What is reality?
January 23, 2011 8:13 AM Subscribe
Horizon asks "What is reality?" -- youtube for links for those outside the UK: 1, 2, 3, 4. It's a hard question. To help you answer it, Stanford has a set of free courses available on line by Leonard Susskind:
General Relativity, Cosmology, New Revolutions in Particle Physics, Quantum Entanglement, Special Relativity, Classical Mechanics, Statistical Mechanics, The Standard Model. (Each link is to lecture 1 of a full college course of a dozen or so lectures.) If you need help with the math, the Khan Academy should help get you up to speed.
"Imagination is the one weapon in the war against reality." - Jules de Gaultier
posted by fairmettle at 8:40 AM on January 23, 2011
posted by fairmettle at 8:40 AM on January 23, 2011
And for another perspective on just what might be meant by reality, one from the other of the "two cultures", there happens to be a Stanford project for that too. The Stanford Encyclopedia of Philosophy is probably the most useful philosophy tool on the Web. It's huge, well written, thorough, and becoming the standard reference for philosophy. It's one of the finest examples of open access humanities scholarship I've ever encountered. It similarly covers the topics of relativism, quantum mechanics, and the cosmological argument. Compare and contrast.
posted by Toekneesan at 9:11 AM on January 23, 2011 [7 favorites]
posted by Toekneesan at 9:11 AM on January 23, 2011 [7 favorites]
The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents. We live on a placid island of ignorance in the midst of black seas of infinity, and it was not meant that we should voyage far. The sciences, each straining in its own direction, have hitherto harmed us little; but some day the piecing together of dissociated knowledge will open up such terrifying vistas of reality, and of our frightful position therein, that we shall either go mad from the revelation or flee from the light into the peace and safety of a new dark age.
posted by Artw at 9:14 AM on January 23, 2011 [13 favorites]
posted by Artw at 9:14 AM on January 23, 2011 [13 favorites]
Nobody post until they've seen all the vids!
j/k. I'll have to check these out when I have the time.
posted by delmoi at 9:19 AM on January 23, 2011
j/k. I'll have to check these out when I have the time.
posted by delmoi at 9:19 AM on January 23, 2011
It would take about 300 hours or so to watch all the videos, I think. (No exaggeration)
posted by empath at 9:22 AM on January 23, 2011
posted by empath at 9:22 AM on January 23, 2011
I watched this, and then had a (probably stupid) question--when Einstein and Bohr were debating whether or not the moon existed when no one was looking at it, does the later development of radiocarbon dating techniques pretty much answer that question? Seems to me the moon could be popping in and out of your field of perception all you like but dating objects from its surface would show how long it had existed?
posted by SockyMcPuppet at 9:32 AM on January 23, 2011
posted by SockyMcPuppet at 9:32 AM on January 23, 2011
Nobody post until they've seen all the vids!
Multiple you's in parallel universes may already have. Or, you may have, but your consciousness confines you to an instant, in which can't see a past or a future.
posted by marvin at 9:40 AM on January 23, 2011 [1 favorite]
Multiple you's in parallel universes may already have. Or, you may have, but your consciousness confines you to an instant, in which can't see a past or a future.
posted by marvin at 9:40 AM on January 23, 2011 [1 favorite]
Artw wrote The most merciful thing in the world, I think, is the inability of the human mind to correlate all its contents.
Which is why watching BBC Horizon makes you go insane.
posted by New England Cultist at 9:41 AM on January 23, 2011
Which is why watching BBC Horizon makes you go insane.
posted by New England Cultist at 9:41 AM on January 23, 2011
Is it rude to point and wave at the same time?
posted by run"monty at 10:01 AM on January 23, 2011 [6 favorites]
posted by run"monty at 10:01 AM on January 23, 2011 [6 favorites]
dating objects from its surface would show how long it had existed
Just as long as someone is looking at the data.
posted by Balisong at 10:08 AM on January 23, 2011 [2 favorites]
Just as long as someone is looking at the data.
posted by Balisong at 10:08 AM on January 23, 2011 [2 favorites]
@SockyMcPuppet: I've never really read anything complete about this debate, but I think that it is related to the problem of measurement in Quantum Mechanics.
In essence, the act of making a measurement in Quantum Mechanics changes the system drastically. Depending on what you measure, you can give the system a definite property it didn't have before the measurement, like position. If you ask what is the position of an electron, you will get a definite answer only after measuring it. If you replace the electron by the Moon in this example, you can understand why Einstein didn't like the idea.
For Schrödinger's cat, the measurement gives the cat the property "dead" or "alive", although the cat had none of these properties before the measurement.
posted by Fillus at 10:13 AM on January 23, 2011
In essence, the act of making a measurement in Quantum Mechanics changes the system drastically. Depending on what you measure, you can give the system a definite property it didn't have before the measurement, like position. If you ask what is the position of an electron, you will get a definite answer only after measuring it. If you replace the electron by the Moon in this example, you can understand why Einstein didn't like the idea.
For Schrödinger's cat, the measurement gives the cat the property "dead" or "alive", although the cat had none of these properties before the measurement.
posted by Fillus at 10:13 AM on January 23, 2011
In essence, the act of making a measurement in Quantum Mechanics changes the system drastically.
This is actually not that hard to understand, I think. Imagine a particle you want to measure is a billiard ball, and the only way you can tell its position is to throw a bunch of other billiard balls around and wait until one hits it. It's obvious that measuring it's position changes its momentum.
Quantum mechanics isn't quite that simple, but it's not far off. Photons carry a lot of momentum relative to the particles you are measuring, and the 'smaller' the photon (that is, the more precise the measurement), the more momentum it carries.
posted by empath at 10:24 AM on January 23, 2011
This is actually not that hard to understand, I think. Imagine a particle you want to measure is a billiard ball, and the only way you can tell its position is to throw a bunch of other billiard balls around and wait until one hits it. It's obvious that measuring it's position changes its momentum.
