Heather Logue is a Lecturer in Philosophy at the University of Leeds. Her research focuses on issues in metaphysics and epistemology, and particularly on issues concerning perceptual experience. She has published and forthcoming papers on Naïve Realism, disjunctivism, skepticism about the external world, and the metaphysics of color; and she co-edited (with Alex Byrne) Disjunctivism: Contemporary Readings (MIT Press, 2009). Before coming to Leeds, Heather completed her PhD at MIT in 2009 and her bachelor’s degree at the University of Pittsburgh in 2003.

How You Know You’re Not in the Matrix

Heather Logue

As it happens, the movie “The Matrix” came out just as I was taking my very first philosophy class, and as I was reading Descartes’ Meditations for the first time. I was gripped by the problem of explaining how we know we’re not being deceived by evil demons and machines. I eventually became interested in the philosophy of perception because I had a hunch that the metaphysics of perceptual experience might hold the key to the most satisfying response to arguments for skepticism about the external world. In what follows, I summarize my most recent attempt to make good on this hunch. It comes from my paper “World in Mind: Extending Phenomenal Character and Resisting Skepticism”, which is slated to appear in a volume on experiential reasons, and is based on a presentation that I gave to a general audience in Edinburgh last year. In case you’re interested, it’s available online here:

In “The Matrix”, humans are used as batteries by their robot overlords. They are blissfully unaware of their subjugation thanks to the Matrix—a machine that stimulates their brains so that they’re having perceptual experiences that they couldn’t tell apart from ordinary ones. By ‘ordinary experiences’, I mean ones generated through normal interactions with the world beyond the Matrix. And by ‘Matrix experiences’, I mean the ones that philosophers call total hallucinations—experiences that merely seem to be of the world, when in actual fact you’re not perceiving anything in you’re environment at all. It seems to the people plugged into the Matrix that they are taking walks through parks, enjoying delicious ice cream, stubbing their toes on bedposts (and so on), when all the while they are just stuck in vats of goo.

This imagined scenario is troubling: if the characters in the movie can’t tell whether they’re in the Matrix, how can we? On the face of it, what it would be like to be in the Matrix is exactly the same as what’s it’s like to interact with the ordinary world. Hence, we can’t tell our experiences apart from Matrix ones, and we can’t know that we’re not in the Matrix.

I think that this is a genuine worry only given two assumptions (which, it must be said, are held by most philosophers). In the rest of this post, I will explain the assumptions, how one can reject them, and how rejecting them could give us knowledge that we’re not in the Matrix.

The first assumption is that what it’s like to have an experience (its phenomenal character) is entirely “in our heads”. As I think of it, the phenomenal character of an experience is (roughly) its “feel”—it feels different to experience red than it does to be tickled, or to experience green. This assumption says that the feel of an experience is entirely down to what’s going on inside our heads (presumably, our brains).

The second assumption is that we can have knowledge of our experiences in the Matrix. The idea is that all we have to do to know things about our experiences is to (in some sense) look within. By looking within, I can at least be certain that I’m having an experience of a yellow thing, and that my experience has the feel associated with experiences of yellow things. Even the poor humans stuck in the Matrix can do this—they can look within, even if they can’t look without. So even though they can’t know anything about what’s going on around them, they can at least have knowledge about their experiences.

Contrary to conventional philosophical wisdom, I think we should reject these two assumptions. And if we do, we have a way of knowing that we’re not in the Matrix.

As for the first assumption, I think we should reject the claim that phenomenal character is entirely in our heads, and hold that it includes things outside it. In particular, we should say that what it is like to have an experience consists in perceiving things in one’s environment. (This kind of claim is a version of what’s commonly known as ‘Naïve Realism’, or the ‘Relational View’ of perceptual experience.) For example, on this view, what it is like to experience yellowness consists in perceiving an instance of yellowness. It would take me too far afield to explain why I am attracted this view here (but if you’re interested, you can check out my paper “Why Naïve Realism”). For present purposes, the pressing issue is why most philosophers don’t hold it.

Most would balk at what it entails about total hallucinations. Since total hallucinations don’t involve perceiving things in one’s environment, this view entails that there’s nothing it’s like to have them. Surely that’s absurd! Someone having a total hallucination can’t tell it apart from an ordinary experience. Surely that entails that what it’s like to have them must be exactly the same, and so that there must be something it’s like to have a total hallucination (since there is something it’s like to have an ordinary experience).

