Space Cadet Will Hutton is sadly misinformed.

[UndercoverElephant]

I shall allow you the last word if you would care for it.

[JavaScriptDonkey]

In other words when you proclaimed to the board that "the observer problems in QM are all down to information entropy" you were basing that claim on neither the maths behind QM, nor any knowledge of the metaphysical implications of the interpretations. i.e. you don't know what you are talking about.

I go away for a few days and this is what I come back to.

Let me try to keep this simple for the BA's at the back.

In order to observe something information needs to flow. Usually this is light in the form of photons bouncing into your eyes at varying wavelengths and all is happy.

In the quantum world when you are dealing with sub atomic particles there are no conveniently sized particles to transmit the information to you and any that could would interact with the thing that you are trying to study. You have to infer. However this means that you cannot precisely know everything about the particle with absolute certainty as observing the thing changes it.

No philosophy, no consciousness, no subjective universe, just long established information theory with a dash of entropy.

If you had at least a feel for the subject you would know that all Shrodinger's cat was meant to show was that quantum theories such as entanglement can't be extrapolated up to macro masses. It only applies to subatomic particles. This of course leads on to musing about the nature of the interaction of mass with space-time and hence through ideas of quantum gravity and maybe to a new view on the formation of the mass in our universe.

Or you could write a paper on how quantum waves collapse on contact with a consciousness.

[RogueMale]

If you had at least a feel for the subject you would know that all Shrodinger's cat was meant to show was that quantum theories such as entanglement can't be extrapolated up to macro masses. It only applies to subatomic particles. This of course leads on to musing about the nature of the interaction of mass with space-time and hence through ideas of quantum gravity and maybe to a new view on the formation of the mass in our universe.

Or you could write a paper on how quantum waves collapse on contact with a consciousness.

My guess is that when you open the box and see the cat alive, the universe splits in in two, and your consciousness finds itself in the cat-alive universe, instead of the cat-dead universe. This actually makes free will possible: all possible future universes are predetermined, but your consciousness gets to choose which one it stays in. However, how you could have the information necessary to make the decision you want is unclear to me. It's also entirely possible that I'm the only conscious entity in the universe I find myself in, and everyone else is a zombie.

Or should I just shut up and calculate?

[Ludwig]

In order to observe something information needs to flow.

Usually this is light in the form of photons bouncing into your eyes at varying wavelengths are all is happy.

In what sense is this "information"? Sounds to me like basic physical processes.

What's "information" without something to interpret it?

In the quantum world when you are dealing with sub atomic particles there are no conveniently sized particles to transmit the information to you and any that could would interact with the thing that you are trying to study. You have to infer. However this means that you cannot precisely know everything about the particle with absolute certainty as observing the thing changes it.

One of the numerous books I've read about QM - all of them written by physicists, before you ask - said explicitly that the Uncertainty Principle is a fundamental property of nature, and NOT simply to do with the limitations of our measuring techniques.

The double slit experiment shows that. Try to find which of 2 holes an electron went through, and the interference pattern disappears, making the electron look like an particle. Leave the measurement till the electron hits the screen, and the wave pattern shows. The wave pattern cannot be explained by any "macro" interpretation of the electrons as particles.

It's not simply a problem of us disturbing the billiard balls of matter with our observation equipment. Unobserved, matter is nothing like billiard balls, it is waves.

I can't remember which book this was, it might have been "Quantum Reality" by Nick Herbert, or "The Cosmic Code" by Heinz Pagels.

No philosophy, no consciousness, no subjective universe, just long established information theory with a dash of entropy.

Pseudo-intellectual twaddle.

Information theory was invented for purposes of engineering, not investigation into physics - which hasn't stopped second-rate physicists from trying to make out that it "explains" anything. Shannon himself explicitly excluded the idea of meaning from his definition of "information" - he was a mathematician-cum-technologist, and was interested in communication algorithms, not physics.

