Quantum Darwinism

If one major thesis running through this blog is panrelationalism then another is the applicability of the basic premises of the Darwinian theory of evolution to almost any area of inquiry. Below is an article published in nature.com in 2004 describing how Wojciech Zurek and colleagues have attempted to show how a Darwin-like process of selective propagation of information can be used to describe the transition from quantum to "preferred" classical states:

If, as quantum mechanics says, observing the world tends to change it, how is it that we can agree on anything at all? Why doesn't each person leave a slightly different version of the world for the next person to find? Because, say the researchers, certain special states of a system are promoted above others by a quantum form of natural selection, which they call quantum darwinism. Information about these states proliferates and gets imprinted on the environment. So observers coming along and looking at the environment in order to get a picture of the world tend to see the same 'preferred' states.

If it wasn't for quantum darwinism, the researchers suggest in Physical Review Letters, the world would be very unpredictable: different people might see very different versions of it. Life itself would then be hard to conduct, because we would not be able to obtain reliable information about our surroundings... it would typically conflict with what others were experiencing.

The difficulty arises because directly finding out something about a quantum system by making ameasurement inevitably disturbs it. "After a measurement," say Wojciech Zurek at Los Alamos National Laboratory in New Mexico and his colleagues, "the state will be what the observer finds out it is, but not, in general, what it was before."

Because, as Zurek says, "the Universe is quantum to the core," this property seems to undermine the notion of an objective reality. In this type of situation, every tourist who gazed at Buckingham Palace would change the arrangement of the building's windows, say, merely by the act of looking, so that subsequent tourists would see something slightly different. Yet that clearly isn't what happens. This sensitivity to observation at the quantum level (which Albert Einstein famously compared to God constructing the quantum world by throwing dice to decide its state) seems to go away at the everyday, macroscopic level. "God plays dice on a quantum level quite willingly," says Zurek, "but, somehow, when the bets become macroscopic he is more reluctant to gamble." How does that happen?

The Los Alamos team define a property of a system as 'objective', if that property is simultaneously evident to many observers who can find out about it without knowing exactly what they are looking for and without agreeing in advance how they'll look for it. Physicists agree that the macroscopic or classical world (which seems to have a single, 'objective' state) emerges from the quantum world of many possible states through a phenomenon called decoherence, according to which interactions between the quantum states of the system of interest and its environment serve to 'collapse' those states into a single outcome. But this process of decoherence still isn't fully understood.

"Decoherence selects out of the quantum 'mush' states that are stable, that can withstand the scrutiny of the environment without getting perturbed," says Zurek. These special states are called 'pointer states', and although they are still quantum states, they turn out to look like classical ones. For example, objects in pointer states seem to occupy a well-defined position, rather than being smeared out in space.

The traditional approach to decoherence, says Zurek, was based on the idea that the perturbation of a quantum system by the environment eliminates all but the stable pointer states, which an observer can then probe directly. But he and his colleagues point out that we typically find out about a system indirectly, that is, we look at the system's effect on some small part of its environment. For example, when we look at a tree, in effect we measure the effect of the leaves and branches on the visible sunlight that is bouncing off them. But it was not obvious that this kind of indirect measurement would reveal the robust, decoherence-resistant pointer states. If it does not, the robustness of these states won't help you to construct an objective reality.

Now, Zurek and colleagues have proved a mathematical theorem that shows the pointer states do actually coincide with the states probed by indirect measurements of a system's environment. "The environment is modified so that it contains an imprint of the pointer state," he says.

Yet this process alone, which the researchers call 'environment-induced superselection' or einselection, isn't enough to guarantee an objective reality. It is not sufficient for a pointer state merely to make its imprint on the environment: there must be many such imprints, so that many different observers can see the same thing.

Happily, this tends to happen automatically, because each individual's observation is based on only a tiny part of the environmental imprint. For example, we're never in danger of 'using up' all the photons bouncing off a tree, no matter how many people we assemble to look at it.

This multiplicity of imprints of the pointer states happens precisely because those states are robust: making one imprint does not preclude making another. This is a Darwin-like selection process. "One might say that pointer states are most 'fit'," says Zurek. "They survive monitoring by the environment to leave 'descendants' that inherit their properties." "Our work shows that the environment is not just finding out the state of the system and keeping it to itself", he adds. "Rather, it is advertising it throughout the environment, so that many observers can find it out simultaneously and independently."

Preferata! Good or bad poetic science?