Quantum mechanics isn't quite that simple, but it's not far off. Photons carry a lot of momentum relative to the particles you are measuring, and the 'smaller' the photon (that is, the more precise the measurement), the more momentum it carries.
posted by empath at 10:24 AM on January 23, 2011
"Imagination is the one weapon in the war against reality." - Jules de Gaultier
posted by fairmettle at 4:40 PM on January 23
Imagination is part of reality. That which is imagined, not necessarily.
posted by Decani at 10:26 AM on January 23, 2011
posted by fairmettle at 4:40 PM on January 23
Imagination is part of reality. That which is imagined, not necessarily.
posted by Decani at 10:26 AM on January 23, 2011
Reality depends on perspective; no getting around that (at least not to the extent of our knowledge so far). Also, it would be quite presumptuous to assume that humans even have the capacity to understand objective reality, if such a thing exists.
But physics and cosmology are my favorite subject to learn about. Thanks!
posted by anarch at 10:29 AM on January 23, 2011
But physics and cosmology are my favorite subject to learn about. Thanks!
posted by anarch at 10:29 AM on January 23, 2011
Reality is what you can get away with.
--R.A.W.
posted by ZenMasterThis at 10:33 AM on January 23, 2011
--R.A.W.
posted by ZenMasterThis at 10:33 AM on January 23, 2011
Toekneesan: It similarly covers the topics of relativism, quantum mechanics, and the cosmological argument. Compare and contrast.
Relativism ≠ Relativity
posted by memebake at 10:38 AM on January 23, 2011
Relativism ≠ Relativity
posted by memebake at 10:38 AM on January 23, 2011
unless you are a hardcore empiricist, "what are my experiences?", what is possible to know?" and "what is reality?" are, roughly speaking, three different questions. 'Science,' in the modern sense, is only equipped to provide answers to the first question.
the world is no more made up of particles or strings or even spacetime than it is made up of people and houses, in the sense that on the one hand, a "particle' is a way of talking about a set of measurements and on the other hand it's a mathematical model, an idea.
now, some people believe the ultimate nature of reality is ideas, that the universe is one giant computer and everything is just bits and bytes. but most physicists don't think about things that way (and built into it is the notion that ideas are just abstracted data i.e. bits and bytes where abstraction comes from intellectually...) most physicists live in the dogmatic slumber of a very naive materialism which is entirely divorced from the scientific work that they do. it's both makes it easier to talk to the public as if particles were actually out there and internally lets them off from thinking about metaphysics, which is both not very conducive to producing papers and is generally against the religion of the age which doesn't believe in metaphysical questions at all while at the same time doesn't really have any coherent approach to epistemology.
posted by ennui.bz at 10:44 AM on January 23, 2011 [2 favorites]
the world is no more made up of particles or strings or even spacetime than it is made up of people and houses, in the sense that on the one hand, a "particle' is a way of talking about a set of measurements and on the other hand it's a mathematical model, an idea.
now, some people believe the ultimate nature of reality is ideas, that the universe is one giant computer and everything is just bits and bytes. but most physicists don't think about things that way (and built into it is the notion that ideas are just abstracted data i.e. bits and bytes where abstraction comes from intellectually...) most physicists live in the dogmatic slumber of a very naive materialism which is entirely divorced from the scientific work that they do. it's both makes it easier to talk to the public as if particles were actually out there and internally lets them off from thinking about metaphysics, which is both not very conducive to producing papers and is generally against the religion of the age which doesn't believe in metaphysical questions at all while at the same time doesn't really have any coherent approach to epistemology.
posted by ennui.bz at 10:44 AM on January 23, 2011 [2 favorites]
This is actually not that hard to understand, I think. Imagine a particle you want to measure is a billiard ball, and the only way you can tell its position is to throw a bunch of other billiard balls around and wait until one hits it. It's obvious that measuring it's position changes its momentum.
This is essentially David Bohm's heresy: hidden variable theory. It's not what most quatum mechanics believe by far.
posted by ennui.bz at 10:47 AM on January 23, 2011
This is essentially David Bohm's heresy: hidden variable theory. It's not what most quatum mechanics believe by far.
posted by ennui.bz at 10:47 AM on January 23, 2011
It's not hidden variable theory, it's just a way to think about it. It's more complicated than that, as I said.
The particle basically only exists as a function that describes the probability of measuring possible positions and momenta, and measuring one or the other to an arbitrary degree of precision makes your knowledge about the other necessarily less precise, and the reason why has to do with the relationship between the wavelength and momentum of photons.
posted by empath at 10:56 AM on January 23, 2011
The particle basically only exists as a function that describes the probability of measuring possible positions and momenta, and measuring one or the other to an arbitrary degree of precision makes your knowledge about the other necessarily less precise, and the reason why has to do with the relationship between the wavelength and momentum of photons.
posted by empath at 10:56 AM on January 23, 2011
For Schrödinger's cat, the measurement gives the cat the property "dead" or "alive", although the cat had none of these properties before the measurement.
I really hate quantum mechanics talk for this reason. This explanation is pure weird solipsism. You need a HUMAN to observe the cat? Can't the cat know whether it's alive or not?
posted by curious nu at 10:57 AM on January 23, 2011 [1 favorite]
The point of schrodingers cat was to point out how ridiculous some interpretations of qm are. Somehow along the line it started being used as an example of what physicists believe. I don't think most of them think the cat is really in a superposition.
posted by empath at 11:05 AM on January 23, 2011
posted by empath at 11:05 AM on January 23, 2011
The cat would know, but it is still fogged out in a cloud of probability to everyone outside the box. It's kinda like picking out a new Pope, and knowing that someone inside the Vatican knows, but nobody outside does until they see smoke from a fireplace.
Of course, this egresses out, but instead of turtles all the way down, it's consciousnesses perceiving and collapsing the wave function all the way up. Meaning that there may need to be a consciousness outside our universe perceiving it in order for our universe to exist.
So, there ya go.
posted by Balisong at 11:05 AM on January 23, 2011
Of course, this egresses out, but instead of turtles all the way down, it's consciousnesses perceiving and collapsing the wave function all the way up. Meaning that there may need to be a consciousness outside our universe perceiving it in order for our universe to exist.
So, there ya go.
posted by Balisong at 11:05 AM on January 23, 2011
This is just speculation, but given that the holographic principle implies that all information contained within a given volume is available on the 2 dimensional surface that contains it, any observation made of the box from the outside would collapse the wave function of the whole system.