If you had at least a feel for the subject you would know that all Shrodinger's cat was meant to show was that quantum theories such as entanglement can't be extrapolated up to macro masses. It only applies to subatomic particles.

Schroedinger wasn't "showing" anything, he was pointing up the fundamental paradox of quantum mechanics. If that cat is definitely alive or definitely dead, at what point does "quantum weirdness" stop and "macro normality" begin?

I am acquainted with a Cambridge University physicist who assures me that this ontological problem has not been resolved.

(And incidentally, Schroedinger explicitly espoused a "mystical" view of quantum physics in later life - he was cagier early on in his career.)

[UndercoverElephant]

If you had at least a feel for the subject you would know that all Shrodinger's cat was meant to show was that quantum theories such as entanglement can't be extrapolated up to macro masses. It only applies to subatomic particles. This of course leads on to musing about the nature of the interaction of mass with space-time and hence through ideas of quantum gravity and maybe to a new view on the formation of the mass in our universe.

Or you could write a paper on how quantum waves collapse on contact with a consciousness.

My guess is that when you open the box and see the cat alive, the universe splits in in two, and your consciousness finds itself in the cat-alive universe, instead of the cat-dead universe. This actually makes free will possible: all possible future universes are predetermined, but your consciousness gets to choose which one it stays in. However, how you could have the information necessary to make the decision you want is unclear to me. It's also entirely possible that I'm the only conscious entity in the universe I find myself in, and everyone else is a zombie.

Or should I just shut up and calculate?

[Ludwig]

My guess is that when you open the box and see the cat alive, the universe splits in in two, and your consciousness finds itself in the cat-alive universe, instead of the cat-dead universe. This actually makes free will possible: all possible future universes are predetermined, but your consciousness gets to choose which one it stays in.

I have a problem with this idea. I find it messy. How does your consciousness "choose" which universe to stay in? Where is the free will in this?

I don't really like the multiverse idea in general. It's not for me to say that it's wrong, but the idea of an infinitely bifurcating universe feels awkward to me - at every single instant the universe is "expanding" following a mind-bogglingly enormouse exponential function? Like the economic idea of endless growth, it doesn't address the issue of where it all ends. I tend not to believe that anything goes on infinitely, but rather than things' ends are held in their beginnings - that everything loops back on itself. Somehow. I'm still thinking about all this. But I think retrocausation might have something to do with it.

I'm not saying you're wrong, just that in the absence of evidence, the idea doesn't appeal to me.

[Ludwig]

[EDIT] Do you agree with Ludwig's concept of phenomena?

Yes.

Phenomena are the world as we percieve it, to be contrasted with noumena, which are the world as it is in itself. In what category should we put stuff we percieve but aren't really aware of? Not noumena, obviously.

As an aside, I'm inclined to the view that the distinction between noumena and phenomena might be artificial: that there is no "world in itself", that everything is somehow linked to perception.

[UndercoverElephant]

[EDIT] Do you agree with Ludwig's concept of phenomena?

Yes.

Phenomena are the world as we percieve it, to be contrasted with noumena, which are the world as it is in itself. In what category should we put stuff we percieve but aren't really aware of? Not noumena, obviously.

As an aside, I'm inclined to the view that the distinction between noumena and phenomena might be artificial: that there is no "world in itself", that everything is somehow linked to perception.

This would be following Schopenhauer and Hegel's re-interpretation of Kant. Both of the questioned the need for any "world in itself". This position is normally known as "objective idealism."

[caspian]

Anyone who believes that the laws of physics are mere social conventions is invited to try transgressing those conventions from the windows of my apartment. (I live on the twenty-first floor.)

- Alan Sokal, Transgressing the Boundaries: Towards a Transformative Hermeneutics of Quantum Gravity (Social Text #46/47)

[UndercoverElephant]

Anyone who believes that the laws of physics are mere social conventions is invited to try transgressing those conventions from the windows of my apartment. (I live on the twenty-first floor.)

