and divine at the same time. How is that possible? The attributes of God and humans are mutually exclusive: one is omnipresent, omniscient, omnipotent; the other is limited in space, knowledge and power. No Christian has ever explained how this could work and even Lewis admitted he had no explanation. With faith, you can believe it possible; but otherwise it’s logically impossible – unlike any of the other options. Surely the correct probability is 0. The Lewis argument, in other words, involves getting his audience to reject any number of possible scenarios in favour of the only one that is impossible: a clever piece of flim-flam.

    In fact, what he is trying to do is to prove that Jesus was God and Man, by showing that all other possibilities are not possible. But of course, excluding the others doesn’t make the impossible one possible. The argument only works if a man can be God; but since that’s exactly the point he’s trying to prove in the first place he can’t use it as a logical option. It’s a classic circular argument.

    Here’s another little problem to think over: if Jesus was God, did he know he was? What do you think Lewis thought?

    • Keith says:


      Thanks for the comment. I agree that a probability of 0.01 for the “Lord” option is extremely generous. As you point out, there are additional problems with this option that aren’t addressed in my flow chart, and which could be fatal.

      Regarding your last question, I don’t see any reason (knowing the little of Lewis’s writings and general approach that I do) why he would reject the fairly clear biblical implication that Jesus knew he was God.

  5. Rodney says:

    Well, I would say that any probability other than zero is extremely generous, because it means accepting the assumption that it’s just another option when it’s actually a category error – a completely different way of thinking. The trick of the trilemma is to pull the wool over they eyes of the reader, and making them think that what is actually a completely irrational theological concept is just another option to be considered.

    The reason this completely destroys the argument is not just that it involves accepting an irrational idea, but when you examine the details of the concept the trilemma makes even less sense. What ‘Jesus is the Son of God’ actually means in classic Christian theology is that he was God and Man at the same time – but in that case which kind of consciousness did he have? God’s or Man’s? This is a vital point, since the whole argument requires you to make an assumption about what Jesus believed about himself, and this obviously depends on what he knew. Did he know what God knew, or only what a man would know, or some unexplained combination of both?

    Traditionally, when this argument was first used, Christians assumed Jesus was omniscient, which meant that if he claimed to be God he knew what he was talking about. But by Lewis’ day, theologians had concluded that actually he wasn’t – a point Lewis himself accepted. Clearly, the trilemma makes no sense at all if you admit that Jesus was not omniscient and therefore didn’t know for certain he was God, since the ‘lunatic’ option is no longer available. (And hinting at this without being sure of it is highly irresponsible) Lewis is actually very coy about what he thinks Jesus was actually claiming, though he implies that Jesus knew he was God. Yet elsewhere he writes that Jesus was not only ignorant of some important things but was actually wrong about them.

    The more you examine this argument, the more you discover that Lewis’s thinking was amazingly fuzzy and incoherent – very far from the logical wonder happily cited by apologists.

  6. godbothering says:

    One more option for you: Joker.

    Seriously, I had a friend when I was younger who used to claim to be God. He wasn’t, of course – although to follow Lewis’ logic apparently he was. He certainly was not insane – I would say he was one of the sanest people I have ever known. And he was not lying – we all knew he wasn’t God and he wasn’t attempting to deceive us. He said it in such a deadpan way that if you didn’t know him you might think he was serious. But of course it was a joke – just one that derived its main impact from the fact that he said it with such confidence and seriousness.

    Now, I know it’s unlikely that Jesus was a sort of first-century Bozo the Clown but one of the highly characteristic things about his language was the provocative, sometimes extreme, way he spoke. Does anyone believe he really intended that his followers, if they were offended by something they saw, to tear their eyes out? Of course not, he just spoke that way as a figure of speak to get them to think. One important trend of recent New Testament scholarship sees Jesus as a kind of ‘wisecracking sage’ of the Greek cynic tradition (it’s not all that convincing but it is taken quite seriously). All of this means that it’s entirely possible that the statements made by Jesus (not that he ever really claimed to be God or anything like it) could have been intended, and understood by those who heard it, merely to provoke a response.

    I think you should add this into your diagram (which, by the way, is an excellent idea and I like it a lot).

    Sorry for ranting on again. I’ll stop now …

    • Keith says:

      That is an excellent suggestion.

      It’s a distinct, and perfectly valid category. I’ll add it as soon as I can find my original files 🙂

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