So, I think the cat would only be in a quantum superposition if the entire system were suspended in a lightless vacuum.
Given how hard it is to maintain just a couple of atoms in a superposition in experiment, I doubt we'll ever see anything like Schrodinger's Cat in the real world.
posted by empath at 11:17 AM on January 23, 2011
So, I think the cat would only be in a quantum superposition if the entire system were suspended in a lightless vacuum.
Given how hard it is to maintain just a couple of atoms in a superposition in experiment, I doubt we'll ever see anything like Schrodinger's Cat in the real world.
posted by empath at 11:17 AM on January 23, 2011
"Imagination is the one weapon in the war against reality." - Jules de Gaultier
posted by fairmettle
My imaginary foot-soldiers are packing, too.
posted by StickyCarpet at 11:47 AM on January 23, 2011
posted by fairmettle
My imaginary foot-soldiers are packing, too.
posted by StickyCarpet at 11:47 AM on January 23, 2011
Reality is what you can get away with.
--R.A.W.
posted by ZenMasterThis
Reality is that which, when you stop believing in it, doesn't go away.
--Phillip K Dick
posted by tspae at 11:50 AM on January 23, 2011 [2 favorites]
--R.A.W.
posted by ZenMasterThis
Reality is that which, when you stop believing in it, doesn't go away.
--Phillip K Dick
posted by tspae at 11:50 AM on January 23, 2011 [2 favorites]
@Curious nu:
Sorry if I can't explain well. :-) I know the formalism, but it's rather difficult to vulgarize. I was bringing up Schrödinger's cat because it is a well-known example that might talk to some people. Of course it is not easy at all to define what it means to measure a "dead" state or an "alive" state. A cat is a macroscopic object which interact in a very complicated way. I don't think you would necessarily need a human to detect if a cat is dead though. You could use an infrared camera to measure the temperature of the body for example. A better idea would be to measure the spin, which is something that we can do very well.
For your second question, it seems reasonable to assume that the cat knows if he's alive, but it is not really important here. What the theory says is that when you consider a system on which you have made no measurement, then some of its properties will not be definite. If you ask whether or not the cat knows if he's alive, you're making a measurement from inside the "black box", which is not the same problem. The measuring device and the measured system are different.
posted by Fillus at 12:11 PM on January 23, 2011
Sorry if I can't explain well. :-) I know the formalism, but it's rather difficult to vulgarize. I was bringing up Schrödinger's cat because it is a well-known example that might talk to some people. Of course it is not easy at all to define what it means to measure a "dead" state or an "alive" state. A cat is a macroscopic object which interact in a very complicated way. I don't think you would necessarily need a human to detect if a cat is dead though. You could use an infrared camera to measure the temperature of the body for example. A better idea would be to measure the spin, which is something that we can do very well.
For your second question, it seems reasonable to assume that the cat knows if he's alive, but it is not really important here. What the theory says is that when you consider a system on which you have made no measurement, then some of its properties will not be definite. If you ask whether or not the cat knows if he's alive, you're making a measurement from inside the "black box", which is not the same problem. The measuring device and the measured system are different.
posted by Fillus at 12:11 PM on January 23, 2011
Right. The cat would both be alive and know its alive, and be dead.
posted by empath at 12:14 PM on January 23, 2011
posted by empath at 12:14 PM on January 23, 2011
What constitutes measurement? Do you need a couple decimal places, or does a casual glance suffice?
If you need exacting measurements, does that mean that nothing existed (or no waveforms collapsed) before the invention of the ruler (inches or metric?) or the invention of written history?
If a casual glance will do, why does it have to be human? Can a deer who looks at the moon cause it's existence, how about moths that use the moon for their guidance systems, or the sea creatures that live on more of a lunar than solar calendar, but may never actually "see" with "eyes", but feel with gravitational and tidal forces?
posted by Balisong at 12:21 PM on January 23, 2011
If you need exacting measurements, does that mean that nothing existed (or no waveforms collapsed) before the invention of the ruler (inches or metric?) or the invention of written history?
If a casual glance will do, why does it have to be human? Can a deer who looks at the moon cause it's existence, how about moths that use the moon for their guidance systems, or the sea creatures that live on more of a lunar than solar calendar, but may never actually "see" with "eyes", but feel with gravitational and tidal forces?
posted by Balisong at 12:21 PM on January 23, 2011
Reality is that which, when you stop believing in it, doesn't go away.
--Phillip K Dick
So ∏ is real, and money isn't.
posted by Grangousier at 12:27 PM on January 23, 2011 [1 favorite]
--Phillip K Dick
So ∏ is real, and money isn't.
posted by Grangousier at 12:27 PM on January 23, 2011 [1 favorite]
From the standpoint of the cat, Schrodinger may or may not exist.
posted by Obscure Reference at 12:28 PM on January 23, 2011
posted by Obscure Reference at 12:28 PM on January 23, 2011
(I suppose there's also the possible AskMe question: "My girlfriend cheated on me. I told here I couldn't believe in her any more and she went away. Does that mean she's not real?")
posted by Grangousier at 12:30 PM on January 23, 2011 [1 favorite]
posted by Grangousier at 12:30 PM on January 23, 2011 [1 favorite]
Reality is where right wing people live, unlike me, or so they're always quick to tell me.
posted by Abiezer at 12:45 PM on January 23, 2011
posted by Abiezer at 12:45 PM on January 23, 2011
As long as you interact with the system, you make a measurement. An interaction can be of several kinds, and we usually separate them into 4: electromagnetism, the strong and weak interactions, and gravitation. It is a very general statement. Your measurement doesn't need to produce numbers or anything or interpretable. If a deer can see the Moon, it means that photons have traveled from the Sun, interacted with the surface of the Moon and bounced back towards the Earth and into the deer's eye. It is an example of electromagnetic interaction. Of course gravitational interaction can also come into play, as you mention it.
posted by Fillus at 12:46 PM on January 23, 2011
posted by Fillus at 12:46 PM on January 23, 2011
It's not what most quatum mechanics believe by far
I like the idea that people who study quantum phenomena have "quantum mechanics" as their job title.
posted by AdamCSnider at 12:58 PM on January 23, 2011
I like the idea that people who study quantum phenomena have "quantum mechanics" as their job title.
posted by AdamCSnider at 12:58 PM on January 23, 2011
I like the idea that people who study quantum phenomena have "quantum mechanics" as their job title.