Or does it? This is where the rejection of the second assumption comes in—that we can have knowledge about our experiences in the Matrix. Let’s think more carefully about how we get knowledge of our experiences. Do we really learn about them by looking within? It seems to me that we actually learn about them by looking without—by attending to the things in our environments that we perceive. (This model of how we acquire knowledge about our experiences is inspired by the one outlined in Evans 1982: 227-8.) For example, if you ask me what I’m experiencing right now, I don’t know what to do in order to answer your question other than to look out to what’s going on in my environment, and report back: I’m experiencing something yellow.

Notice that this way of getting knowledge about our experiences couldn’t work properly in the Matrix. The subjects of Matrix experiences don’t perceive anything in their environments. So when they try to attend to what’s going on in their environments, it turns out that they can’t. Given that they can’t do what they’re supposed to do to get knowledge of their experiences, it wouldn’t be surprising if they ended up with a bunch of false beliefs about them. One such false belief could be that there’s something it’s like to have their Matrix experiences. That is, they would form the belief that there’s something it’s like for them to have their experiences, even though this belief is false—because their way of getting knowledge about their experiences can’t work properly in the Matrix.

In short, if we deny the second assumption, it’s not absurd to deny the first. The denial of the first assumption was that the phenomenal character of an experience partially consists in things outside the head. The reason this seemed absurd was that since total hallucinations can’t be told apart from ordinary ones, it must be that what it’s like to have them is the same. This means that total hallucinations have phenomenal character, which must be entirely a matter of brain stimulation. But if we deny the second assumption in the way I suggested, we can admit that total hallucinations can’t be told apart from ordinary ones, but insist that this is not because what it’s like to have them is the same. Rather, it’s because our way of knowing about them doesn’t work properly in the Matrix. (For more details, see my paper “What Should the Naïve Realist Say about Total Hallucinations?”)

Finally, if we deny the first assumption, we can know that we’re not in the Matrix. We can know we’re having ordinary experiences rather than total hallucinations by knowing that there’s something it’s like to have them. After all, on my view, only ordinary experiences have a feel to them. So we can know that we’re not having Matrix experiences by knowing that we’re having experiences that have a feel.

I realise that this isn’t going to initially strike most readers as satisfying. For given that we would falsely believe that there is something it’s like to have our experiences if we were in the Matrix, how can we rule out the possibility that the experiences we’re having right now are Matrix experiences? It seems to me that this question expresses a demand for the impossible: a way to “step outside” our experiences in order to compare them with the external world, in order to check whether they “match”. But, much as we might like to, limited creatures like us cannot take an experience-independent perspective on the external world. As far as I can see, that’s the only way we could go about ensuring that we wouldn’t believe that we weren’t in the Matrix if we in fact were. But since it simply isn’t available to us, I think we ought to reject the idea that knowing that p requires that one wouldn’t believe that p if it were false (i.e., that sensitivity is a necessary condition for knowledge).

This broad kind of strategy isn’t novel (see, e.g., Sosa 2000, Williamson 2000, and Pritchard 2012, among others). But I have found previous implementations of it unsatisfying. They are short on detail when it comes to the following question: what exactly is it about perceptual experience that puts us in a position to know that we’re not in the Matrix? I have suggested that its phenomenal character plays this epistemological role. Sure, we would falsely believe that our experiences had phenomenal character in cases of total hallucination. But (as even Descartes conceded in Meditation I) the fact that a mode of epistemic access yields false beliefs in conditions unfavourable for its employment does not impugn its capacity to yield knowledge in favourable conditions. So the fact that total hallucination is a defective context for getting knowledge about experiences (as I suggested above) doesn’t mean that it cannot afford knowledge that our experiences have phenomenal character—and thereby, the knowledge that we’re not in the Matrix—in ordinary circumstances.

References

Evans, G. 1982. The Varieties of Reference. Oxford: Oxford University Press.

Logue, H. 2012a. What should the Naive Realist say about total hallucinations? Philosophical Perspectives 26: 173-99.

Logue, H. 2012b. Why Naive Realism? Proceedings of the Aristotelian Society 112: 211-37.

Pritchard, D. 2012. Epistemological Disjunctivism. Oxford: Oxford University Press.

Sosa, E. 1999. How to defeat opposition to Moore. Philosophical Perspectives 13: 141-54.

Williamson, T. 2000. Knowledge and Its Limits. Oxford: Oxford University Press.