The New York Review of Ideas » Q&A | June 2009
Out of Our Minds
UC Berkeley’s Alva Noe argues that there is more to perception than the brain.
By Margaret Wheeler Johnson
In his first book Action in Perception (The MIT Press, 2004), Alva Noe, professor of philosophy at the University of California Berkeley, proposed that we perceive the world with our whole bodies, not just our optical faculties.
Recently the New York Review of Ideas spoke with him about his latest book, Out of Our Heads: Why You Are Not Your Brain and Other Lessons From The Biology of Consciousness (Hill and Wang / Farrar, Straus and Giroux, February 2009). In it he argues that the mechanisms of consciousness lie not within the brain but in the interaction between the nervous system and the external world.
Your central claim in Out of Our Heads is that we are not just “minds in vats.” What do you mean by that?
It’s an idea that dates at least from the period of the early scientific revolution. Descartes felt that there is in each of us a thinking thing—he called it a cogito—that feels, that decides, and that each of us is this kernel of consciousness inside.
Surprisingly a certain dominant perspective in neuroscience simply accepts that Cartesian picture whole hock, with one little exception: they think that the thing inside of us which we are is the brain.
What I’m suggesting is that the best way we can understand the brain’s contribution to conscious life is by realizing that the brain is one element in a more complex dynamic between the whole animal and its environment.
But isn’t it the brain that takes in stimuli from the outside world and produces conscious awareness?
I sometimes compare consciousness with dance. I think of ourselves as perceptually engaged with the world around us, and thinking that you can explain it just in terms of what’s going on inside of us is like thinking you could explain dance just in terms what’s going on in our muscles. What I want to say is that it’s true that the world acts on us through the brain, but the brain acts on us through the world. If you remove the world—and the way in which we’re already smack dab in the middle of engaged living with other people—I don’t think you describe any interesting mental phenomena in neurological terms alone.
The proposal I’m making is that it’s not the brain alone that matters; it’s the brain as coupled to the rest of the world, thanks to the whole body. Trying to find consciousness in the brain is like trying to find the monetary value of the U.S. dollar in the composition of the dollar bill—as if I was going to run a dollar bill through an electron microscope and learn something about what it was worth. That’s just the wrong place to look. Not that dollar bills don’t play a role in the economy. They do. Actually, here the analogy breaks down because I think the stuff that goes on in the brain is, in fact, causally involved in our experience of the world in an important way. But not all on its own.
Who disagrees with you?
Mainstream cognitive science supposes that the problem the scientist faces is understanding how the brain builds up a representation of the world around it on the basis of the array of information bombarding the nervous system of the animal. And then they try to come up with models about the way in which the brain does all that work—computational models of the way it might work. There’s really very few people who break with that.
Does experimental research support their position?
The interesting thing is that in practice science does take for granted the embodied situated life of the animal. When you’re doing experiments on an animal, you’re always doing experiments on an animal with a body. But usually they anesthetize an animal, rigidly pin it so that it can’t move, and present stimuli to it while they insert electrodes into the head of the animal. That method rules out the possibility that active engagement or free movement or the alert interest and motivation of the animal play any role in even the operation of its own nervous system. All of that is just bracketed and left out. The brain is studied just as a kind of reactive device triggered by numerous stimuli. You learn all sorts of interesting stuff about the brain that way, but the question is, how does what you learn about the brain relate to the rest of our lives?
Are you saying there is no way to anatomize consciousness, to say that this series of synapses gives rise to this kind of thought or impression?
Everybody in the field agrees that at the moment we don’t have even a back-of-the-envelope sketch of a theory of how what is going on in the brain explains any fundamental features of consciousness. It’s very probably the case that, given our involvement with the world around us, there are meaningful patterns in how what is going on in our brains corresponds to what is going on in our mental lives, but that’s because we already have the background of the living animal’s engagement with the world in place to frame the kinds of things we’re looking for in the brain.
I take great interest in the phenomenon of neuroplasticity. If you surgically alter an animal like a ferret at birth, you can cause retinal cells to sprout projections into the parts of the brain that normally would have supported hearing, and these ferrets can negotiate the world visually. They can see using a different part of the brain as the visual cortex. That’s one of the things that tells me that relationships of states of consciousness to states of the brain are not one-to-one. It’s not as though there’s something about the intrinsic character of v-cells that makes them visual cells. In fact, I think it’s because of this plasticity that many different physical states can give rise to the same kind of experience, and different kinds of mental experiences can arise out of the same kinds of physical states and relationships.
People talk about the explanatory gap. If we want to understand why this kind of experience is produced by this kind of pattern of select activity in the brain, we need to ask what’s the third term that’s linking those two things together. My empirical proposal—and it is empirical—is that the best way to understand those selections is by referring to the animal’s behavioral and environmental context.
So would you say that consciousness is a biological phenomenon?
What I’m trying to make problematic is what it is to offer a biological explanation of these things. What is our biology? If I’m right that the brain’s function is so coupled to a larger context of environment, then biology needs to be pitched at this higher level.
I want to shift the paradigm regarding what the biological is. In Out of Our Heads I talk about the way in which habits and background all change the problems we think biology needs to explain. I’m struck by how un-biologically some neuroscientists think of the brain—as a computer, a Cartesian soul, not part of our biology. There is something not only false but also ugly about the conception of ourselves that people have who think that we are our brains. My view is not that the problem with the neuroscience is science. It’s science that’s straight-jacketed by some bad philosophy.
What are you working on now?
I’ve been thinking a lot about the human being as a technological species. It seems to be a basic fact about the way we cope with living that we use tools in certain kinds of ways. We make clothing, we make shelters, we create environments for ourselves. And there’s a sense that the dwellings that we build and the clothing that we wear and the implements that we manufacture are as much a part of our biology as say the hives of the wasps or the nests of the birds is a part of their biology. That is, technology is a part of biology. Once you recognize that, it really changes how you think about biology.♦