The Mindless Hypothesis

In the previous post, I talked about Alex Byrne’s paper Skepticism about the Internal World (PDF). In that post, I focused on the first part of the paper, and in this post I’ll focus on the second (and main) part of the paper.

Byrne’s Outline

In the first part of the paper, Byrne argues that skeptical arguments about the external world are not very convincing. In the second part, he says that there are parallel arguments about the internal world that are more convincing. He concludes that we can have more confidence in the external world than in the internal world.

In the previous post, I tried to show that there are serious objections to his claims about external world skepticism. In this post, I’ll try to show that his claims about internal world skepticism are based on some mistaken assumptions.

The Sleeping Cat

Byrne asks to consider the following scenario:

“Suppose you are facing a cat asleep on a mat, the light is good, your visual system is working perfectly, and so on. Then, by using your eyes, you can come to know that the cat is asleep on the mat (or so we think). What you know—that the cat is asleep on the mat—has nothing to do with you or your perceptual state. The cat would have been peacefully sleeping whether or not you had been around to notice that fact.”

Now, there is some evidence about this scenario — that the cat is black and furry, is on a mat, is in the sunlight, that you are facing it a few feet away, etc. Let’s call this evidence E. What Byrne wants to say is that there are two hypotheses compatible with this evidence.

The Seeing Hypothesis

The first hypothesis is the intuitive one — namely, that I am seeing the cat. According to this hypothesis, I have a mind, and my mind is having a visual experience of seeing the cat and the mat and the sunlight and so on, and is coming to conclusions such as that the cat is asleep.

But Byrne suggests there is a second hypothesis that is just as compatible with the evidence.

The Mindless Hypothesis

Here is Byrne’s description of the second hypothesis:

“For maximum vividness and generality we can make the alternative hypothesis as radical as can be. Consider the hypothesis that you do not have a mind at all. Outwardly you look and behave just as a minded person does, but really all is dark within: you do not see anything, think or believe or want or feel anything, and so on. So, in particular, you do not see the cat, despite its being (say) a few feet away in front of you in broad daylight. Call this the mindless hypothesis.”

This does indeed seem radical, but not only does Byrne think it is compatible with the evidence but that “Offhand, it is not clear at all why this evidence favors the seeing hypothesis over the mindless hypothesis.”

You might think that this is simply incoherent, because it obviously seems to you (in this scenario) that you see a cat. But Byrne anticipates this objection:

“According to the mindless hypothesis, it does not seem to you that you see a cat, for exactly the reason given in the objection. If the mindless hypothesis is right, you do not perceive, believe, or desire, and neither does it seem to you that you see, believe, or desire.”

The Formal Argument

Given the evidence E, and the two hypotheses just discussed, Byrne makes a formal argument that is similar in structure to the external world arguments that we discussed last time.

P1*. If you know that the seeing hypothesis is true, you know this solely on the basis of your evidence about your environment.

P2*. This evidence does not favor the seeing hypothesis over the mindless hypothesis, and so does not allow you to know that the seeing hypothesis is true.

C*. You do not know that the seeing hypothesis is true; that is, you do not know that you see a cat.

Medium vs. Message

How could the second premise P2* possibly be true? In other words, how could the evidence of the cat being black and furry and lying in the sunlight be compatible with me being wholly mindless? To give Byrne’s answer to that, we need to back up a bit to an earlier point of the paper.

Consider reading a newspaper, and that you’re reading a sports story about a baseball game. If prompted, you could answer questions about what happened in the game — perhaps the Red Sox came from behind to beat the Yankees, for example. And if prompted, you could also answer questions about the medium, such as whether the story is printed in multiple columns, or what kind of paper it’s printed on. There is the medium and there is the message, and they are clearly distinct, and you could alternate between focusing on one and focusing on the other.

Byrne’s key point is that visual experience is not like this. If I ask you “Is there a cat on the mat?” you can attend to the evidence in the environment and give an answer. And if I ask you a question about your experience such as “Do you see a cat on the mat?”, you will attend to the same evidence and give an answer. Your processes in answering the two questions do not seem so different. The seeing is invisible, Byrne argues. There is no medium vs. message distinction of the visual experience, in his view.

So what we immediately attend to is the evidence, even when we are asked about our visual experience. And so the evidence seems to be separate from our visual experience. The evidence is not conveyed by our visual experience in the same way that the baseball game information is conveyed by ink on paper. The evidence is somehow separate from our experience, and in fact we begin with the evidence in order to attend to our visual experience. That is how Byrne sees P2* as being true.

Where Byrne Goes Wrong

The denial of that medium/message distinction is where Byrne goes wrong, I think. There is a medium vs. message distinction in the visual experience. Let me make three objections.

Objection 1: Most people will interpret “Do you see a cat on the mat?” as essentially equivalent to the question “Is there a cat on the mat?” That is, they do not see the first question as explicitly about the visual experience, unless it were contrasted with a different sense modality or somehow placed in a context that emphasized the visual experience. So it’s not surprising that a person would go through the same basic process in answering both questions.

Objection 2: A seeing experience always involves something being seen, so it’s difficult to talk about a visual experience without mentioning what is seen. But that doesn’t mean the things being seen somehow come prior to the experience.

Objection 3: We can fairly easily think of examples that contrast the medium and the message of the visual experience. For example, I could say “I am currently experiencing tunnel vision, but yes, I see a cat.” Or consider someone who has blindsight in one half of their field of vision. Some of the evidence is in the half with blindsight and some of the evidence is in the half with normal vision. They can reliably answer questions about the evidence in both halves (or answer at better than chance levels, at least, and perhaps answer reliably in the hypothetical case of superblindsight), and they can also give reports contrasting the visual experience they are having in one half with the lack of visual experience they are having in the other half. So they can attend to the message (answering questions about the evidence in both parts of their visual field) or they can attend to the medium (reporting that they have visual experience in one half but not the other).


So I think Byrne is wrong to say that there is no medium vs. message in the visual experience. And if he is wrong about that, then P2* is false. The evidence is not somehow separate from or prior to my experience, and so the evidence is not compatible with me being mindless. Since P2* is false, the conclusion is avoided.

I enjoyed the paper. It is very well-written and accessible, which is not always the case with academic philosophy papers. It is also very subtle. Figuring out where the argument goes wrong was a challenge, but I do hope that I showed it is wrong.

Other Afterthoughts

Byrne doesn’t actually believe the mindless hypothesis is true. He just says it can’t be ruled out, and as such it shows that it is very mysterious how we have knowledge of our internal worlds. I am saying that it can be ruled out. The evidence is not compatible with me being mindless.

When I made an allusion to the mindless hypothesis on Twitter, several people thought I was talking about illusionism, the view that we lack phenomenal consciousness (or qualia):

But the mindless hypothesis is more extreme than the illusionism about phenomenal consciousness proposed by people like Keith Frankish. Keith believes that we have minds, and that we have other forms of consciousness like access consciousness, and that we have dispositions to judge that we have phenomenal consciousness. In contrast, the mindless hypothesis says that we have none of that whatsoever.

I believe illusionism is wrong. But showing it is wrong is more of a challenge. The mindless hypothesis, though, can be ruled out.

This Post Has One Comment

  1. Ilyass

    Just because we can’t prove Illusionism doesn’t mean it’s true or strong, actually all metaphysics are improvable.

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