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markporter
Fire over Oxford
Date Joined Oct 2003
Total Posts : 263
| Posted 11/13/2003 12:31 AM (GMT -6) |   | | Well, what do you guys think of it? (there's a good outline at http://plato.stanford.edu/entries/qm-bohm/) are there elements which are counter-intuitive, or is it more logical than standard QM? | | Back to Top | | |
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Alan Rhoda
Registered Member
Date Joined May 2002
Total Posts : 680
| Posted 11/13/2003 2:12 PM (GMT -6) | | Very interesting, Mark. I'm no physicist so I can't say with any confidence whether Bohmian mechanics is better than standard Copenhagen QM, but if it does avoid the quantum measurement problem (I can't really explain the problem, I just know that theorists who specializes in this stuff regard it as a problem), that's got to be a plus in its favor. As far as open theism goes, I don't think it matters much whether Bohm or Bohr is right because the relevant indeterminacy concerns human freedom, not quantum-level events.
Alan | | Back to Top | | |
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markporter
Fire over Oxford
Date Joined Oct 2003
Total Posts : 263
| Posted 11/14/2003 2:03 AM (GMT -6) | | | surely it does matter to a certain degree, firstly if we are assuming that a possible way of mind-body interactions is via quantum indeterminacy, and also QM is often used to prove that such a thing as indeterminacy makes sense in the first place. | | Back to Top | | |
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Laika
Registered Member
Date Joined Mar 2003
Total Posts : 2433
| Posted 11/14/2003 3:06 AM (GMT -6) | | quote:
Originally posted by markporter
surely it does matter to a certain degree, firstly if we are assuming that a possible way of mind-body interactions is via quantum indeterminacy, and also QM is often used to prove that such a thing as indeterminacy makes sense in the first place.
from http://www.intercom.net/~tarababe/MtRush.html
quote:
John Stewart Bell, who elaborated the concerns of Einstein and Schrödinger more clearly than anyone, via his championing the cause of hidden variables, and in particular de Broglie and Bohm's hidden variables.
"By the time this was fully clarified by Bohm in 1952, few theoretical physicists wanted to hear about it. The orthodox line seemed fully justified by practical success. Even now the de Broglie-Bohm picture is generally ignored, and not taught to students. I think this is a great loss. For that picture exercises the mind in a very salutary way."
"Why is the pilot wave picture [de Broglie and Bohm's hidden variables] ignored in text books? Should it not be taught, not as the only way, but as an antidote to the prevailing complacency? To show that vagueness, subjectivity, and indeterminism are not forced upon us by experimental facts, but by deliberate theoretical choice?"
inside you the time moves and she don't fade
the ghost in you she don't fade | | Back to Top | | |
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Alan Rhoda
Registered Member
Date Joined May 2002
Total Posts : 680
| Posted 11/14/2003 7:37 AM (GMT -6) | | Mark: Surely it does matter to a certain degree, firstly if we are assuming that a possible way of mind-body interactions is via quantum indeterminacy.
Alan: You're right that Bohmian mechanics would close down one way of bringing mind-body interactions into harmony with physics. If that were the only, or the most plausible, way of doing so, then that might create problems for open theism. But I do not see that it is the only, or the most plausible, way. In fact, posing the issue of mind-body interaction in this context seems to presuppose a Cartesian-like mind-body dualism that is problematic for Christianity. The picture seems to be that we have this "mind" over here externally related to a "body" over there, and somehow effecting changes in that body by somehow acting upon it. But the Christian doctrine of the resurrection of the body suggests that our bodies and souls are more than just externally related to each other. It seems to me that we can circumvent the mind-body interaction problem by recognizing that human beings are psycho-physical unities (along the lines of Aquinas' hylomorphic dualism, as J.P. Moreland argues in Body and Soul) and that we are capable of agent causation. In this case it is not the soul or mind acting upon the body, but rather an embodied agent acting.
Mark: Also QM is often used to prove that such a thing as indeterminacy makes sense in the first place.
Alan: True, but to show that indeterminacy makes sense it suffices that the Copenhagen Interpretation is possible. That can be the case even if it is in fact false.
Which interpretation of QM is right? I don't pretend to know. But I think open theists need to be careful in looking to physics to find fundamental support for their worldview. OT does not ultimately stand or fall on physics, but on metaphysics and exegesis.
Regards,
Alan
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Magneton
Registered Member
Date Joined Aug 2001
Total Posts : 132
| Posted 11/16/2003 1:03 PM (GMT -6) | | Mark, thanks for the article – it’s a good overview of Bohm’s thinking, which is difficult to get a handle on. The article is especially good on the issue of nonlocality as it relates to hidden variables and quantum theory. Nonlocality, as the author notes, is not only a restriction on the nature of hidden variables, but is a necessary feature of QM.
