Classical Theism, Philosophy, and Religion Forum / Imagination as a perfect guide to possibility

**Posted by Ouros** 8/29/2018 4:22 pm

Hello everyone.

I was thinking about modal knowledge after reading a bunch of things about Husserl and his eidetic reduction,
It seems to me that "if we can imagine X, then X is possible" is clearly true. I fail to see how to form qualia in our mind could make us see an impossible word, even by mixing any of them.

So I tried to think about some counter-example, and I could found only one; a Penrose triangle:

But I'm not so sure, even if he's one of the so-called "impossible objects". Maybe some non-euclidean space could accodomate it?

What then is wrong: 1) the infaillibility of imagination as modal guide or 2) the impossibility of this figure?

I would bet on 2, but I'm curious about your views.

Last edited by Ouros (8/29/2018 4:22 pm)

**Posted by Greg** 8/29/2018 9:05 pm

When you imagine a Penrose triangle, what are you imagining?

On the one hand, clearly you can imagine that the world is such that you see such a thing. For this world is such a world. But then "such a thing" is just a particular two-dimensional image. So this isn't what we mean when we put forth the Penrose triangle as something imaginable but impossible.

What is meant is that if we see the Penrose triangle as a three-dimensional object--as we are inclined to see it, by seeing the shading as suggesting variations of depth and shadow, and by seeing each of the acute (in the two-dimensional representation) angles as right angles--then we are seeing it as something which is impossible. And that seems to be correct. The three "sides" of the Penrose triangle could not each be perpendicular to the others and form a triangle as the image impresses they do. (Though it should be possible in non-Euclidean space.)

**Posted by RomanJoe** 8/29/2018 9:31 pm

In fact, here's what happens to a Penrose triangle in reality:
https://upload.wikimedia.org/wikipedia/commons/thumb/3/38/Perth_Impossible_Triangle.jpg/500px-Perth_Impossible_Triangle.jpg

Last edited by RomanJoe (9/07/2018 9:03 pm)

**Posted by Greg** 8/30/2018 10:18 am

Greg wrote:
(Though it should be possible in non-Euclidean space.)

(As I think about it, though, when we typically imagine it, we are imagining it in Euclidean space.)

Here are some other candidates for impossible yet imaginable things. I can imagine that the Morning Star and the Evening Star were not identical. I can imagine that human beings speak unsystematic gibberish instead of their usual languages, yet go about their lives just as we do. I can imagine that water lack some of the chemical properties it has (say, those due to its polarity, like its cohesiveness--I can imagine, for instance, that water were more like non-polar liquids in not forming or forming less stable droplets).

**Posted by Brian** 9/07/2018 11:02 am

My intuition is that "if we can imagine X, then X is possible" is clearly false. Although I think a lot hangs on the definition of imagine.

For example I can imagine a woman who just had a hysterectomy giving birth to a child in 10 months. That's biologically impossible.

I can imagine a Hydrogen atom with 4 protons. That's physically impossible.

I can imagine Russel and Whitehead being correct that mathematics is derivative of logic. But that is logically impossible.

I can imagine an Acorn growing into a Rosebush. That is metaphysically impossible (on a standard reading of essentialist metaphysics).

I don't see any reason to think that imagination is a guide to possibility. Does anyone other than Marxists, for example, think a classless utopia is possible just because it has been dreamt up?