Sunday, August 17, 2014

Close Your Eyes and See Sense Data?

I will not positively insist that we “see” anything when we close our eyes in a not bright room. If you prefer to say that we have a “visual sensations” or something of the sort, that is fine with me. There is at least something going on that permits us to make such descriptions as “there was a greenish blob that drifted down and left above a small, yellowish comma shaped patch.” Nowadays these experiences, or perhaps more accurately the content of these experiences, are called, by philosophers, “qualia.” Russell, G.E. Moore and others in the early 20th century would have called them “sense data.”

The friends of sense data were aghast when their critics proclaimed that sense data did not exist. What about those closed eye color patches? For those patches, I think we should more or less stick with the friends of sense data. Those patches do exist. We can report on them, and when we do so we use basic color, shape language.

However, sense data critics had the better of the overall argument. Sense data were supposed to be a much wider genus and far more important than our closed eye color patches. They were supposed to be the content of every experience. They were also, and this was of vital importance, the empirical ground floor of science. They were what observation came down to in the end if we were rigorously scientific and hard headed. They were the footings level of a foundationalist empiricism, the indispensable starting point of our knowledge of the world.

There were two properties of sense data that were supposed to equip them for this all important function. First, they were immediate experience in that they were right there on the surface of experience. They were what was in consciousness when we were having an experience. Second, they were immediate in the respect that they were not mediated by our prior beliefs, theories, or biases. It is for this latter reason that they could function as the uncontroversial starting point for science.

This far, however, we cannot follow the sense data theorists. The fatal flaw of the theory, as their critics pointed out with more or less clarity, was that the two kinds of immediacy come apart. Maybe they don’t come apart for the color blobs sensations with your eyes closed. Those blobs are what we are directly conscious of, and they seem minimally affected by our theories and biases. 

With our eyes open, however, we only rarely see anything like uninterpreted swatches of color. When I look at a penny from an angle, I don’t see a coppery ellipse; I see a circular penny at an angle. To try to get back to something like what the patches on my retina must have been like, I have to perform mental calculations. I almost always get these calculations wrong in any complicated scene. Unless you have gone through long hours of training in perspective drawing or are a spatial genius, you do too. This point was argued effectively by my teacher Norwood Russell Hanson. See his Patterns of Discovery.

Optical illusions work because what we are immediately conscious of is usually highly dependent upon our prior beliefs, theories, and experiences. What we seem to see here is one central circle considerably larger than the other.
 
This comes from a (usually very useful) processing heuristic in our brains of judging sizes by their relation to their environment. It is very hard to see the right central circle as the same size as the left – even after measuring. Covering up the circumambient circles will do it, and if, again, you are a spatial visualization whiz, you may be able to do this in your head. 

So if we want the sort of immediacy of what we actually see it is the immediacy of people, pennies, and optical illusions as they fool us. That is to say the contents of our consciousness are almost always highly theory laden. They are not pure and bias free. Thus they utterly lack the sort of immediacy that was supposed to make them the uncontroversial starting point for science. 

That there is no such thing as immaculate perception, as would be pre-theoretic data, is a point that post-modernism runs with – often to relativistic extremes. I will not here expatiate on where they go astray, though go astray they certainly do. The path is long from the theorized nature of all data to such conclusions as that there is no such thing as objective truth. 

But back to sense data and our closed eye starting point. Is it right to say that we see sense data when we close our eyes? The harm of saying that we do is not great and it would be little worse to say that we experience sense data in a dense fog or a very dimly lighted room or when first awaking. Even in these special cases, however, we have to be careful not to go too far in the direction of sense data theory. 

You may be tempted to say that you are certain or that you couldn't be wrong about what you see with your eyes closed. It is true that you just experience what you experience with your eyes closed. There is nothing you could be wrong about, but for that very reason truth talk and certainty talk are out of place. It is only when you start describing your experience in terms of blobs and patches that you first have something to which truth or falsity and certainty or uncertainty could apply. Yet once you get to this verbal phrase, can't some error creep in? Couldn't you use the word “patch” where “curtain” would be more apt? Maybe that blob actually started to the left of the comma shaped patch and drifted straight down. It surely isn't impossible that you could get such a detail wrong. What we see with our eyes closed can be pretty complicated.

So even the experiences that are most sense-data-ish, do not have all the properties they were supposed to have on sense data theory. More important, science clearly does not start out from the likes of the colors you experience with your eyes closed or of a dim room upon awakening. Sense data theory, although it contained a smidgen of truth, is mostly false, and anyone whose use of “qualia” edges towards sense data theory is going to tend to mislead us.



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