Friday, October 8, 2010

Update and Tyler Burge/Vision Science Primer.

       A little update before we get into the philosophy....
     Actually, I lied.  There's no update here cuz, every week pretty much follows the same pattern:  going to class, fantasizing about what I'm going to eat on my "cheat" day, studying, more fantasizing about cheat day, more studying, going to the gym, entertaining the occasional bachelorette/birthday party, hiking on Sunday and eating whatever I want that night! Repeat. 
     I guess what breaks the monotony more than anything is doing those parties.  Inevitably there's always something funny that happens.  At one of the parties on Saturday the mother of the birthday girl kept telling me (in jest) that she has lots of money and if I want to stay at her place and study, it's no problem she'll take good care of me.  Of course, this caused the birthday girl and her friends to have fits of giggles watching her mom flirt with me.  As I was getting ready to leave they put some merengue on (they were Latinas).  I pretended to be uber-gringo--when I'm working amonst Spanish speakers I usually don't let on that I understand them--and said "Oh! What is this kind of music?".  One of the girls, challenging me, said "I can teach you how to dance".  This was too good to pass up.  I pretended not to know what I was doing for a bit, then "POW!".  They couldn't believe this gringo stripper knew what he was doing.  Anyway, they loved it so much they tipped me and extra $40.00, which was nice.  Yay! Fist pump!
     Oh! I guess there is some bike got stolen from campus...and it rained that day.  Great, the last thing I need as a broke student is to buy what I already owned.  And that bike was a piece of crap...what were the stinkin' theives thinking? "Hey look! This one comes with a free water bottle!" Idiots...and so much for that extra $40.00

Tyler Burge, Philosophy of Mind and Visual Science.  
A Primer.

First watch these:

   This is a little overview of some of the stuff I'm studying in my philosophy of mind class.  Very cool stuff if you're like me and don't know too much about it.  Back in my undergrad we studied the major problems of philosophy of mind and some of the important historical movements in philosophy to try to solve these problems.  However, we never studied any contemporary accounts. The book we are studying came out in February this year, so you're not going to get much more contemporary than that...Anywho, I remember having two related thoughts while we were studying theories of mind in my undergrad class:  First, what do the philosophers of today think about this stuff?; and second, can't we have an orange mocha frappaccino--I mean--turn to empirical science to help sort through some of these important issues?  Guess, what? Tyler Burge is contemporary, and....whenever possible, he refers to vision science and perceptual psychology to form/support his arguments.  Cooooool!
     To quote a famous poet, "lets get it started in ha".  Burge is concerned with asking what it means to objectively represent the physical world.  You see, when it comes to sensory perception (for the sake of simplicity we will concern ourselves only with vision) there are a couple of problems.  The first problem is that of objective representation.  We do not perceive the external world directly.  Rather, we attribute properties/kinds/relations to particular objects in the physical environment through the mysterious inner workings of our perceptual systems.  So, if our perceptions are the products of our perceptual systems' inner workings, how then do we know that our perceptions of the world correspond to what the external world is actually like? The second problem is that of fallibility of the senses.  We know the senses can sometimes misinterpret input and produce an incorrect representation.  Consequences of this problem are determining why, when and to what degree we should trust our senses.  The third problem is called "the underdetermination" problem, the solution to which will help us with problem two.  The essence of the underdetermination problem is that there are an infinite number of different external stimuli that will produce the same representation.  How does our perceptual system "decide" which interpretation of the stimuli to represent, i.e. which property to attribute to an external object?  I want to focus most of my attention on the third problem because understanding/solving it helps guide us in the first two problems.

Objective Represention
    I'd like to begin with the short answer to the first problem, the problem of objective representation.  Burge proposes an argument from evolution.  That is to say, it is not unreasonable to suppose that our perceptual systems evolved to represent the external environment accurately.  For what would be the evolutionary benefit of representing the external environment as it isn't?  Side note, generally speaking we can use "accurate" and "objective" interchangeably when referring to successful representation.  There are cases where this is not true, but we'll set those aside for now.  

The Underdetermination Problem
     Yeah, I know I'm skipping problem #2 for now, but I'll get there.  Patience!  (Note to self, follow your outline, or create one you will follow...or write the body first, then give an outline...or...shut up and write!)  To discuss the underdetermination problem, I want to first introduce some terminology that will simplify explanations.  Distal Cause:  The three dimensional external environment that is the cause of a representation and that which the perceptual system aims to represent.  Proximal cause:  The two dimensional array of light in various degrees intensity on your retina as a result of a distal cause.
     Ok, got that out of the way.  So, here's how visual science tells us (visual) representation works.  A given distal object forms a certain 2D array on your retina.  The light in this 2D pattern stimulates certain receptors which send signals to the rest of your visual system.  A bunch of stuff happens in your brain, and voila! you represent a potential distal object, and you perceive that distal object.  The problem is this.  There are an infinite number of 3D distal objects that could produce the same 2D pattern on your retina.  A simple example:  A basketball at 1 meter from you face and a mini ping pong sized basketball at 15cm from your face will cover the same amount of your visual field.  In other words, the 2D array of light on your retina will be the same size for both.  How then does your brain know which scenario to represent?  How does it correctly gage the size? Also, how does it construct a 3D representation from only a 2D pattern on the retina? This is what underdetermination means, there are mathematically an infinite number of possible distal causes of a proximal light array.
     The short answer is that you are hardwired toward certain interpretations of retinal stimulations.  Your brain is hardwired toward certain interpretations of proximal input.  We are hardwired toward interpretations that are (or were during the time they evolved) the most useful for the organism. 

...Ok, going to have to finish this another day, it's almost 5am and I can't think straight anymore...good night!  Oh! check out these cool optical illusions.

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