Brain Views

Brain Views

Oh, those perishing bats, hogging all the limelight, with their fancy sense of echolocation! Let’s talk about the humble human and how things look to him or her. Can this be reduced to brain states? We have agreed that consciousness is having a point of view, specifically a visual one; can we argue that this point of view cannot be merely physical? Can we formulate an anti-physicalist argument based around the notion of a visual point of view? And is this helpful? Yes, we can, and yes, I think it’s a helpful to do so. The argument is very intuitive when framed this way. Suppose you are sitting across from me, with a different visual perspective; and suppose I can see your brain, specifically what is happening in your visual cortex. I see the physical correlate of your visual experience, but I don’t see your visual experience—I have to imagine that. I don’t use my imagination to know about your brain state, but I have to use it to know about your conscious state. So, how can the two things be identical? I might find it difficult to fire up my imagination in order to obtain this knowledge—it takes some effort. If I am very unimaginative, I might fail. But I don’t need to make any effort in order to know what is happening in your brain—I can just look and see (it might be recorded up on a screen or actually open to view). My view of your brain is unimpeded, but I have no view of your view, only an act of imagination. The brain is in its nature something open to visual inspection, but your visual experience is not; it is not perceptible at all, being (as we say) private. You can’t view a view.

This is a mild example of epistemic difficulty; most people have no trouble imagining the other person’s perspective (but do they know it as well as the person who has that perspective?). Imagination can provide knowledge of other minds. But notoriously, it will only take you so far: can a person with impaired vision imagine the vision of someone visually unimpaired, or a color-blind person imagine the vision of someone not color-blind, or a bat imagine the vision of an eagle, or a human imagine the vision of a fly, or a human imagine the vision of a visually superior alien, or even of a bee? Imagination is a frail reed when it comes to knowing the nature of visual experience in general—and why should be it be omniscient in this respect? But this limitation is irrelevant to knowledge of the brain; here we can just look and see—we can inspect the brain to our heart’s content. It puts up no resistance; it doesn’t run and hide; it is quite open about what is in there. It can be viewed from afar or up close or under a microscope. But visual experience can’t be viewed at all and must be conjectured based on imagination or projection or surmise. The mind is private by nature and the brain is public to a fault (introvert and extravert, respectively). Suppose the difference between my brain and yours is that I have neurons that fire with greater frequency than yours do, or my neurons have longer axons; and suppose this is the physical basis of the difference in the way we see things, say colors. In such a case I have absolutely no difficulty knowing the physical difference between us, but I face an opaque wall when it comes to knowing your visual experiences, supposing these to be very different from mine. Your experience is closed to me but your brain is an open book. And this is part of the essence of experience and the brain: the brain is inherently knowable in a certain way, but the mind is inherently not knowable in that way. To be conscious is to have a point of view, but points of view can’t be viewed, while brains can be. Thus, I can form a conception of your brain by perception, but I can’t do that with your mind; I can’t perceive your perceptions. My consciousness cannot be a consciousness of your consciousness—my point of view can’t take in your point of view as direct object. Views can’t be viewed. Simple as that.

This is really just another way to state the bat argument or the “knowledge argument”. But it is extremely simple and requires no elaborate thought experiments or alien beasts. It requires only the simple idea that points of view can’t be viewed: you can’t look at what someone else is experiencing; you can’t have an experience as of an experience. If you could, there would be no limitation on our knowledge of other minds deriving from differences in how we experience the world. Everyone would know what anyone else is experiencing just by looking at their brain (or face): visible brains (or faces) would produce knowable minds. Indeed, to see a brain would be exactly the same experience as seeing a mind, but it isn’t. There would be no other minds problem, but there is. There would be no ignorance of an alien creature’s experience, but there is. It follows that mind cannot be identified with brain. The root cause is privacy; or rather, mental privacy combined with brain publicity. For if the brain were as private as the mind, there would be no epistemic discrepancy. This is really the thrust of the standard argument, though it may be obscured by standard presentations. Just remember: you can’t view a view, but you can view a non-view (like the physical brain). This is why you can’t know alien experience but you can know alien brains. Brains cause themselves to be seen, but minds don’t cause themselves to be seen. It would not be possible to start with not seeing someone else’s mental state (as such) and then gradually home in on it till you see it in the form of a brain state. Nor would it be possible to start with a seen brain state and gradually alter the viewing conditions until it vanished into a mental state. But you could begin by seeing water in the normal way and gradually magnify it till the H2O molecules became visible, or begin with the molecules and pull back till you saw the watery liquid as you normally see it. You cannot see a mental state as a brain state or a brain state as a mental state.[1]

[1] The problem with the bat is that we can’t see its echolocation experiences; if we could, we would be able to form a conception of them. But then, there would be no argument to the effect that one can be known and the other not known. However, the imperceptibility point immediately shows that mind and brain cannot be identical (short of a convincing rebuttal). That is the underlying mechanics of the argument. Other minds must be imagined, since they cannot be perceived; but brains can always be perceived, so there is no need to imagine them.