How to answer the Sye-clone: Wittgenstein’s transcendental argument

0. Introduction

In a previous post, I have talked about transcendental arguments as used in philosophy. I briefly mentioned one such argument found in an aphoristic comment in Wittgenstein’s book, On Certainty. In this post, I am going explain a plausible argument which can be extracted from Wittgenstein’s aphorism. Specifically, I will say how this works as a sort of strategy for dealing with various radically sceptical challenges that could be posed to you; i.e. for dealing with the types of ‘Sye-Ten Bruggencate challenge’.

  1. Wittgenstein’s Aphorism

On Certainty is the last book that Wittgenstein composed. Really, it is jut the collected papers that he was working on in the final months of his life, which were published posthumously. Here is the quote that I want to focus on:

“383. The argument “I may be dreaming” is senseless for this reason: if I am dreaming, this remark is being dreamed as well – and indeed it is also being dreamed that these words have any meaning.” Wittgenstein, On Certainty.

I want to say that there are two distinct arguments in this passage, which I will call the argument from obligation, and the argument from meaning respectively. I will look at the argument from obligation here, and cover the argument from meaning in a subsequent post.

2. The argument from obligation

The key idea behind the argument from obligation is that in a dream one cannot be under any types of obligation.

Imagine a person, Scrooge let’s call him, who is miserly and mean throughout the day, every day. Each time he gets the chance to be mean to someone, he takes it. However, when Scrooge goes to sleep at night, he always has the same dream, in which he is a kind and generous man. In his dreams, whenever Scrooge gets the chance to be nice to someone, he takes it. If we come to make a moral evaluation of Scrooge, I think that we would have to say that he was an entirely miserly and mean individual. His dream-world generosity does not count at all in favour of him being a good person. Dream actions have no moral value whatsoever.

It follows from this that if one is having a dream, then one is not under any moral obligations with regards to the things in the dream. Imagine you have a dream in which you do something morally wrong, like stealing. Upon waking, although you may still feel guilty about what you did in your dream, you have not actually broken any moral obligations, because you didn’t actually do anything, let alone anything wrong. It was only the illusion of doing a morally wrong action.

To press the point, if I dream that I murder someone in cold blood, I do not need to fear going to prison when I wake up, because I have done nothing wrong. Likewise, if I am playing a one-player computer game, like GTA5, and I decide to randomly kill a passer by in the street (we’ve all been there), I have not actually violated any moral proscription against murder. Dreams, like computer games, are not real contexts as such. They are illusory contexts, ones in which moral choices are not evaluated at all. We might say that they are amoral contexts.

The reason these contexts are amoral is that there are no actual agents playing the roles of the injured parties. The utilitarian does not count as harm violent deeds done to a computer sprite, nor to a character in a dream. A deontologist does not include proscriptions about computer sprites or characters in dreams. Each of these two major meta-ethical schools concerns themselves with real agents, not characters in dreams.

What holds for moral obligation, also holds for rational obligation. Imagine someone, let’s call him Scrooge again, who spends all his time constantly debating people in chat rooms online, but constantly failing to live up to his rational obligations. So, he does things like making arguments that have their conclusions explicitly stated as one of the premises. He makes assertions, such as that p is true, but when asked to justify the claim, passes the burden to his interlocutor to prove that p is false, or he provides a deductively invalid or unsound argument, etc. Whenever he has the chance to duck a rational obligation, he takes it. However, every night Scrooge has the same dream where he is constantly debating people online, but now he is the model rational agent and always abides by the rules of rational discourse. Whenever he makes a claim, he backs it up with either a plausible looking deductively valid argument, or he provides some compelling piece of evidence, etc. However, if we come to assess Scrooge’s behaviour in terms of his rationality, we would have to say that he is actually a very irrational interlocutor. All of his actual interactions have him constantly ducking his rational obligations. Just as in the moral case, the fact that he is very well behaved in his dreams doesn’t count for anything.

So, just as dreams are contexts in which there are no moral obligations (amoral contexts), they are also contexts in which there are no rational obligations (arational contexts).

If this preceding line of argument is correct, then we have an interesting result when faced with a radical sceptical doubt, such as the doubt that one is dreaming. The insight comes out if this sceptical challenge is posed as an explicit question, in the form “how do you know you are not dreaming?”

Here it seems that there are really two options: either you are dreaming, or you are not. As we have seen from the above considerations, part of the difference between being awake and dreaming has to do with the presence of obligations, both moral and rational. So when the question is posed, there are two possibilities – either you are dreaming or you are not – and these correspond to either being under obligations (moral and rational) or not. When dreaming, you are not under any obligations. So, if, during a philosophical conversation, the sceptic asks you to to show that you are not dreaming, then on the assumption that you are in fact dreaming, you are not under any rational obligation to provide any kind of answer. It doesn’t matter if offer an invalid argument as your rebuttal, or just walk away and make a sandwich. You are not really having a philosophical conversation at all, and are not really under any rational obligation to justify your claims, or argue consistently, etc. In a dream context, these obligations are just not present. So, if you are dreaming, you do not have to worry about answering the sceptical question.