My robot was feeling beside himself, so I called a quantum mechanic...
posted by device55 at 1:08 PM on January 23, 2011
My robot was feeling beside himself, so I called a quantum mechanic...
posted by device55 at 1:08 PM on January 23, 2011
What constitutes measurement?
A measurement is basically any interaction that transmits information, whether or not 'an observer' is involved.
posted by empath at 1:38 PM on January 23, 2011 [1 favorite]
A measurement is basically any interaction that transmits information, whether or not 'an observer' is involved.
posted by empath at 1:38 PM on January 23, 2011 [1 favorite]
For example, if a photon passes through a vertical polarizer, its vertical polarization has been measured, whether or not anyone was watching.
posted by empath at 1:40 PM on January 23, 2011
posted by empath at 1:40 PM on January 23, 2011
I like the idea that people who study quantum phenomena have "quantum mechanics" as their job title.
They may or may not use very, very small spanners.
posted by Grangousier at 2:00 PM on January 23, 2011
They may or may not use very, very small spanners.
posted by Grangousier at 2:00 PM on January 23, 2011
I for one am thankful for the post. The show was fascinating. The summation as I understood it - that what we perceive as "normal reality" could be a holographic-style projection from an event horizon that we experience as the "boundary" of the known Universe - was sufficiently mind-boggling for a Sunday afternoon!
posted by OneMonkeysUncle at 2:32 PM on January 23, 2011
posted by OneMonkeysUncle at 2:32 PM on January 23, 2011
At a math conference last month, there was a talk by one of the originators of Hopf algebras, which ended up being extremely important about thirty years after their initial formulation... She started the talk with (paraphrasing, as I don't have exact text):
[In heavy elderly Russian accent]: 'Today... Everything is quantum, quantum this, quantum that... Everyone is obsessed with these quantum groups now. I think it is all because of this cat. Everybody likes the cat, so now everything has to be quantum."
This is up there with my previous example of elderly Russian mathematics, when a great math-physcist explained that the inherent property of spheres is that they are round. And in fact, the four dimensional sphere is much, much rounder than the three dimensional sphere...
posted by kaibutsu at 2:40 PM on January 23, 2011 [2 favorites]
[In heavy elderly Russian accent]: 'Today... Everything is quantum, quantum this, quantum that... Everyone is obsessed with these quantum groups now. I think it is all because of this cat. Everybody likes the cat, so now everything has to be quantum."
This is up there with my previous example of elderly Russian mathematics, when a great math-physcist explained that the inherent property of spheres is that they are round. And in fact, the four dimensional sphere is much, much rounder than the three dimensional sphere...
posted by kaibutsu at 2:40 PM on January 23, 2011 [2 favorites]
unless you are a hardcore empiricist, "what are my experiences?", what is possible to know?" and "what is reality?" are, roughly speaking, three different questions. 'Science,' in the modern sense, is only equipped to provide answers to the first question.
I don't think one needs to be particularly hard-core to think that math and physics can take you somewhere beyond the first question. In fact, I would argue that the most concrete things known about the second question have come out of mathematics, and that physics has done a very good job of muddying the waters of the third question.
"What is it possible to know?"
There are piles of interesting theorems in information theory and Ramsey theory that provide solid bounds on what we can and can't know in certain situations. In communication complexity, one can find bounds on the amount of information that can be transmitted by a signal. In physics, we have the speed-of-light boundary on the transmission of information (admittedly somewhat porous, due to quantum entanglement tricks), which does a good job of limiting what can be known about another place in the universe. In computer science, the solution to the halting problem is that there is no solution: it's impossible to write a program that will tell you whether any given program will eventually halt. Statistics can be thought of as the mathematical art of answering the question 'what can we know given a pile of messy real-world information?'
But the crown jewel in this area is Godel's Theorem, which states that in any system of axioms, there will be statements which can be proven neither true nor false. In other words, mathematics can't sort the set of all statements into a 'True' pile and a 'False' pile.
Mathematics and certain areas of theoretical computer science have stated and proved numerous things about this question, and are really at the heart of modern science.
"What is reality?"
The allure and the challenge of modern physics is the degree to which observation and mathematics have combined to describe a universe that functions so radically differently from how we experience it on a day-to-day basis. I would argue that without an understanding of how reality acts, one is going to be hard pressed to confirm or refute any statement about what reality is. In particular, modern cosmology has pretty well blown, for example, medieval Christian cosmology out of the water, which in turn undermines the medieval Christian conception of the nature of reality. It's much harder to support the notion that God created the world for humans when it's now clear that the sun doesn't revolve around the earth and that the creation of the universe in fact didn't come anywhere near coinciding with the creation of humans.
It seems more and more that the way reality acts has little or nothing to do with us humans; we are ill equipped to even have a shot at understanding how the universe acts, so much so that one wonders - absent communication from an outside entity - whether we have anything resembling tools to address the question of what it's all actually about. If an answer exists, is it even something that can be placed into our meager orthographies and transmitted from one mind to another?
But maybe all this just button-holes me as a 'hard-core empiricist.' In fact, I've worked a bit with Buddhism and meditation techniques, trying to approach the question of what the world is about from a different angle. The Western philosophers of old are basically rationalists, and I think that the tools of rationality lead to an empirical understanding of the world which suggests that the philosopher's rational tools simply don't have the fuel to do their work. This leaves me with two options: (a) dedicate myself to furthering mathematics, which I kinda do, or (2) look for other ways of experiencing or understanding reality that give a different solution set than the rationalist model. In particular, one had best go looking for an experiential understanding of the world that cannot be described by a system of symbols, because mathematics is the study of symbolic manipulation, and that which I can express in symbols I can describe with mathematics. And I think that's a very valid and good thing to do, really, though perhaps obviously I can't do any real justice to the experience here, in this place that is a smattering of white symbols against a blue background.
