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Potentates II Presentation

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Saved by peterga
on November 8, 2009 at 1:57:14 am
 

The idea of this presentation is to try and make us a little more cognizant of how much of our perceptions are illusion, and to encourage us to bear that in mind a bit more when our considerations of our selves and our world.  To open the topic of illusions and how our brains tend to fool us, I'm going to take a look at a few puzzles.  Most of these and most of what I have to say in this presentation is something we have discussed before, but I'm hoping that even if there is nothing new to you here, these reminders will encourage different ways of thinking about our perceptions and our misperceptions of not just colors and sounds, but of things like morality and free will.

 

<insert puzzles>

 

Vision and color perception are the primary sensory proxy for understanding consciousness, and like other senses and consciousness itself, it subjects us to many illusions.  I'd like to talk about three different levels on which illusions affect our understanding of the world:

  1. Illusions in which we can easily recognize how reality differs from our perceptions
  2. Illusions where one is aware of the the difference between the illusion and reality (i.e. we don't recognize it as an illusion at all); and
  3. Illusions that we understand intellectually, but which we cannot prevent from continuing to fall victim to in some way

 

Let's start by considering what we refer to as  optical illusions.  With the typical optical illusion, it is readily explained to us how our perceptions differ from reality.  E.g. by fixing our gaze on specific portions of the imagine, it only takes us a few moments to figure out that nothing is actually moving in the Rotating Snake illusion or the Blue and Yellow Dots illusion   Note that recognizing the non-moving reality of these pictures does not stop us from perceiving motion when we look at them, but with the limited times we are exposed to them, when we see them in the future we immediately think of them as illusions.

 

This is somewhat different from more persistent illusions such colors being properties of objects in the external world (i.e. external to our brains).  We may intellectually recognize that while these objects have shape and chemical properties, colors are something are invented entirely within our brains, and are a code the brain uses to represent the objects, not qualities of the object itself.  But even so, I submit that we cannot keep assuming, at some level of consciousness, that the fire engine is red.

 

We'll return to this later, but for a moment let's consider how perceptions like this led to misperceptions of how vision works.  For example, let's consider the belief that visual perception works via tiny emmissions from the eyes.

 

This "extramission theory" of vision dates back at least as far as Greek philosopher Plato (427-347 B.C.), who spoke of a "fire" that emanated from the eye during vision, which "coalesces with the daylight ... and causes the sensation we call seeing."  Later, Greek mathematician Euclid (circa 300 BC) described "rays proceeding from the eye" during vision."   ("50 Great Myths of Popular Psychology," p34)

 

Now you may think that this type of thinking about vision strictly predates modern optics, and that eyes emitting rays now exists only in comic books.  But the belief that we see by emitting something from our eyes remains quite common.  57% of elementary school children say that something comes out of our eyes when we see.  So something about this idea seems to be strangely intuitive.  And while this belief declines with age, surveys have found that 30% of more of adults also claim the belief when asked if the eye emits rays or particles that enable it to ee objects.  (Ibid)

 

Beliefs about visual perception that have been soundly debunked by science are surprisingly common.  E.g. when I googled "primary colors," one of the top results I got was this definition from About.com.

 

Let's consider the basic stages of understanding how color perception works.  It seems to me that these are:

  1. Colors are simply intrinsic properties of objects and percieving colored objects is simply seeing the world as it is.
  2. "The tree is green because it reflects green light"
  3. The brain simply maps certain colors to certain light frequencies
  4. Modern scientific understanding

 

#1 is simply the intuitive view, the one pretty much shared by the entire world before Newton.

 

#2 is the view we learn in school, and which leads to the belief that light wavelengths somehow contain color.  We've known that this is false since Newton himself ("The color is not in the rays." -- Isaac Newton), but we keep misleading school children in this way -- and my impression is that many if not most educated first world citizens have never really recognized that colors do not exist at all except in our brains.

 

#3 is critical, in my view, for a basic understanding not just of our perceptions, but for a basic understanding of the nature of the world.  I will return to this huge step in  a moment, but for now I'd like to note that shortcoming that still exists in this view -- i.e. the misperception that color perception works like a spectrometer, and that the brain simply correlates certain wavelengths fo light with certain colors in our brain. 

 

First of all, the brain never receives information of a "pure" color or a single wavelength of light. 

 

This is an especially quaint anachronism from the 18th century, and it is wrong from several points of view. If a paint really were "pure" and only reflected a single wavelength of light (which is the "purest" possible color stimulus), the paint would have a luminance factor near zero and would appear blacker than the "purest" black paint.    (handprint.com)

 

Light information to the brain always comes in the form of the numbers of the three types of photoreptors sending strictly binary information ("Yep, I got one of those") to the brain.  It always arrives with and contrasting information and absolutely relies upon this to create color.

 

Second, if the brain just consistently mapped specific lightwaves to a specific color, this would have been of so little use that we almost certainly would not have evolved color perception at all.  Consider that color perception arose to accomplish tasks like telling ripe fruit from unripe and identifying a "red" fruit within "green" foliage.  Now consider how hopeless that task would be if color perception worked like a spectrometer.  After all, as atmospheric conditions change during the day, entirely different wavelengths of light are bouncing off that fruit.  Similarly, as the earth rotates throughout the day and the sunlight slants though the atmosphere at different angles, it's diffused rays are again resulting in entirely different wavelengths of light landing on and bouncing off the fruit.

 

Color perception would be of little or no help if we never knew what color the fruit and what color the background were going to be at any given moment.  What makes color a useful encoding method is "color constancy," i.e. that facility of our brains to constantly make an apple look red -- regardless of the atmospheric conditions -- by comparing the light bounding off it to the light bouncing off the things around it, and using this to continually adjust which wavelengths it encodes as red.  A "perfectly accurate" encoding of wavelengths, ala a spectrometer, would be of little or no use.

 

Recognizing the complexities in the correlation of perceptions to the real world -- and recognizing that these perceptions are designed not to give an accurate view of the world, but rather to give a useful one, helps reinforce the critical lesson of step 3 and our understanding the differences between what really exists in the outside world and what exists strictly within our brains to help us function in that world.  This help is welcome because it is not easy to bear this in mind.  It is difficult to "grok" this even if we understand the explanation.  Our tendency is to sense that light is giving us information that lets us determine the true color of an object, not that color is something made up in our brains to give us infomation about the shape and chemicals of the object.

 

And it's the same for the other senses.  No matter what our intellectual understanding of the science, we still tend to think on some level that smells and sounds exist in the outside world.  But of course smells and colors are no less subjective than other perceptions like pain.  A sharp knife may correlate to pain when it strikes the body, but pain does not exist outside our conscious minds.  In exactly that manner, colors have correlations with light waves, but the correlation doesn't make them exist in the outside world, any more than pain does.

 

And here we get to the next step I wanted to encourage in thinking about what we are, because this type of very strong illusion is not limited to just the classic five senses.  Increasingly science is leading us to believe that similar illusions mislead us about things like intentionality and the unity of the self.

 

 

 

 

 

 

 

 

 

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