While reading Dawkins' Unweaving The Rainbow I've been thinking about the distinction between literal and metaphorical description with respect to philosophy and science. The dictionary definitions of the words basically state that literal description gets at the "essential or genuine character of something" whereas metaphorical description is where "a word or phrase that ordinarily designates one thing is used to designate another." It seems to me that the way science sometimes claims to be providing literal descriptions is by inventing new words - by spinning out something from a more familiar term for similar observed or hypothetical phenomena (e.g. gluon* for the force that sticks quarks together), often by taking or amending a (sometimes quasi-) latin synonym (e.g. gravitas, latin for heavy) for what they are describing - thus avoiding the charge of metaphor.

So perhaps I could do the same and invent a word for describing how subatomic particles, chemicals, cells, animals, people, institutions, and everything else we can think of appear to express preferences in their observable behaviour and are in fact definable by the range of preferences they can express and the probability of them expressing them. I could call the smallest unit of anything a preferatum (plural: preferata) and explain their existence and behaviour as being a particular mode of preferation. So, for example, with a sufficiently serious look on my face I could say that it is not that there are electrons which can be said to express preferences but that electrons are in fact a species of inorganic preferata and that experimental data are in fact a record of the preferation from which the existence of electrons is inferred.

*glu·on
n.

A hypothetical massless, neutral elementary particle believed to mediate the strong interaction that binds quarks together.

---

[glu(e) + -on¹.]

Source: The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2000 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.

Values and matter

In Lila: An Inquiry into Morals Pirsig tells us that he was drawn into the metaphysics of values via a failed attempt to contribute something to the field of anthropology in the form of a study of Native American culture and its influence on contemporary North America. He writes:

You can't get anywhere because you are forced to resolve arguments every step of the way about the basic terms you are using. It's hard enough to talk about Indians alone without having to resolve a metaphysical dispute at the end of every sentence. This should have been done before anthropology was set up, not afterward.

That was the problem. The whole field of cultural anthropology is a house built on intellectual quicksand. As soon as you try to build the data into anything of theoretical weight it sinks and collapses. The field that one might have expected to be one of the most useful and productive of the sciences had gone under, not because the people in it were no good, or the subject was unimportant, but because the structure of scientific principles that it tries to rest on is inadequate to support it.

(Pirsig, Lila, Ch.5)

The problem with trying to use "scientific principles" to build anthropological theory, Pirsig states, is that:

Patterns of culture do not operate in accordance with the laws of physics. How are you going to prove in terms of the laws of physics that an attitude exists within a culture? What is an attitude in terms of the laws of molecular interaction? What is a cultural value? How are you going to show scientifically that a certain culture has certain values?

You can't.

Science has no values. Not officially. The whole field of anthropology was rigged and stacked so that nobody could prove anything of a general nature about anybody. No matter what you said, it could be shot down any time by any damn fool on the basis that it wasn't scientific.

(ibid, Ch.4)

So Pirsig identifies the problem as the attempt to reduce values to the physical properties and behaviour of matter. Pirsig's answer to this quandary was to reverse the hierarchical primacy of patterns of matter over values such that matter becomes a particular pattern of values. Then, to the extent that metaphysics determines the purview of science, Pirsig argues that:

If science is a study of substances and their relationships, then the field of anthropology is a scientific absurdity. In terms of substance there is no such thing as a culture. It has no mass, no energy. No scientific instrument has ever been devised that can distinguish a culture from a non-culture.

But if science is a study of stable patterns of value, then cultural anthropology becomes a supremely scientific field. A culture can be defined as a network of social patterns of value. As the Values Project anthropologist Kluckhohn had said, patterns of value are the essence of what an anthropologist studies.

Kluckhohn's enormous mistake was his attempt to define values. He assumed that a subject-object view of the world would allow such a definition. What was destroying his case was not the accuracy of his observations. What was destroying his case were these substance-oriented metaphysical assumptions of anthropology that he had failed to detach from his observations. Once this detachment is made anthropology is out of the metaphysical quicksand and onto hard ground at last.

(ibid, Ch.8)

The reversal of the primacy of matter over values is the key to Pirsig's philosophical solution (the MOQ) to the obstacles faced by an anthropologist and this move, and its validity, will be the focus of the next post. More generally I want to consider how Pirsig's ideas bear up to recent developments in philosophy and science and how well my aontic approach aligns with the MOQ.