This gets at the shortcomings of modern philosophy, and its animosity for science as well... Academic philosophy is, at its root, a game of symbolic manipulation. The math people can't deal with the philosophers because their problems are always so ill-posed as to be unanswerable, while the philosophers have a strong economic incentive to only attack ill-defined problems, lest they be forced to admit that dropping calculus probably wasn't the right reason to become a philosophy major... (Exceptions, of course, exist!)
posted by kaibutsu at 3:43 PM on January 23, 2011 [2 favorites]
I don't think one needs to be particularly hard-core to think that math and physics can take you somewhere beyond the first question. In fact, I would argue that the most concrete things known about the second question have come out of mathematics, and that physics has done a very good job of muddying the waters of the third question.
"What is it possible to know?"
There are piles of interesting theorems in information theory and Ramsey theory that provide solid bounds on what we can and can't know in certain situations. In communication complexity, one can find bounds on the amount of information that can be transmitted by a signal. In physics, we have the speed-of-light boundary on the transmission of information (admittedly somewhat porous, due to quantum entanglement tricks), which does a good job of limiting what can be known about another place in the universe. In computer science, the solution to the halting problem is that there is no solution: it's impossible to write a program that will tell you whether any given program will eventually halt. Statistics can be thought of as the mathematical art of answering the question 'what can we know given a pile of messy real-world information?'
But the crown jewel in this area is Godel's Theorem, which states that in any system of axioms, there will be statements which can be proven neither true nor false. In other words, mathematics can't sort the set of all statements into a 'True' pile and a 'False' pile.
Mathematics and certain areas of theoretical computer science have stated and proved numerous things about this question, and are really at the heart of modern science.
"What is reality?"
The allure and the challenge of modern physics is the degree to which observation and mathematics have combined to describe a universe that functions so radically differently from how we experience it on a day-to-day basis. I would argue that without an understanding of how reality acts, one is going to be hard pressed to confirm or refute any statement about what reality is. In particular, modern cosmology has pretty well blown, for example, medieval Christian cosmology out of the water, which in turn undermines the medieval Christian conception of the nature of reality. It's much harder to support the notion that God created the world for humans when it's now clear that the sun doesn't revolve around the earth and that the creation of the universe in fact didn't come anywhere near coinciding with the creation of humans.
It seems more and more that the way reality acts has little or nothing to do with us humans; we are ill equipped to even have a shot at understanding how the universe acts, so much so that one wonders - absent communication from an outside entity - whether we have anything resembling tools to address the question of what it's all actually about. If an answer exists, is it even something that can be placed into our meager orthographies and transmitted from one mind to another?
But maybe all this just button-holes me as a 'hard-core empiricist.' In fact, I've worked a bit with Buddhism and meditation techniques, trying to approach the question of what the world is about from a different angle. The Western philosophers of old are basically rationalists, and I think that the tools of rationality lead to an empirical understanding of the world which suggests that the philosopher's rational tools simply don't have the fuel to do their work. This leaves me with two options: (a) dedicate myself to furthering mathematics, which I kinda do, or (2) look for other ways of experiencing or understanding reality that give a different solution set than the rationalist model. In particular, one had best go looking for an experiential understanding of the world that cannot be described by a system of symbols, because mathematics is the study of symbolic manipulation, and that which I can express in symbols I can describe with mathematics. And I think that's a very valid and good thing to do, really, though perhaps obviously I can't do any real justice to the experience here, in this place that is a smattering of white symbols against a blue background.
This gets at the shortcomings of modern philosophy, and its animosity for science as well... Academic philosophy is, at its root, a game of symbolic manipulation. The math people can't deal with the philosophers because their problems are always so ill-posed as to be unanswerable, while the philosophers have a strong economic incentive to only attack ill-defined problems, lest they be forced to admit that dropping calculus probably wasn't the right reason to become a philosophy major... (Exceptions, of course, exist!)
posted by kaibutsu at 3:43 PM on January 23, 2011 [2 favorites]
empath: "What constitutes measurement?
A measurement is basically any interaction that transmits information, whether or not 'an observer' is involved"
This. I try so hard to convey the non-woowoo thing about "observation" and the new-age appeal of "consciousness" being necessary or special appeals to too many people and it gets distorted.
Maybe I'm wrong, but pretty much *any* interaction between two entities (2 particles) is a measurement. BUT. It's about frame of reference, so when these two particles interact, THEY "know" the information about each other (as "measured" at a given locus in spacetime) but anything outside that frame of reference still doesn't have that interaction. This is why the cat, in its frame of reference HAS collapsed into one state or the other, but to use, we can't say, so we do some handwavey stuff (even though the point of the experiment was to show how absurd it all is, not an actual state) and say it's in a superposition.
posted by symbioid at 3:56 PM on January 23, 2011
A measurement is basically any interaction that transmits information, whether or not 'an observer' is involved"
This. I try so hard to convey the non-woowoo thing about "observation" and the new-age appeal of "consciousness" being necessary or special appeals to too many people and it gets distorted.
Maybe I'm wrong, but pretty much *any* interaction between two entities (2 particles) is a measurement. BUT. It's about frame of reference, so when these two particles interact, THEY "know" the information about each other (as "measured" at a given locus in spacetime) but anything outside that frame of reference still doesn't have that interaction. This is why the cat, in its frame of reference HAS collapsed into one state or the other, but to use, we can't say, so we do some handwavey stuff (even though the point of the experiment was to show how absurd it all is, not an actual state) and say it's in a superposition.
posted by symbioid at 3:56 PM on January 23, 2011
Kaibutsu, you're misunderstanding the issue. It might be that the answer the question, "What is real?" is "Whatever physics says is real." (Many, if not most, professional philosophers believe something like this, in fact). But physics itself doesn't prove that. We couldn't employ the methodology of physics to establish that the methodology of physics is the best way to determine what is real -- we'd have to have some prior argument about why, say, conformity to predictions or utility of its laws is the best way of specifying what is real. Same again for mathematics. They don't provide the answers to what is real because they say so -- religions make the same claims, after all -- but because we have (I think) good arguments for why we should take them to be. Well, maybe not math as epistemology. That's not one I'm prepared to make.