If you are not dreaming, then you are under all moral and rational obligations. But that means that you need to provide justifications for your positions on things to remain rational, only if you are not dreaming. Thus, being awake is a necessary condition of being under the rational obligation to respond to a potential sceptical challenge.

Here is the argument in premise-conclusion form:

  1. For all rationally obligatory actions x, one is obliged to do x if, and only if, one is awake (i.e. not dreaming).
  2. Answering the sceptic’s question “how do you know you are not dreaming?” is a rational obligation.
  3. Therefore, one is obliged to answer the question “how do you know you are not dreaming?” if, and only if, one is awake (i.e. not dreaming).

It has the form, where O(x) means ‘x is rationally obligatory’, p means ‘you are awake’, and a is ‘answering the sceptic’:

  1. ∀(x), O(x) iff p
  2. O(a)
  3. Therefore, O(a) iff p     (∀-instantiation)

3. Conclusion

What the argument from obligation argument shows is that one is not under the rational obligation to answer a sceptic who wants you to justify that you are not dreaming. If you are dreaming, then you are not under any actual challenge to defend yourself against, on pain of being irrational. In fact, nobody has challenged you at all; there is no sceptic, there is no challenge. The whole context is illusory. On the other hand, if you are in fact under the obligation to make some kind of rational response to the challenge, this must be because you are really in a conversation with someone, and not dreaming the exchange. Thus, being awake is a necessary precondition for the intelligibility of the sceptical challenge itself. We must presuppose that we are awake for the question to be something we are rationally obliged to respond to.

Skepticism, fallibilism, anti-skepticism

    0. Introduction

The following three propositions form an inconsistent triad:

P)   I do not know that I’m not in the matrix*

Q)   I know that X

R)   If I know that X, then I know that I am not in the matrix


(X is to be thought of as a proposition with content about the external world, such as ‘it is 3PM’ or ‘I am wearing trousers’, etc, rather than ‘I believe it is 3PM’ or ‘I am receiving sense-data about wearing trousers’, whose content is internal to the subject.)

We can represent the logical form of the propositions as follows, where p = ‘I know I am not in the matrix’, and q = ‘I know that X’:

P)    ~p

Q)     q

R)     q → p

There are three ways that we can formulate an argument using these propositions which generate three positions about knowledge, which I am calling ‘skepticism’, ‘falliblism’ and ‘anti-skepticism’. Each argument is derived by having two of the propositions as premises with the negation of the remaining one as the conclusion.


  1. Skepticism

The skeptic formulates her argument as follows:

R)     If I know that X, then I know that I am not in the matrix

P)     I do not know that I am not in the matrix

~Q)     Therefore, I do not know that X

This argument has the form of modus tollens:

q → p


Therefore ~q


2. Fallibilism

In contrast, the fallibilist argues from the truth of P and Q to the falsity of R, i.e.:

P)      I do not know that I am not in the matrix

Q)      I do know X

~R)     Not-(if I know that X, then I know that I am not in the matrix)


This has the form:



Therefore, ~(q → p)


What does this rearrangement say? It says that because we do know something, yet we do not know whether we are in the matrix, it follows that knowing that we are not in the matrix it is not a necessary condition for knowledge. Thus one can have knowledge without being able to rule out the skeptical hypothesis.


3. Anti-Skepticism

The final combination, the anti-fallibilist (which perhaps represents G.E. Moore?), runs as follows:R)   If I know that X, then I know that I am not in the matrix

Q)   I know that X

~P)   I know that I’m not in the matrix


The form of this argument is modus ponens:

q → p


Therefore, p


On this argument, the requirement of ruling out the matrix as a necessary condition for knowledge is accepted, and the fact of knowledge of X is affirmed, with the consequence that one knows they are not in the matrix. A refutation of the skeptical hypothesis has been achieved (hence the name ‘anti-skepticism’).



4. How to choose? 

So now we have three rival arguments, each of which picks two of the members of the triad and rejects the third. The question of which argument to pick turns then, not on logic as such, but on the question of which proposition to jettison. Which one seems the least plausible? The problem is that they all seem eminently plausible.

P says that you cannot rule out the matrix, or evil daemon hypothesis. It seems very plausible, at least to anyone who has read Descartes or watched the Matrix. Denying this premise seems to require a refutation of skepticism.

Q says that you know that X. This is obviously going to depend on your choice of X, but why not make X as plausible as you like? Let X be ‘it is now 3PM’ (if it is 3PM), or that you are wearing trousers (if you are wearing trousers), etc. It can be the most run of the mill, ordinary knowledge claim you can think of. By definition, Q should be very plausible, if any knowledge claim at all can be. And P, Q and R are all knowledge claims.

R says that if you know that you are walking down the street, or that it is 3PM, or that you are wearing trousers, or whatever, then you know you are not in the matrix. This is also very difficult to deny. If I know that I am walking down the street, then it is true that I am walking down the street. If it is true that I am walking down the street, then I am not in the matrix. Thus, if I know I am walking down the street then I am not in the matrix. Therefore, it seems that if I know that X, then I know I am not in the matrix.

Where is the weak link here?


*for ‘in the matrix’, feel free to substitute in ‘am a brain in a vat’, ‘am being deceived by a Cartesian daemon’, etc.