Smolin on relational physics

Lee Smolin is a process physicist who I find very interesting to read. The below is from an article featured in Brockman's The Third Culture: Beyond The Scientific Revolution - which you can link to here http://www.edge.org/documents/ThirdCulture/z-Ch.17.html - in which he talks about a relational model of physics as having the potential to provide a theoretical basis for the elusive quantum theory of gravity. Bold italics are my emphasis:

[A]t the Planck scale, which is twenty powers of ten smaller than an atomic nucleus, space looks like a network or weave of discrete loops. In fact, these loops are something like the atoms out of which space is built. We're able to predict that — just as the possible energies an atom can have come in discrete units — when one probes the structure of space at this Planck scale, one finds that the possible values the area of a surface or the volume of some region can have also come in discrete units. What seems to be the smooth geometry of space at our scale is just the result of an enormous number of these elementary loops joined and woven together, as an apparently smooth piece of cloth is really made out of many individual threads.

Furthermore, what's wonderful about the loop picture is that it's entirely a picture in terms of relations. There's no preexisting geometry for space, no fixed reference points; everything is dynamic and relational. This is the way Einstein taught us we have to understand the geometry of space and time — as something relational and dynamic, not fixed or given a priori. Using this loop picture, we've been able to translate this idea into the quantum theory.

Indeed, for me the most important idea behind the developments of twentieth-century physics and cosmology is that things don't have intrinsic properties at the fundamental level; all properties are about relations between things. This idea is the basic idea behind Einstein's general theory of relativity, but it has a longer history; it goes back at least to the seventeenth-century philosopher Leibniz, who opposed Newton's ideas of space and time because Newton took space and time to exist absolutely, while Leibniz wanted to understand them as arising only as aspects of the relations among things. For me, this fight between those who want the world to be made out of absolute entities and those who want it to be made only out of relations is a key theme in the story of the development of modern physics. Moreover, I'm partial. I think Leibniz and the relationalists were right, and that what's happening now in science can be understood as their triumph.

[....]

The picture that emerges from both relativity and quantum theory is of a world conceived as a network of relations. Newton's hierarchical picture, in which atoms with fixed and absolute properties move against a fixed background of absolute space and time, is quite dead. This doesn't mean that atomism or reductionism are wrong, but it means that they must be understood in a more subtle and beautiful way than before. Quantum gravity, as far as we can tell, goes even further in this direction, as our description of the geometry of spacetime as woven together from loops and knots is a beautiful mathematical expression of the idea that the properties of any one part of the world are determined by its relationships and entanglement with the rest of the world.

Causation as Folk Science

I've found an interesting article on the role of causality in science written by John D. Norton (University of Pittsburgh). The abstract and conclusion, cited below, provide a good summary of his position. It seems to support my understanding that debates about the metaphysics of causation have largely given way to a pragmatism which is not at all incompatible with dependent origination. Indeed it is interesting to see that Norton talks about "recovering" causation from ontological inconclusiveness much as dependent origination "recovers" conventional reality from the same.

The full text is available at http://www.philosophersimprint.org/003004/

I deny that the world is fundamentally causal, deriving the skepticism on non-Humean grounds from our enduring failures to find a contingent, universal principle of causality that holds true of our science. I explain the prevalence and fertility of causal notions in science by arguing that a causal character for many sciences can be recovered, when they are restricted to appropriately hospitable domains. There they conform to a loose collection of causal notions that form a folk science of causation. This recovery of causation exploits the same generative power of reduction relations that allows us to recover gravity as a force from Einstein's general relativity and heat as a conserved fluid, the caloric, from modern thermal physics, when each theory is restricted to appropriate domains. Causes are real in science to the same degree as caloric and gravitational forces.

(John D. Norton, Causation as Folk Science, 2003, Ch.1)

On the one hand, causes play no fundamental role in our mature science. Those sciences are not manifestly about causation and they harbor no universally valid principle of causality. On the other, the actual practice of science is thoroughly permeated with causal talk: science is often glossed as the search for causes; and poor science or superstition is condemned because of its supposed failure to conform to a vaguely specified principle of causality. I have argued that we can have causes in the world of science in same way as we can retain the caloric. There is no caloric in the world; heat is not a material substance. However in many circumstances heat behaves just as if it were a material fluid and it can be very useful to think of heat this way. It is the same with cause and effect. At a fundamental level, there are no causes and effects in science and no overarching principle of causality. However in appropriately restricted domains our science tells us that the world behaves just as if it conformed to the sort of folk theory of causation outlined above. Finally I have suggested that we need not expect the exact same notion of cause to be invoked in each of these many domains. The proliferation of different account of the nature of causation suggests that there might be no single notion of causation, so that the best single account we can have is a loose folk theory, not all of whose elements will be accepted in every application.

(ibid, Ch.7)