krylex wrote:
My biggest question is: Where did the fuss originate?
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Angel On Crack wrote:
Hrm. Because I lack the will to go back through seven pages of pedantic nonsense, "googled" information and misquotes, I'm just going to give my own. If you don't like it, then it's because you're unreasonable, irrational, an idiot, or all three.
Or further back,
IcyMonkey wrote:
Descartes was also a wanker.
Neither probably made entirely seriously, but also perhaps not
quite within the full spirit of Debate Club. Moving on...
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Well, I couldn't remember the minor note I wanted to add to this thread, but now I do. Funny, that.
Anyway, demonstration time! (This is old, but I'll get to why I find it useful in a moment):
1. Get a blank sheet of paper.
2. Place two nice big dots on it, spaced about 1¼ inches apart horizontally.
3. Close your left eye and stare at the left dot with your right.
4. Touch the piece of paper to your nose and slowly move it away until the right dot disappears.
That's your optical blind spot (no relation to the "blind spot" not covered by a car's mirrors). It's where the optic nerve interrupts the retina, meaning you can't see anything at all in that spot. It's been there every minute of your waking life. You just don't normally notice it because your brain takes the visual data from the area
around the blind spot and fills it in with something it thinks will look natural (in this case, more blank white). If you use two long vertical lines instead of dots, you won't see a gap in teh right line no matter where you move the paper even though the blind spot is still there, because your brain sees a line on both sides and just assumes is continues through the spot, and so draws it in.
By itself, this doesn't disprove objective reality of course, but the fact that ours brains are able to do this so seamlessly is an interesting example of just how much processing our senses go through before reaching our "consciousness". To use another example, images actually come from our retinas upside-down, and our brains have to flip them.
Even if one accepts the idea of an objective reality which informs our senses, there would certainly seem to be a case for our
experience of that reality to be at least in part a construct of our own minds. And these examples are just at the basic mechanical level of perception. When you factor in the higher-level issues of interpretation, memory, etc., it's a wonder people are able to agree with each other on anything at all (unless you take into account the normalizing effects of societal factors, in which case it becomes more understandable).
I like the above example more than most "optical illusions", because it sort of smacks you in the face with the nature of your own visual perception more forcefully than simply being fooled into thinking, in an intellectual manner, that one line is longer than another when it's not or something.