The stimulus for today’s post is an article by Raymond Tallis that appeared in The New Atlantis for last Fall. This article takes a stand on many issues of interest to me and that I’ve written about in Your Brain and You. I find myself in fundamental agreement with some of what Tallis says, and also in fundamental disagreement with other points he makes.
Tallis makes far too many points to take up in one post. I’ll confine myself to two. The first is a point of agreement: There is no account that our sciences give of why there should be any appearances of things whatsoever. “Appearances” include the painful way damage to your body feels to you, the way a cup of hot coffee or a glass of iced tea feels to you, the way things look to you (bright or dim, this or that color), the way things taste and smell to you, and so on.
This point may be most easily seen with tastes and smells. Chemistry tells us that there are molecules of various kinds in the foods we eat and in the air near many flowers. Neuroscience tells us that molecules of each kind cause activation in some of our specialized sensory receptor cells, and not in others. Each of these cells stimulates some, but not all, of our neurons that lie deeper in our brains.
The specialized cells and their connections explain how we can react differently to different molecules arriving on our tongues or in our nostrils. But nowhere in the sciences is there an explanation of why or how the firing of our neurons causes orange flavor, chocolate flavor, lilac scent or outhouse odor.
Many contemporary philosophers are content to say that experiencing a flavor or a scent just is the very same thing as having a set of neural firings of a particular kind. This claim, however, does nothing to explain how it is possible for an experienced flavor or scent to be the same thing as a bunch of activities in nerve cells. The best that can be said for such an identity view is that it is simple, and that it cannot be proven to imply a contradiction. That’s a pretty weak reason: Berkeley’s view that there are just experiences and no corresponding material things is also simple and cannot be proven to imply a contradiction.
(Some self-professed identity theorists cheat. They make their view sound less implausible by writing of two “aspects” of neural events, or saying that neural events “lie behind” experiences, or that in experiences we “take a perspective” on neural events that is different from, and unavailable to, scientists who might be detecting the so-called same events with their instruments. But these palliative phrases all introduce some form of distinction between experiences and neural events, and they are not compatible with identity claims.)
My agreement that natural science does not explain appearances does not extend to Tallis’ favored way of arguing for this conclusion. That argument depends on “intentionality”, and the first thing to do is explain this word.
“Intentionality”, when a philosopher says it, means “Aboutness”. As in, your thought is about something. Of course, if you intend to do something – say, you intend to vote for candidate X – your intention is about something – in this case, it’s about voting for candidate X. But if you believe that Aunt Tillie is arriving tomorrow, your belief is about Aunt Tillie’s arrival. So, even though it’s just a belief and not an intention to do something, it has intentionality (as philosophers use this term) – that is, in plain English, it’s about something.
Some philosophers, including me, avoid “intentionality” whenever they can, and talk about aboutness instead, except when they discuss others who do use it. Many states besides intentions to act and beliefs can be about things or situations: these include hopes, desires, fears, doubts, supposings, wonderings, etc. One thing that makes aboutness interesting is that you can think about things or situations that do not exist. There are no unicorns and there are no men on the Moon at this writing, but that doesn’t stop anyone from thinking about those possibilities.
What about perceptions – are they about what is seen, heard, and so on? Tallis answers Yes, and this answer is a basic premise of the way he argues about appearances. My own answer is No.
This difference is fundamental, and it is a hot topic of discussion in the philosophy journals. A majority of philosophers are probably closer to Tallis’ view than to mine. There can be no hope of settling this issue in one blog post.
But it is relatively easy to provide a reason that raises some suspicion that seeing is very different from thinking. It’s a reason for separating appearance in visual experience from the processing of information about what is seen. And it is a reason that you can provide for yourself in your own home – as follows.
Sit by a window and look out at the buildings or trees or whatever is in the scene before you. (But if it’s a brick wall on the other side of a narrow alley, try a different window. You’ll need a scene where you can see something at significantly different distances.) Now, cover up one eye for about 20 seconds.
While you’re waiting, think about the character of your visual experience. I predict that you’ll agree that the world does *not* suddenly look flat. Nearby houses, for example, will still strike you as being seen as near, more distant houses as farther away. That may strike you as odd, because you may have learned that depth perception depends on cues from both eyes; and people who lose an eye do have some difficulty with such things as reaching for a glass of water. But there are many cues relating to distance. For example, you may know that houses in your neighborhood are roughly the same size. A distant house, however, takes up less of your visual field than a nearer one, and that helps you see it as more distant.
OK, now uncover your blocked eye. If you’re like me, you will experience a palpable restoration of a sense of depth. This too is somewhat puzzling: depth doesn’t dramatically disappear when you cover, but the restoration when you uncover is striking. I don’t know how to explain that, but it’s evident for me. (If anyone tries this and does not find what I find, I would be very interested to hear about it.)
What does this experience tell us? A point to note is that you will not have changed any judgments about what you’re looking at. Your thoughts about what is there will be the same. It is only a sense of depth – something like the difference between the 2D and 3D versions of movies – that is different. This difference is quite unlike a difference of opinion; it’s not a difference in what you think. It’s a difference in your visual experience.
It is almost routine in the philosophical literature to move from (a) the presence of depth in visual experience to (b) claiming that visual experience is about what is seen. But depth and aboutness are two different things. Visual appearances are one thing, judgments about what is seen are another. The judgments are often automatic, of course. You do not have to give yourself a conscious argument to get from appearances to things. You just effortlessly take it that you’re looking at a house, a car, an apple, or whatever. But the little experiment should help you see that the visual experience itself is a different thing from the judgment about what’s being seen.
[The article I’m responding to is by Raymond Tallis, “What Neuroscience Cannot Tell Us About Ourselves”, The New Atlantis, Number 29, Fall 2010, pp. 3-25. Thanks to Maureen Ogle for calling my attention to this article.]
Your Brain and You 