[spam] Re: Perceptual Illusions

CSGnet Archive CSG2006
1

[From Rick Marken (2006.08.29.0825)]

Bill Powers (2006.08.29.0715 MDT)--

The movers arrive today.

Oy. Good luck. I hope it goes smoothly.

Rick Marken (2006.08.28.1600) --

OK. I think we can all agree that perception is reality and reality is the current state of our scientific models.

Why am I not happy with that?

Because I was waxing poetic. What I should have said is "perception is what we take to be reality while the best we can do at knowing the nature of the presumed external reality that is the basis of our perception is to build scientifically tested models of that reality" .

Ah, same reason I give for determining what is an illusion: Things which are equal to the same thing (or each other) are equal to each other

Could you expand on that a little? How does that apply to common visual illusions, like the Necker cube, Muller Lyer (<--> >--<), stick bent in water, etc.

Directly Perceived Reality is the part of Real Reality that can be experienced. Experience can't be denied. If you see a pink elephant in the corner of the room, there is no way to deny that you see it, the room, the corner, the label "pink elephant," and so on. That experience is happening.

Deduced Reality is a subset of Directly Perceived Reality. It is the set of all statements (thoughts, etc.) about other parts of directly perceived reality. "That pink elephant is not real" is a statement belonging to deduced reality.

I like it! So what we call an illusion is a discrepancy between Directly Perceived Reality and Deduced Reality. Is that right? Is it fair to say, then, that Deduced Reality is what most people think of as Real Reality? And would it also be fair to say that, to a large extent, the study of perception (in psychology and physiology) has largely been concerned with determining the relationship between Directly Perceived Reality and Deduced Reality? Isn't that basically what psychophysics is about, for example?

Models belong to deduced reality.

What other aspects of Deduced Reality are there besides models? If, for example, I deduce that a stick remains rigid when placed in water, isn't that kind of a model of stick behavior? So when I see the stick bend at the surface, don't I treat that as an illusion because the Directly Perceived Reality (bent stick) is inconsistent with the Deduced Reality (my model) of the stick as rigid?

I love the distinction between Real Reality, Directly Perceived Reality and Deduced Reality. If I include it in any writing I will give both you and Bob Clark credit for it. It's a very helpful distinction -- or so I deduce, anyway;-)

Best

Rick

···

---
Richard S. Marken Consulting
marken@mindreadings.com
Home 310 474-0313
Cell 310 729-1400

2

[From Bill Powers (2006.08.29.1315 MDT)]

Rick Marken (2006.08.29.0825) --

Ah, same reason I give for determining what is an illusion: Things which are equal to the same thing (or each other) are equal to each other

Could you expand on that a little? How does that apply to common visual illusions, like the Necker cube, Muller Lyer (<--> >--<), stick bent in water, etc.

Take the last one. You see a stick apparently bent in the middle. You take a yardstick which you know to be stiff and straight, and align it with the part of the stick in air, and you see that the part of the yardstick that's under water is also aligned with the part of the stick that's under water.
Directions that are equal to the same direction are equal to each other. If you want to entertain other hypotheses (all objects bend at the point where they go under water) you'll have to think of other tests.

With the Muller Lyer illusion, you just measure both line segments with the same ruler, or a compass, or cut one segment out and place it over the other.

Directly Perceived Reality is the part of Real Reality that can be experienced. Experience can't be denied. If you see a pink elephant in the corner of the room, there is no way to deny that you see it, the room, the corner, the label "pink elephant," and so on. That experience is happening.

Deduced Reality is a subset of Directly Perceived Reality. It is the set of all statements (thoughts, etc.) about other parts of directly perceived reality. "That pink elephant is not real" is a statement belonging to deduced reality.

I like it! So what we call an illusion is a discrepancy between Directly Perceived Reality and Deduced Reality. Is that right? Is it fair to say, then, that Deduced Reality is what most people think of as Real Reality?

Yes.

And would it also be fair to say that, to a large extent, the study of perception (in psychology and physiology) has largely been concerned with determining the relationship between Directly Perceived Reality and Deduced Reality? Isn't that basically what psychophysics is about, for example?

Yes

Models belong to deduced reality.

What other aspects of Deduced Reality are there besides models?

Deduction implies logic, to academics. But to other people it means any way of talking that leaves you convinced of the truth of some proposition, like "God created the universe." One might call that a model, but it doesn't have the characteristics of what I call models. Then there's the pernicious fallacy which in Latin is given as "Post hoc, propter hoc" (After which, therefore because of which). A flash of lightning is followed by thunder: therefore thunder occurs because of lightning (pretty close). Right after I opened the window this morning, a magpie flew past. Therefore magpies fly past because of my opening windows (not likely). The latter rule, however could become a belief, which I would count as part of deduced reality, stretching the meaning of "deduce" a little. Maybe "believed reality" would be better.

If, for example, I deduce that a stick remains rigid when placed in water, isn't that kind of a model of stick behavior? So when I see the stick bend at the surface, don't I treat that as an illusion because the Directly Perceived Reality (bent stick) is inconsistent with the Deduced Reality (my model) of the stick as rigid?

Yes.

···

I love the distinction between Real Reality, Directly Perceived Reality and Deduced Reality. If I include it in any writing I will give both you and Bob Clark credit for it. It's a very helpful distinction -- or so I deduce, anyway;-)

Best

Rick
---
Richard S. Marken Consulting
marken@mindreadings.com
Home 310 474-0313
Cell 310 729-1400

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3

[From Rick Marken (2006.08.29.1700)]

Bill Powers (2006.08.29.1315 MDT)

Rick Marken (2006.08.29.0825) --

So what we call an illusion is a discrepancy between Directly Perceived Reality and Deduced Reality. Is that right? Is it fair to say, then, that Deduced Reality is what most people think of as Real Reality?

Yes.

And would it also be fair to say that, to a large extent, the study of perception (in psychology and physiology) has largely been concerned with determining the relationship between Directly Perceived Reality and Deduced Reality? Isn't that basically what psychophysics is about, for example?

Yes

If, for example, I deduce that a stick remains rigid when placed in water, isn't that kind of a model of stick behavior? So when I see the stick bend at the surface, don't I treat that as an illusion because the Directly Perceived Reality (bent stick) is inconsistent with the Deduced Reality (my model) of the stick as rigid?

Yes.

Well, finally I did well on a PCT test. 100%. Whoppee!

Thank you, Professor Powers.

Best

Rick

···

---
Richard S. Marken Consulting
marken@mindreadings.com
Home 310 474-0313
Cell 310 729-1400