On the measurement problem, I like the quote by Bell:quote:
A final moral concerns terminology. Why did such serious people take so seriously axioms which now seem so arbitrary? I suspect that they were misled by the pernicious misuse of the word ‘measurement’ in contemporary theory. This word very strongly suggests the ascertaining of some preexisting property of some thing, any instrument involved playing a purely passive role. Quantum experiments are just not like that, as we learned especially from Bohr. The results have to be regarded as the joint product of ‘system’ and ‘apparatus,’ the complete experimental set-up. But the misuse of the word ‘measurement’ makes it easy to forget this and then to expect that the ‘results of measurements’ should obey some simple logic in which the apparatus is not mentioned. The resulting difficulties soon show that any such logic is not ordinary logic. It is my impression that the whole vast subject of ‘Quantum Logic’ has arisen in this way from the misuse of a word. I am convinced that the word ‘measurement’ has now been so abused that the field would be significantly advanced by banning its use altogether, in favour for example of the word ‘experiment.’
The measurement problem arises when we fail to recognize the inseparability of ‘system’ and ‘apparatus’ or of ‘subject’ and ‘object.’
In his later works, Bohm emphasized that his causal interpretation of QM did not necessarily imply determinism:quote:
Although the interpretation is termed causal, this should not be taken as implying a form of complete determinism. Indeed it will be shown that this interpretation opens the door for the creative operation of underlying, and yet subtler, levels of reality.
- David Bohm and F. David Peat, Science, Order, and Creativity, p. 88
Over the years his name for the view evolved from “hidden variables” to “causal interpretation” to “ontological interpretation.” He seems to dance around the issue of determinism, with multiple levels of reality that can be alternately deterministic or indeterministic, based on the connectedness and organization of the cosmos at many levels. At the deepest level, however, encompassing all of reality (a kind of state function of the universe), the deterministic aspects of his view seem inescapable, but he views this as a trivial case. (I think it was in The Undivided Universe where he said that.)
Alan, I agree that the OV doesn’t rise or fall on this issue – that human free will is the major issue. I do like the idea, however, that openness preceded sentient creatures: that God created a universe with the “freedom” of self-adaptation to achieve higher-valued states than would be possible in a “blueprint” universe.
Magneton
“I think that I can safely say that nobody understands quantum mechanics.” Richard Feynman
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Iconoclast
Registered Member
Date Joined Oct 2001
Total Posts : 1227
| Posted 11/27/2003 6:29 AM (GMT -6) | | Bohm Rocks!
Great thread Mark. Great stuff Magneton, Laika and Alan.
I think Bohm's interpretation of QM makes WAY more sense than the Copenhagen interpretation. I think that the Copenhagen interpretation comes about because us humans continue to confuse the map with the territory. Bohm simply refuses to do this and thus abducts a possible ontological interpretation of QM that not only makes intuitive sense but also allows us to continue to explore deeper levels of "reality" or rather deeper and more subtle maps of the territory that we find ourselves within.
As far as whether Bohmian mechanics implies determinism or not check out this quote from "The Undivided Universe: An Ontological Interpretation of Quantum Theory" by Bohm and Hiley:
>>>>>
The original papers in which the ideas were first proposed were entitled "An Interpretation in Terms of Hidden Variables" and later they were referred to as a "Causal Interpretation". However, we now feel that these terms are too restrictive. First of all, our variables are not actually hidden. For example, we introduce the concept that the electron is a particle with a well-defined position and momentum that is, however, profoundly affected by a wave that always accompanies it. Far from being hidden, this particle is generally what is most directly manifested in an observation. Theonly point is that its properties cannot be observed with complete precision (within the limits set by the uncertainty principle). Nor is this sort of theory necessarily causal. For, as shown in chapter 9, we can also have a stochastic version of our ontological interpretation. The question of determinism is therefore a secondary on, while the primary question is whether we can have an adequate conception of the reality of a quantum system, be this causal or be it stochastic or be it of any other nature.
In chapter 14 section 14.2 we explain our general attitude to determinism in more detail, but the main point that is relevant here is that we regard all theories as approximations with limited domains of validity. Some theories may be more nearly deterministic, while others are less so. The way is open for the constant discovery of new theories, but ultimately these must be related coherently. However, there is no reason to suppose that physical theory is steadily approaching some final truth. It is always open (as has indeed generally been the case) that new theories will have a qualitatively different content within shich the older theories may be seen to fit together, perhaps in some approximate way. Since there is no final theory, it cannot be said that the universe is either ultimately deterministic or ultimately indeterministic. Therefore we cannot from physical theories alone draw any conclusions, for example, about the ultimate limits of human freedom.