And of course, you're offering some reasons of your own for why we should accept science or math as the answer to "What is real," but, obviously, those reasons are not scientific or mathematical reasons, but philosophical ones. And that's not far from the sort of thing philosophers do, especially philosophy of science, epistemology, and metaphysics. The insulting caricature of philosophy trades on an ignorance of what philosophers actually do, as well as what you yourself are doing, right now.
posted by Marty Marx at 6:13 PM on January 23, 2011
And of course, you're offering some reasons of your own for why we should accept science or math as the answer to "What is real," but, obviously, those reasons are not scientific or mathematical reasons, but philosophical ones. And that's not far from the sort of thing philosophers do, especially philosophy of science, epistemology, and metaphysics. The insulting caricature of philosophy trades on an ignorance of what philosophers actually do, as well as what you yourself are doing, right now.
posted by Marty Marx at 6:13 PM on January 23, 2011
*especially those in philosophy of science...
posted by Marty Marx at 6:14 PM on January 23, 2011
posted by Marty Marx at 6:14 PM on January 23, 2011
But physics itself doesn't prove that.
Philosophy doesn't either.
posted by empath at 6:49 PM on January 23, 2011
Philosophy doesn't either.
posted by empath at 6:49 PM on January 23, 2011
It would take about 300 hours or so to watch all the videos, I think. (No exaggeration)
There's a German word for the feeling of realizing that your days are numbered and you won't have time to do everything you want to do, read everything you want to read, watch everything you want to watch. The source of many mid-life crises. I don't know what that word is, but man do I feel that way reading this.
posted by zardoz at 6:51 PM on January 23, 2011 [4 favorites]
There's a German word for the feeling of realizing that your days are numbered and you won't have time to do everything you want to do, read everything you want to read, watch everything you want to watch. The source of many mid-life crises. I don't know what that word is, but man do I feel that way reading this.
posted by zardoz at 6:51 PM on January 23, 2011 [4 favorites]
I don't know, i've been watching the susskind videos once every other night or so on my laptop in bed before I go to sleep. If I get confused by something, i get more details on wikipedia. It's taken me a couple of months, but I've gone through the Quantum Mechanics and General Relativity courses already. They're not meant to make you a physicist, really, only to help you understand what it is that physicists do.
posted by empath at 7:26 PM on January 23, 2011
posted by empath at 7:26 PM on January 23, 2011
Philosophy doesn't either.
Are you saying that philosophy is inconclusive or are you saying that weighing arguments about what are and are not good reasons for believing physics is a description of all of reality is not philosophy? Only the second would have any bearing on my point.
posted by Marty Marx at 8:45 PM on January 23, 2011
Are you saying that philosophy is inconclusive or are you saying that weighing arguments about what are and are not good reasons for believing physics is a description of all of reality is not philosophy? Only the second would have any bearing on my point.
posted by Marty Marx at 8:45 PM on January 23, 2011
most physicists live in the dogmatic slumber of a very naive materialism which is entirely divorced from the scientific work that they do.
In my experience this is not really true for theorists, nor for cosmology or HE people. It is true for the plasma, condensed matter, etc. physicists though, though I think that if you really probed the issue most of them could be convinced of an anti-realist view.
posted by atrazine at 9:14 PM on January 23, 2011
In my experience this is not really true for theorists, nor for cosmology or HE people. It is true for the plasma, condensed matter, etc. physicists though, though I think that if you really probed the issue most of them could be convinced of an anti-realist view.
posted by atrazine at 9:14 PM on January 23, 2011
The cat will know whether it is alive or dead, and it won't much care how anyone or anything else perceives it.
posted by stargell at 9:24 PM on January 23, 2011 [2 favorites]
posted by stargell at 9:24 PM on January 23, 2011 [2 favorites]
Are you saying that philosophy is inconclusive or are you saying that weighing arguments about what are and are not good reasons for believing physics is a description of all of reality is not philosophy?
You said that science can't prove that it's methodology is the best way to determine what is real. I'm saying that philosophy can't prove it either. It doesn't add anything to science.
posted by empath at 10:30 PM on January 23, 2011
You said that science can't prove that it's methodology is the best way to determine what is real. I'm saying that philosophy can't prove it either. It doesn't add anything to science.
posted by empath at 10:30 PM on January 23, 2011
The cat will know whether it is alive or dead...
I will give you half marks for that statement.
posted by weapons-grade pandemonium at 11:08 PM on January 23, 2011
I will give you half marks for that statement.
posted by weapons-grade pandemonium at 11:08 PM on January 23, 2011
you're misunderstanding the issue. It might be that the answer the question, "What is real?" is "Whatever physics says is real." [...] But physics itself doesn't prove that.
I'm not arguing that at all. I'm arguing that physics - which concerns itself with the collection and manipulation of empirical data, and the manipulation of symbols to form theories - is every bit and no more constrained as academic philosophy in its ability to describe what reality is. Academic philosophers ply their trade through the manipulation of symbols, and thus cannot expect to get any farther than people whose trade is the manipulation of symbols and the interpretation of data, unless by miracle of specialization.
The other specialists in symbol manipulation are mathematicians, who seem, at least to me, to be producing knowledge at a rate dwarfing that of the philosophy community, and have actively fed the understanding of the physicists for the past couple centuries, in spite of not committing to any notion of 'what is real.' Academic philosophy, on the other hand, has largely failed to produce meaningful results.
posted by kaibutsu at 2:02 AM on January 24, 2011
I'm not arguing that at all. I'm arguing that physics - which concerns itself with the collection and manipulation of empirical data, and the manipulation of symbols to form theories - is every bit and no more constrained as academic philosophy in its ability to describe what reality is. Academic philosophers ply their trade through the manipulation of symbols, and thus cannot expect to get any farther than people whose trade is the manipulation of symbols and the interpretation of data, unless by miracle of specialization.
The other specialists in symbol manipulation are mathematicians, who seem, at least to me, to be producing knowledge at a rate dwarfing that of the philosophy community, and have actively fed the understanding of the physicists for the past couple centuries, in spite of not committing to any notion of 'what is real.' Academic philosophy, on the other hand, has largely failed to produce meaningful results.
posted by kaibutsu at 2:02 AM on January 24, 2011
I recommend reading On Physics and Philosophy by Bernard d'Espagnant. One of the main themes of the book is the concept of mind independent reality, what the author calls "veiled reality". Also worth a read is the still relevant classic, Physics and Philosophy, by Sir James Jeans.
posted by AElfwine Evenstar at 5:45 AM on January 24, 2011
posted by AElfwine Evenstar at 5:45 AM on January 24, 2011
Quantum Theory : A Pointer To An Independent Reality
How to spell out the epistemic conception of quantum states
Are there alternatives to our present theories of physical reality?