- Alan Sokal, Transgressing the Boundaries: Towards a Transformative Hermeneutics of Quantum Gravity (Social Text #46/47)

Nobody is suggesting that.

[Ludwig]

Anyone who believes that the laws of physics are mere social conventions is invited to try transgressing those conventions from the windows of my apartment. (I live on the twenty-first floor.)

- Alan Sokal, Transgressing the Boundaries: Towards a Transformative Hermeneutics of Quantum Gravity (Social Text #46/47)

He would do well to engage in honest intellectual debate, rather using disingenuous straw man tactics to try to make out that his opponents are not worth arguing with.

Where has anyone in this discussion talked of the laws of physics being "social conventions"?

I don't disagree with the most rigid materialist about the laws of physics. I just disagree with his interpretation of them.

[Ludwig]

Yes.

Phenomena are the world as we percieve it, to be contrasted with noumena, which are the world as it is in itself. In what category should we put stuff we percieve but aren't really aware of? Not noumena, obviously.

As an aside, I'm inclined to the view that the distinction between noumena and phenomena might be artificial: that there is no "world in itself", that everything is somehow linked to perception.

This would be following Schopenhauer and Hegel's re-interpretation of Kant. Both of the questioned the need for any "world in itself". This position is normally known as "objective idealism."

Inneresting.

[JavaScriptDonkey]

[SNIP]
wrote lots of words about philosophy
[SNIP]

You didn't expand on how you think we can know anything about sub atomic particles with out the means to measure them or why changing a thing by the act of detecting doesn't cause you any problems.

It was explained to me thus;

Think of a dark room. In the room there is a black box process that consists of a small bulb connected to a light sensitive switch. Whenever the room is dark, the bulb is off. Whenever the room is light, the bulb is on. You have a torch. Discuss why the bulb only lights whenever you look for it. How does it know you're looking?

There are of course other theories. You can pretend that subatomic particles are aware of our humanity and behave specially just for us as distinct from any other observer in the Universe. Such as another sub atomic particle. Or you could postulate that multiple universes continually splinter off as every wave collapses. Or maybe there is only one wave and it never collapses.

[Ludwig]

As an aside, I'm inclined to the view that the distinction between noumena and phenomena might be artificial: that there is no "world in itself", that everything is somehow linked to perception.

This would be following Schopenhauer and Hegel's re-interpretation of Kant. Both of the questioned the need for any "world in itself". This position is normally known as "objective idealism."

One way of putting it might be that the "world in itself" does exist, but only in the sense of potentialities, or probability waves - Bohm's "implicate order", or the "manifesting world" of the Tewa Indians. Phenomena then would represent the collapse of the wave function (the "explicate order" or the "manifest world").

[Ludwig]

[SNIP]
wrote lots of words about philosophy
[SNIP]

If you'd actually read my post, you'd have noticed that all my sources were physicists, not philosophers.

You didn't expand on how you think we can know anything about sub atomic particles with out the means to measure them

Where did I say I think that? I think the opposite.

or why changing a thing by the act of detecting doesn't cause you any problems.

Because what is being changed is not a single, simple characteristic of that "thing", but its very nature.

The "materialist" interpretation of QM is that every particle has a definite position and a definite momentum, and the only problem is that we can't find out both at the same time. Einstein thought this, but the maths and, later, experimental results, proved him wrong.

The double slit experiment shows that this interpretation cannot be true. When we don't look to see which slit a particle goes through, it goes through both. It shows up on the detector in a position it can't possibly have arrived at if it had definitely gone through one slit or the other.

I'm guessing that both you and AndySir have been through the education system since the idea of listening to, and assessing, other points of view dispassionately was dropped, in favour of the idea that all opinions are a priori valid, and that the sign of a good mind is the ability to wilfully misinterpret others' statements in such a way that you can "prove" them wrong. That may be a good way of boosting young people's self-esteem, but it guarantees they will never learn anything.