<<<<<<<<<
I am confident that the Copenhagen interpretation will ultimately be overthrown as a useful understanding of QM. Why? Three reasons:
1. It fundamentally shuts off further inquiry into what is "really" happening in a quantum event. It is a map that says no further maps can be made in this direction and we humans just cannot and will not accept that we cannot continue to make useful maps in some particular direction.
2. There are other concepts being discovered to describe phenomenon at macroscopic levels that look very much like Bohm's interpretation of QM. Specifically, Christopher Alexander (building architect) has shown that there is a deep context dependence to reality at a macroscopic level.
3. A new view is beginning to develop and strengthen from a number of diverse fields that there is a "wholeness" principle operating that is non-local and arises fundamentally from the very geometry of how "things" are related - that, in fact, space-time itself arises from a geometry or relationship of something more fundamental.
A key aspect of this new view is related to the meaning of "information" or "meaning" itself. Bohm's ontological interpretation of the wave function is that it points to a "mechanism" or that carries information within the system. It is a "guidance" or "pilot" wave that carries information to the actual particle about its context and thus guides the particle in its interactions. The appropriate understanding then of this information being carried in a wave form that spreads out in space is that it carries potentialities that only become actualized (become actualities) after significant enough interactions with other particles. Thus, if a particle does not interact enough with other particles it continues to have significant potentiality (many possible actualities that overlap). This then explains why particles can continue to be "entangled" (wave function overlapping) even when they are speeding away from each at the speed of light - they simply have not interacted with enough other particles to have their now separate wave functions be completely non-overlapping and thus have new separate possible futures.
A simple analogy is a radio. The radio is analogous to a particle and the radio waves that it detects and "plays" are analogous to the wave function. Two radios that are separate from each other will be playing the same music because they are guided from the information in the radio waves that they are both decoding.
Notice how the fact that these radios are "entangled" because they are decoding the same radio wave clearly does not in any way allow them to send messages to each other.
The amazing similarity between Bohm's interpretation at the quantum level and Alexander's interpretation at a macroscopic level can be found in "The Undivided Universe" by Bohm and Hiley and "The Nature of Order: The Phenomenon of Life" by Christopher Alexander.
God has created a wonderful play-land for us to explore - now, and in my opinion, for an eternity to come.
thanks,
Iconoclast
"The benefit overran the merit the first day, and has overrun the merit ever since. The merit itself, so-called, I reckon part of the receiving." - Ralph Waldo Emerson | | Back to Top | | |
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Iconoclast
Registered Member
Date Joined Oct 2001
Total Posts : 1227
| Posted 11/27/2003 7:09 AM (GMT -6) | | AlanRhoda
In this case it is not the soul or mind acting upon the body, but rather an embodied agent acting.
Magneton
At the deepest level, however, encompassing all of reality (a kind of state function of the universe), the deterministic aspects of his view seem inescapable, but he views this as a trivial case.
Iconoclast
What if there is a fundamental duality of "particle" and "wave" where particle is physical reality and wave is "information".
Then we could say that physical reality is in a sense fundamentally deterministic but linked to information in that this physical reality responds or is guided by information. If the information itself is not deterministic then we would have to say that the whole system is partly deterministic and partly indeterministic.
We could also then say that Imago Dei means that we are fundamentally "information" but are information embodied in a physical body that primarily responds to "our" information or is primarily guided by our information. We could then understand ourselves as being like the wave function where in our thoughts many overlapping potentialities or possibilities exist that we can actualize. We actualize possibilities by making them irreversible when we interact enough with other physical entities. Two people become "one" when their wave functions totally overlap - when they become bound together - when they share their information so strongly they become correlated.
One way of understanding how we as information dramatically affect physical reality is that physical reality is highly context dependent in a very subtle non-linear and therefore chaotic way. Thus, we dramatically affect large-scale reality by bringing things together to form a new context.
When we bring the thought "Jim is evil" together with our speaking apparatus (our mouth) together with Jim being in the room right next to us we create an irreversible situation. If we just had the thought "Jim is evil" but then refuse to bring it together with any other context it is simply a potentiality that never gets actualized - it is information that never becomes active or realized.
thanks,
Iconoclast
"The benefit overran the merit the first day, and has overrun the merit ever since. The merit itself, so-called, I reckon part of the receiving." - Ralph Waldo Emerson | | Back to Top | | |
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markporter
Fire over Oxford
Date Joined Oct 2003
Total Posts : 263
| Posted 11/29/2003 12:13 PM (GMT -6) | | great responses guys. Thanks.
quote:
Two people become "one" when their wave functions totally overlap - when they become bound together - when they share their information so strongly they become correlated.
well, methinks you're unlikely to find that in a wedding service any time soon.....
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markporter
Fire over Oxford
Date Joined Oct 2003
Total Posts : 263
| Posted 12/3/2003 4:40 AM (GMT -6) | | quote:
Then there is String Theory. . .
So what does string theory have to say about determinism?
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