Tuesday, April 15, 2014

The Screen Argument, Re-Explained

I will now pose the Screen Argument as a question:

Where in the physical world does the image you observe when you look at things exist?

Think about it.

Where in the physical world does the image you are looking at right now exist?

First off, its not right in front of you. If it were anywhere in the physical world, it would be in your brain. The brain is what interprets the information sent to it by the eyes.

But is the image in the brain?

In a sense yes, in a sense no.

On the yes side, there are reactions going on in the brain that correspond to what you see in a 1 to 1 fashion.

On the no side, consider this: The image you see when you look at a tree contains the color green (if the leaves are green). If we dissect a brain, we don't find the color green. We don't find a picture of a leaf. We don't find a picture of a tree.

So, what is going on in your brain corresponds to, but IS NOT EQUAL to the image you observe day to day.

That image that you see day to day exists, though. There it is, isn't it? In fact, your visual experience of the physical world is tied to and dependent on that image. It is how you are reading this sentence right now.

But this sentence does not exist (in the form that you are reading it) in your brain. But it exists. But it doesn't exist in the physical world.

Therefore, the image you experience as you read this sentence does not exist in the physical world.

The same holds true for your senses of hearing, touch, and taste. I think a similar argument can be made based on your experience of thoughts and memories.

Conclusion: The image you experience of this sentence does not exist in the physical world (although it corresponds to activity in your brain).

5 comments:

  1. How does this information affect your understanding of the existence/non-existence of God?

    Augustine had a quote about scientists and philosophers in which he said (paraphrased) that the observations they made with their eyes are true and of merit, but they do not consider the God who gave them the ability to perceive and use their senses.

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  2. Josh,

    Nice post. A huge problem with materialists is that they don't understand that the correspondence between neural activity and the thing being perceived does not logically necessitate their identity. Also, because we are embodied beings, we must use our bodies and the world to convey ideas that we have. But this does not mean that the ideas that we attempt to convey through our bodies or the world - say, you drawing a painting on a piece of paper - is identical to the idea of the mentioned painting that we have "in our mind".

    These two things are the basic problems that I can see, at least right now, of materialism.

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  3. "But this sentence does not exist (in the form that you are reading it) in your brain. But it exists. But it doesn't exist in the physical world."

    I consider this an assertion without evidence. I don't see why any metaphysical explanation for our experience of consciousness is necessary.

    Subjective feelings are not a guide to objective truth. After all, "The first principle is that you must not fool yourself — and you are the easiest person to fool." (Feynman)

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    1. The evidence is that your are experiencing your visual field right now. You have direct access to the evidence.

      I absolutely agree that subjective feelings are not a guide to objective truth. My career as an MD/PhD depends on me not doing so. I heartfully agree with Feynman!

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