There also seems to be a group of physicists who are arguing for emphasis on the primacy of consciousness to the construction and/or creation of reality.
Quantum Non-Locality and Universe
Can we debug the Universe?
For more examples of this see the work of Roger Penrose a la Orchestrated Objective Reduction and the book Quantum Enigma: Physics Encounters Consciousness by Rosenblum and Kuttner. These are not majority viewpoints to be sure, but interesting none the less.
Another interesting concept is that of Quantum Darwinism; which is basically a theory explaining the emergence of the macroscopic world from the quantum scale through a process of natural selection.
Quantum Darwinism and the Nature of Reality
Quantum Darwinism
Natural selection could explain one of the biggest conundrums of quantum mechanics: The emergence of objective reality.
Universal Darwinism
Quantum Darwinism
The concept of Quantum Darwinism follows David Deutsch's claim in The Fabric of Reality that any GUT will inevitably synthesize the theory of evolution.
posted by AElfwine Evenstar at 6:57 AM on January 24, 2011 [1 favorite]
How to spell out the epistemic conception of quantum states
Are there alternatives to our present theories of physical reality?
There also seems to be a group of physicists who are arguing for emphasis on the primacy of consciousness to the construction and/or creation of reality.
Quantum Non-Locality and Universe
Can we debug the Universe?
For more examples of this see the work of Roger Penrose a la Orchestrated Objective Reduction and the book Quantum Enigma: Physics Encounters Consciousness by Rosenblum and Kuttner. These are not majority viewpoints to be sure, but interesting none the less.
Another interesting concept is that of Quantum Darwinism; which is basically a theory explaining the emergence of the macroscopic world from the quantum scale through a process of natural selection.
Quantum Darwinism and the Nature of Reality
Quantum Darwinism
Natural selection could explain one of the biggest conundrums of quantum mechanics: The emergence of objective reality.
Universal Darwinism
Quantum Darwinism
The concept of Quantum Darwinism follows David Deutsch's claim in The Fabric of Reality that any GUT will inevitably synthesize the theory of evolution.
posted by AElfwine Evenstar at 6:57 AM on January 24, 2011 [1 favorite]
there's also roger penrose's road to reality :P
oh and Quantum Entanglement Could Stretch Across Time...
yea, i'm not sure information (or mind/consciousness) can be separated from objective physical reality. altho atoms and bits make useful distinctions, like alive or dead, information must still be encoded on some substrate; there is no mind without the brain, as it were. as such, you could say that it's all information and take an information theoretic view of physics, which some have tried to take in the direction of uni/multiverse as computer, like it's just performing (continuous or discrete?) calculations -- iterated reality. physics then kind of literally becomes epistemology and 'what can we know' defines the boundaries of our existence after all.
posted by kliuless at 7:42 AM on January 24, 2011 [1 favorite]
oh and Quantum Entanglement Could Stretch Across Time...
yea, i'm not sure information (or mind/consciousness) can be separated from objective physical reality. altho atoms and bits make useful distinctions, like alive or dead, information must still be encoded on some substrate; there is no mind without the brain, as it were. as such, you could say that it's all information and take an information theoretic view of physics, which some have tried to take in the direction of uni/multiverse as computer, like it's just performing (continuous or discrete?) calculations -- iterated reality. physics then kind of literally becomes epistemology and 'what can we know' defines the boundaries of our existence after all.
posted by kliuless at 7:42 AM on January 24, 2011 [1 favorite]
there is no mind without the brain
I would agree with you to a point, but I am not sold on this. The work of Gregory Bateson (Steps to an Ecology of Mind for example) takes a cybernetic approach which posits that mind exists outside of individuals and that mind can only be properly understood in the context of a cybernetic system which includes the individual, culture, and the surrounding ecosystem. According to Bateson consciousness is the connector which unites these three parts(individual, culture, and ecosystem) into a complete cybernetic system or mind. This is a decidedly Durkheimian approach to the mind-body problem. To clarify I am not sure I buy this either but am just throwing it out there to play devil's advocate.
Another interesting question is can superorganisms be said to have mind? Can we analyze evolution from this perspective? Following from the work of Elderidge and others we can begin to conceptualize populations and regional biotal systems as individual entities propagating through time. Can these entities be said to have mind? I would argue that according to Bateson's cybernetic model they can in fact be said to exhibit the properties of mind. Again I am not sure this is the answer but it is an intriguing conjecture.
posted by AElfwine Evenstar at 8:17 AM on January 24, 2011 [1 favorite]
I would agree with you to a point, but I am not sold on this. The work of Gregory Bateson (Steps to an Ecology of Mind for example) takes a cybernetic approach which posits that mind exists outside of individuals and that mind can only be properly understood in the context of a cybernetic system which includes the individual, culture, and the surrounding ecosystem. According to Bateson consciousness is the connector which unites these three parts(individual, culture, and ecosystem) into a complete cybernetic system or mind. This is a decidedly Durkheimian approach to the mind-body problem. To clarify I am not sure I buy this either but am just throwing it out there to play devil's advocate.
