A Conversation for h2g2 Philosopher's Guild Members Page

h2g2 Philosopher's Guild

Post 321

chaiwallah

I also read the article on the Universe/Holograph idea in the latest Scientific American. Seriously difficult technical stuff, requiring a knowledge of information theory/physics I totally lack. But I think the underlying principle is probably graspable, eventually, even if the concept is totally mind-boggling. I intend to give it another couple of goes.

Presumably the holograph principle is well enough known and understood not to need repeating here? What is interesting is that this idea is now becoming mainstream. Fritjof Capra ( I think ) writing in the 1980's proposed that material reality results from interference patterns in energy wave-functions ( which is basically what a hologram is, when projected from a holographic plate by laser light.)

But then they say that if you think you understand contemporary quantum physics/cosmology, you've probably got it wrong!


h2g2 Philosopher's Guild

Post 322

Researcher 185550

I am afraid I do not understand the holograph principle.

Please educate me smiley - smiley.


h2g2 Philosopher's Guild

Post 323

chaiwallah


OK, Roadkill, I'll do my best. It's one of those things I understood a few years ago, when I was reading a lot about physics, and which my brain hasd now dumped intio the fog department of fading memory. But I'll do my best.

A holograph is a photograph taken using a beam of laser light split into two (an object beam and a reference beam) which illuminate an object and record its image on a glass plate.

However, unlike a conventional photograph, the actual impression on the glass plate is an interference pattern ( caused by the re-joining of the reference beam and the object beam .) In order to see the image, the plate must be illuminated by laser light like the original reference beam. Then the "original" object can be viewed, as it were through the glass plate in three dimensions! Or the image can be projected as a three-dimensional image through the glass plate (think of Star Wars.)

Curiously, if the glass plate is broken, every fragment of it still records the full image of the object.

Its relevance to the Scientific American article is that only a holograph records a full three-dimensional image in two dimensions. Literally. If you turn a holograph, you can see "round" the object.


h2g2 Philosopher's Guild

Post 324

World Citizen

I didn't make it through the entire article, but basically, I think, what it is is that we could be in something flat, but just perceiving the world as 3D. Wait, does that make any sence? If I got the wrong idea, please correct me.


h2g2 Philosopher's Guild

Post 325

Researcher 185550

smiley - cheers Thanks very much.

Kind of like, I have a friend who has a rare vision disorder, in that he doesn't see 3D. It's like he's right, and for the rest of us the 3D is a construct of our brains?


h2g2 Philosopher's Guild

Post 326

chaiwallah


It's not as simple as not seeing in 3-D, because our tactile senses also register depth, as when you put your fingers round the neck of a bottle of beer.

As an artist I deliberately suppress 3-D vision when drawing, By squinching up my eyes, as this allows me to see more clearly the "negative" shapes/spaces around things as I draw, but it doesn't mean that 2-D is more "real" than 3-D in my perception.

The Universe/holograph article is going deeper than that, dealing not just with our common-sense-perception of 3-D space, but with the fundamental principle that the limits on the amount of information contained within a system, such as our "spherical" universe depend not on its volume ( as commonsense would lead you to expect ) but on the surface area. This is because any mass large enough will ultimately collapse under gravity to form a black hole of infinite density, but limited surface area. I haven't got the magazine here beside me, or I would try to spell that out more clearly ( if I understood it correctly!)


h2g2 Philosopher's Guild

Post 327

chaiwallah


PS, But you could say that all our "experience" is a construct of our brains.

A classic example being colour perception.

Here's the acid test.
Q. How can a colour TV produce the colour black through radiation?
A. It can't and doesn't.

Turn off your TV. The colour of the screen is greyish, and that's the darkest it can get. Your brain constructs black by comparison with the other colours surrounding it. This principle is a trick well known to painters, who can amplify the effect of one colour by putting it next to its complimentary colour ( the Impressionists made a cult of this ) thus red looks more intense next to green, blue beside orange, yellow beside purple.


h2g2 Philosopher's Guild

Post 328

Researcher 185550

I am out of my depth.

