Reason as the Leading Motive

Descartes would go Nuts!

Posted by Jerry on October 10, 2006

UPDATE: My friend at work (the one I spoke highly about regarding his gifted skills in website design and online artwork) figured out the mechanics behind the illusion. He correctly pointed out that because sqaure “B” is surrounded by much darker squares (made much darker by the shadow), we percieve “B” to be lighter than square “A,” which is surrounded by much lighter squares (because they are mostly outside the shadow of the cylinder).

Thus, in the second picture below, squares A and B and the grey strip are all of the same shade. [Deep, I hope you find this convincing, though I wouldn’t fault you if you don’t.] 🙂

Diana Hsieh blogged about some optical illusions that are posted on Hemmy.net.

While I was checking out some of the really cool optical illusions, I came across this one below. It’s the most mind-boggling illusion ever! I’m still baffled–in an stupefied sense! I mean, I rationally know the reason behind the illusion (I’ll state them at the end of this post), but in a purely “sensory-perceptive” sense, I am stupified! This confirms it: I am now officially a Cartesian! 😉


Quoting from Hemmy.net:

This is an optical illusion by Edward H. Adelson who is a professor of Vision Science at MIT. The above picture shows that the squares marked A and B are of the same gray shade. Don’t believe what your eyes are telling u?

Here is the answer to cast off your doubt.

Now, I’m sure that the “mechanics” behind the illusion has to do with the interplay of lighter areas and the darker areas–the squares that are shadowed under the green cylinder and those that are not. Nonetheless, the illusion is so incredibly potent that, were I to rely only on my sensory-perceptive level of cognition and ignore the rational integration of my perceptions with my existing body of knowledge, I would readily be convinced of its reality.

This reminds me of David Kelley’s illuminating work in Objectivist epistemology–a realist theory of perception, which he formulated with assistance from Peikoff, who of course had learned of it from Rand. While Kant in effect had declared that because we have eyes, we cannot see, and because we have ears we cannot hear, and because we have consciousness we can never know reality, Ayn Rand demonstrated that the identity of an entity dictates what it does. Thus, our eyes will see in a manner that is appropriate to it. Human eyes see visible light of a certain wavelength. Other creatures may see objective reality in other wavelengths of light. However, humans and other creatures all percieve the same objective reality, but see them in different forms. An alien from Mars may describe seeing the world in green hues because his visual apparatus maybe designed as such; nonetheless, the world that he perceives is the same world that we would percieve as humans with our eyes. The alien might have a set of concepts developed to describe the world as he sees it–which is still objective because his concepts correspond to reality, just as we are being objective in our description of a world through valid concepts that we have formed in our contexts in relation to reality.

Anyway, the point of this post was to discuss the kinds of tricks our perceptual faculties can play, which highlights the importance of integrating knowledge hierarchically with existing knowledge, foundational principles, and being consistent with reality.


5 Responses to “Descartes would go Nuts!”

  1. Deep said

    Are you sure about the grey strip shown on the chess board in the second picture? I seem to perceive a change as I go down the strip, from a darker tinge to a lighter one.

  2. Ergo said

    ha! I feel that too. I’m not sure if that’s objectively an aspect of the grey strip, or the effect of the shadow of the green cylinder nearby, or simply an optical illusion in its entirety! 🙂
    Isn’t this why it *is* so fascinating!?

  3. Mark said

    No more postings like this, Ergo! It’s freakin’ me out, man!


  4. Deep said

    I am sure it is the strip. Maybe we should check the pixel map of the image. 😎
    But yes, it is fascinating as all optical illusions are.

  5. Jason said

    Ay carumba! You hurt my brain! But in a good way!

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