Another interesting question is can superorganisms be said to have mind? Can we analyze evolution from this perspective? Following from the work of Elderidge and others we can begin to conceptualize populations and regional biotal systems as individual entities propagating through time. Can these entities be said to have mind? I would argue that according to Bateson's cybernetic model they can in fact be said to exhibit the properties of mind. Again I am not sure this is the answer but it is an intriguing conjecture.
posted by AElfwine Evenstar at 8:17 AM on January 24, 2011 [1 favorite]
there's also roger penrose's road to reality
Hey thanks, I've read The Emporer's New Mind and Shadows of the Mind but have somehow missed this.
posted by AElfwine Evenstar at 8:21 AM on January 24, 2011
Hey thanks, I've read The Emporer's New Mind and Shadows of the Mind but have somehow missed this.
posted by AElfwine Evenstar at 8:21 AM on January 24, 2011
that's like saying the earth has a biospheric consciousness or whatever, or that since we have consciousness the whole universe does; we're the universe contemplating itself (into existence ;) or something! does the universe need an observer at the end of time?
i dunno... maybe i guess? i mean, it appears pretty clear that since we build telescopes and observe the cosmic microwave background and stuff that external stimuli from the outside world is internalized by changing our brain structures somehow, so we are to some degree 'a part of a larger whole' -- a cybernetic complex adaptive system if you will -- but whether that's trivial or profound i'll leave as an exercise for the reader :P
to take the whole problem of consciousness out of it tho, i was just trying to make the point that like a rock on some level -- perhaps at its most fundamental -- can be seen as a collection of information, embedding a certain configuration of data (in relation to its environment). moreover, limited information if not conserved (with access to the multiverse; deutsch's supposition?) may be how probabilities arise, essentially from rounding errors, which seems intuitive to me...
kind of like if it's all math with "primes as atoms" then to an extent reality is irreducible!
posted by kliuless at 11:42 AM on January 24, 2011
i dunno... maybe i guess? i mean, it appears pretty clear that since we build telescopes and observe the cosmic microwave background and stuff that external stimuli from the outside world is internalized by changing our brain structures somehow, so we are to some degree 'a part of a larger whole' -- a cybernetic complex adaptive system if you will -- but whether that's trivial or profound i'll leave as an exercise for the reader :P
to take the whole problem of consciousness out of it tho, i was just trying to make the point that like a rock on some level -- perhaps at its most fundamental -- can be seen as a collection of information, embedding a certain configuration of data (in relation to its environment). moreover, limited information if not conserved (with access to the multiverse; deutsch's supposition?) may be how probabilities arise, essentially from rounding errors, which seems intuitive to me...
kind of like if it's all math with "primes as atoms" then to an extent reality is irreducible!
posted by kliuless at 11:42 AM on January 24, 2011
I definitely think there's no mind without a brain, but I don't think the brain is the whole story. It's also the patterns that the brain holds, and those patterns doesn't necessarily need to be entirely in the brain.
posted by empath at 12:01 PM on January 24, 2011
posted by empath at 12:01 PM on January 24, 2011
The summation as I understood it - that what we perceive as "normal reality" could be a holographic-style projection from an event horizon that we experience as the "boundary" of the known Universe - was sufficiently mind-boggling for a Sunday afternoon!
My wife and I watched this program last night, and really enjoyed it ourselves. I was particularly tickled when the off-screen interviewer said to Susskind (I'm paraphrasing), "I think I'm getting it," and he responded, "no you're not, no one gets this."
---
And on a somber note, the Tevatron at Fermilab (featured in the first half of the Horizon program) will be shut down in September.
posted by BobbyVan at 2:28 PM on January 24, 2011
My wife and I watched this program last night, and really enjoyed it ourselves. I was particularly tickled when the off-screen interviewer said to Susskind (I'm paraphrasing), "I think I'm getting it," and he responded, "no you're not, no one gets this."
---
And on a somber note, the Tevatron at Fermilab (featured in the first half of the Horizon program) will be shut down in September.
posted by BobbyVan at 2:28 PM on January 24, 2011
And on a somber note, the Tevatron at Fermilab (featured in the first half of the Horizon program) will be shut down in September.
God that's a depressing article. :(
Empath, I'm at work so I don't have time to respond in depth but as I said I don't really know where I stand. Bateson's argument would be that without the brain there is no consciousness, and that consciousness is but one of the many ways to gain information about "reality". Mind can exist independent of consciousness functioning in a cybernetic system.
posted by AElfwine Evenstar at 3:00 PM on January 24, 2011
God that's a depressing article. :(
Empath, I'm at work so I don't have time to respond in depth but as I said I don't really know where I stand. Bateson's argument would be that without the brain there is no consciousness, and that consciousness is but one of the many ways to gain information about "reality". Mind can exist independent of consciousness functioning in a cybernetic system.
posted by AElfwine Evenstar at 3:00 PM on January 24, 2011
that's like saying the earth has a biospheric consciousness or whatever
Haven't you heard? Panpsychism is the next big thing. All the cool kids are talking about it. :)
posted by AElfwine Evenstar at 3:05 PM on January 24, 2011
Haven't you heard? Panpsychism is the next big thing. All the cool kids are talking about it. :)
posted by AElfwine Evenstar at 3:05 PM on January 24, 2011
"There's a German word for the feeling of realizing that your days are numbered and you won't have time to do everything you want to do, read everything you want to read, watch everything you want to watch."
Torschlusspanik
posted by Eideteker at 5:17 AM on January 26, 2011 [1 favorite]
Torschlusspanik
posted by Eideteker at 5:17 AM on January 26, 2011 [1 favorite]
I once went into a bookshop and asked the assistants to recommend a book that would change my world. They wanted to know more about me and were initially perplexed when I said that the only information they should base their suggestions on was anything they inferred from the fact that I had asked the question and my appearance (unremarkably dressed middle-aged man).
Alongside some more obvious suggestions (The Alchemist, Jonathan Livingstone Seagull and the like) someone pointed me at David Deutsch's book 'The Fabric of Reality'. As a non-physicist it absolutely did change my view of the world, which was very good value for £8.99.
FWIW I heartily recommend playing this game in bookshops. The assistants loved it. As people who are mostly passionate about books I think it made a welcome change from signposting the latest ghost written celebrity autobiography or TV cookery show spin off.
posted by Neil Hunt at 10:46 PM on February 17, 2011
Alongside some more obvious suggestions (The Alchemist, Jonathan Livingstone Seagull and the like) someone pointed me at David Deutsch's book 'The Fabric of Reality'. As a non-physicist it absolutely did change my view of the world, which was very good value for £8.99.
FWIW I heartily recommend playing this game in bookshops. The assistants loved it. As people who are mostly passionate about books I think it made a welcome change from signposting the latest ghost written celebrity autobiography or TV cookery show spin off.
posted by Neil Hunt at 10:46 PM on February 17, 2011
« Older The Purpose and Techniques of Calligraphy | Saul Bass Newer »
This thread has been archived and is closed to new comments
posted by weapons-grade pandemonium at 8:35 AM on January 23, 2011 [2 favorites]