What I mean is, you see 3D as a construct of your brain in a 2D universe. Hence your fingers also feel 3D and your ears will register where sounds come from as though the universe were 3D.

I am confused though.


h2g2 Philosopher's Guild

Post 329

chaiwallah


Me too. G'night.


h2g2 Philosopher's Guild

Post 330

toxxin - ¬°umop apisdn w,I 'aw dlaH

Hello World. Hehehe. Here are the details of just about the world's (!) most popular introductory philosophy volume, as used by first year university students everywhere in the erm ............ :
J Hospers: 'An Introduction to Philosophical Analysis', Routledge (4th edition)


h2g2 Philosopher's Guild

Post 331

Tommy Mac

Tommy Mac
'Never test the depth of water with both feet'


h2g2 Philosopher's Guild

Post 332

Tommy Mac

Tommy Mac
Ah ! How fickle is the roving eye '


h2g2 Philosopher's Guild

Post 333

Recumbentman

Thank you Tommy Mac.

This 2D/3D theory looks quite like De Selby's theory* of the sausage-shaped earth. The earth, according to De Selby, appears spherical to us because we lack the ability to look 'along its barrel'. All empirical tests we can do, such as setting off to circle the world, lead us to believe we are right, but we can't see that all we are circling is one slice of the sausage. De Selby spent much of his life vainly trying to effect the arcane right-angle turn that would set him off along the length of the sausage.

*Reference: The Third Policeman, by Flann O'Brien.

A bit like Plato's philosopher who learnt how to turn his head in the cave of shadows, thus seeing the projector while all around him saw only the picture show.

After all, computer memory is essentially one-dimensional (serial) and yet we can present it to ourselves as two and three-dimensional info, four-dimensional when we add change over time. Cinema film is a series of stills which we interpret as (construct into) moving pictures. De Selby experimented with this phenomenon too, making extensive journeys by means of observing, in precise sequence, carefully selected picture postcards. He also experimented with parallel mirrors, noting that the image he saw was of himself (the observed) slightly younger than himself the observer. He managed to see himself with the aid of a powerful telescope as a beardless boy of twelve, but could go back no further than that due to the curvature of the earth and the inadequacies of the telescope.


h2g2 Philosopher's Guild

Post 334

Mal

Please type in your name and a Philosophical Phrase to join.
Fnord Prefix
"You're living in a dream world..."


h2g2 Philosopher's Guild

Post 335

Tommy Mac

If you ask a politician a simple question ,be prepared to listen to a speech in reply.

Tommy Mac


h2g2 Philosopher's Guild

Post 336

Tommy Mac

Tommy Mac
If you ask a politician a simple question , you must be prepared to listen to a major speech in reply.


h2g2 Philosopher's Guild

Post 337

Researcher 185550

smiley - biggrin

Reminds me of the Cigar shaped theory of the galaxy.


h2g2 Philosopher's Guild

Post 338

Recumbentman

Cigar shaped theory of the galaxy smiley - huh
Please enlighten.


h2g2 Philosopher's Guild

Post 339

Researcher 185550

It's about the reason the Solar system is shaped as it is. Astronomers seem to think that our system is a very unusual shape- thin at the edges, thick in the middle. Someone (I forget who) theorized that were two stars to pass very close to each other, one might draw out a cigar- shaped blob of matter from the other, which would eventually cool and form into planets. It was discredited because:

1) It is very unlikely that two stars will pass that close together
2) If they do, they'll probably crash
3) Even if they don't crash, the cigar- shaped blob is more likely to form into one huge planet, not lots of smaller ones.
4)Of the Church- because if two stars do pass close to each other, don't crash, do draw out a cigar- shaped blob, and then the blob cools into separate planets once, it can happen again. Which might mean that we are/will not be alone, or that we are a second sentient life forms to emerge in the universe.


h2g2 Philosopher's Guild

Post 340

Mooing Platypus (formerly known as Gaia)

Well, my name is Gaia,

and a phrase.....hard to decide.......

"If liberty means anything at all, it means the right to tell people what they do not want to hear."
-- George Orwell


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