Saturday, November 18, 2017

--- Notes on perception ---

[Unlike extension, secondary qualities, such as colors and sounds, exist only as sensations in the mind. In material bodies such qualities] are nothing but the powers those substances have to produce several ideas in us by our senses; which ideas are not in the things themselves, otherwise than as anything is in its cause.

John Locke

We have sense organs like eyes, and ears. Those instruments pick up energy fluctuations in our surroundings and sends impulses up nerves to the brain. To this point, what's going on is electrical charges traveling along cell walls and chemicals being secreted and sensed by other cells. Does that sound like what we sense about our surroundings? We know these things are happening because we can measure them.

The brain decodes these impulses into other impulses with converge on certain parts of the brain things. Things happen and we can measure them. Strange things often happen. Have you ever heard of "blindsight?" There was a movie based on it. I've experienced blindsight before.

I have a rare condition known as "acephalic migraine". An acephalic migraine is a "migraine without the headache." I have the things that lead up to a migraine headache (they're called "prodromals") and I have the hangover-like feeling afterward. What I don't have is the actual headache - I'm not complaining.

One common prodromal is neuronal blindness. It starts as pixelated sparkling lights in the periphery of my vision and it spreads until all I can see are sparkling lights. I'm blind - but I can, for instance, drive a car.

I was once stuck in rush hour traffic in downtown Montgomery when the little twinkling lights began to invade my vision. I was in the inside lane and I couldn't get out of the traffic fast enough. I was completely blind, yet I drove to the next intersection and off the interstate into a parking lot and stopped until my vision cleared.

I couldn't see but, obviously, somewhere - in my head, in the ether, somewhere, my brain was putting everything together into the same visual representation I'm used to. My body responded as it usually does. The only difference is, I couldn't see!

There is no material manifestation of the experience of sensation in our brains. There is nothing you can point at to say, "This is real." Sensation is what neurologists call and "emergent quality". It springs from what is actually happening but it's only nature is that of information - no page, no computer screen, just neurons firing, nothing you could put your finger on, not "real".

Our sensation of reality, as real as it seems, is not real - it's a hallucination. We hope it bares enough of a resemblance to reality so that we can get along, but it's not perfect. At the everyday level, there are illusions. It gets really troublesome when there are pathological process and the person affected can't distinguish between the reality and the errors.

It sounds scary but, consistency bares out that our versions of reality are, indeed, accurate enough. And,  they give us better than reality. Consider, there are different wavelengths of light, but there are no colors in reality. Color is a result of how our eyes and brains decode different kinds of light. Different people see colors differently. Color blindness is much more common than most people think.

According to Wikipedia, about 8.7% of humans have some form of color blindness. But I can tell that my right eye sees greener than the left eye, which makes things look bluer, and I test out fine in regard to color vision.

But our "hallucinatory" view of the world gives us color! Our brains color code our world for us.

I don't feel short-changed at all.

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