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Largo
Sport climber
The Big Wide Open Face
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Topic Author's Reply - Sep 10, 2014 - 08:23pm PT
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According to this interpretation, the probabilistic nature of quantum mechanics is not a temporary feature which will eventually be replaced by a deterministic theory, but instead must be considered a final renunciation of the classical idea of "causality."
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Problem is, while the Copenhaggan authors were the best in the field back then, a physicalist of the fundamentalist genre (scientific and religious fundamentalsts are coming from the very same place) can NEVER accept this "final renunciation" because it also cuts deterministic fundamentalism off at the knees as well. You can't have a fully deterministic world where the reductionism stops at a certain level - meanign yhou can ony reduce so far and then it's all bets are off. For a fundamentalist, it's always all-or-nothing. When that thought distortion is applied to mind, which is NOT qualitatively like the other aspects of reality that are mechanistically explained, we get all your howlers like, "Mind is wht the brain does."
IMO, a staunch determinist is doing the same sideways tango that Dingus was doing in insisting that all reality is comprised of things. It makes us feel secure to believe in such "things" till the experts tells you there are no such things in the way your sense organs tell you there is.
JL
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MH2
climber
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Sep 10, 2014 - 09:51pm PT
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You sound confused, JL. A macroscopic system can be quite predictable and 'deterministic' despite the irreducibly probabilistic description of the quantum bits it is made of. The uncertainties smooth out in the average. The brain is quite likely such a macroscopic system. Your objection would equally well apply to digital computers. Is it a howler that, "Software is what a computer does?" Is our understanding of machines impossible because of quantum uncertainty?
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Ed Hartouni
Trad climber
Livermore, CA
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Sep 10, 2014 - 11:20pm PT
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not sure why HFCS would think I would be in disagreement with the Steves...
if he had watched Steve Weinberg's interviews on YouTube he would have run across the sentiment that in the end, we cannot know with certainty the mystery of our existence...
but back to quantum mechanics.
The Copenhagen Interpretation of quantum mechanics is just that, an interpretation, and it has problems. But it has problems because the quantum mechanics isn't something that we experience directly. As MH2 said, quantum mechanics gets "averaged over," when you've got a lot of quantum mechanical things together.
Chemistry is quantum mechanical, but there are still unexplained phenomena. All the quantum mechanical steps of photosynthesis, for instance, have not been worked through. Quantum mechanical systems at finite temperatures do not have solutions. Many body systems that are quantum mechanical (nuclei for instance) are not understood at the level to explain the phenomenology of our measurements. This would include things like neutron stars and the early universe.
All this would be glossed over by HFCS, who is a very big cheerleader for science and expects there to be solutions to all these questions someday. But the details matter, and quite a lot, in the understanding.
I don't think the Steves would disagree, they've spent their lives tracking down the details, and getting some things significantly wrong. But wrong is what science is all about... you have to produce an argument quantitatively capable of being wrong. HFCS hasn't done any of that... of course.
but jgill asked about causality in quantum mechanics... I think this can get difficult... there is a strict sense of causality in the sense of relativity, that is, a system is in causal contact with another system if they lay within each other's "light cone." So for instance, if an electron "emits" a photon which takes off at the speed of light, there are other electrons it can encounter and interact with, and this forms a causal connection. At some time after the emission of the photon, there are some electrons in positions that the photon can get to, but there are other electrons which the photon cannot get to. This later case of electrons are outside of the "light cone" and cannot interact with the emitting electron.
this scenario follows Largo's construction of causality, event A causes event B causes event C, etc... step by step.
Now the interesting problem with our understanding of quantum mechanics is that we cannot describe all of the steps.
Look at the description:
http://en.wikipedia.org/wiki/Copenhagen_interpretation
and you find talk about the "collapse of the wave function" which physicists also refer to as the "measurement problem." We have no description of how this happens, so if we have a statement like "an electron absorbs a photon" or the time reversed process "an electron emits a photon" we're talking about collapsing a wave function (the combined state of a photon and an electron) into the state of a photon and the state of an electron, separately.
We actually don't know how this happens. So we don't have a "causal step" which can be describe... we have a way of treating it in our quantum mechanical description of the process without having to actually understand it physically.
But that is certainly a recipe that leaves us open to surprise.
John Bell thought deeply about the other aspect of quantum mechanics. It is a response to the Einstein criticism that there must be a "hidden variable" that is deterministic. In a famous paper by Einstein, Podolsky and Rosen they formulate a paradox, referred to as the EPR paradox.
http://en.wikipedia.org/wiki/EPR_paradox
The proposed a "thought experiment" where a quantum mechanical system with no intrinsic angular momentum (called "spin") emitted two photons. Now photons have spin equal to 1, but they can be in a state of +1 or -1. The initial system's angular momentum forces the photon's spin, one must be +1 the other -1.
Now we don't know which photon has +1 and which as -1. All that matters quantum mechanically is that the two photon state have net zero spin. So we write the wave function of the photons as a combination of the two possible states.
The photons fly off, let's say we arrange it in a vacuum, 1 kilometer in one flight path, and 1 kilometer + 1 meter along the other flight path. At the end of both flight paths we have a polarimeter that can measure the spin of the photons.
When the shorter path measures it's photon to be, say +1, then we know that the other polarimeter will measure its photon to be -1. The two measurement devices are more than 6 microseconds of light speed travel apart, so the are causally disconnected. But before we make the second measurement, we know that it has to have the opposite spin of the first measured photon, we've "collapsed" its 50-50 wave function into a definite state, and in so doing, determined the state of the second photon, which had been, before that measurement, the opposite 50-50 wave function state.
We don't have a description of the "measurement" process, and it seems like our measurement of one photon "changes the universe."
EPR asks, how is it that the second photon "knows" that it has to be in the other state? EPR goes on to conclude that something is missing from quantum mechanics that makes the determination. In particular, the speculate that there is some underlying theory that is deterministic and is hidden from our observations.
Bell's Theorem basically formalized this thinking.
http://en.wikipedia.org/wiki/Bell%27s_theorem
And provides an avenue to test whether or not the world is quantum mechanical, or if there are some hidden variables. The experimental evidence is that the world is "truly" quantum mechanical, that there are no (actually there can be no) hidden variables.
Interestingly, to have a quantum mechanical universe as is indicated experimentally, physicists have to give up one of three attributes for the theory: locality, realism or freedom.
Locality is very fundamental and is essentially the causality discussed above. It is the basis of field theories and essentially we wouldn't know what to replace it with.
Freedom is the notion that the measurement process is independent of the measured process (think free will).
Realism is the idea that the parts of the theory correspond (e.g. one-to-one) with reality.
Bell initially considered Locality and Realism... but the "free will" aspects were brought in as another assumption of theories.
For those physicists that think about this sort of thing, Realism is the sacrificed attribute. That is, the theory does not have to be physically realistic.
This is a bit more complicated, look at "counterfactual definiteness"
http://en.wikipedia.org/wiki/Counterfactual_definiteness
It would be easy to dismiss all of this as just the idle speculations of a theorist, but the work of Bell was the foundation of modern quantum information theory, including cryptography and computing, now a vast enterprise of commercial interest and national security importance.
The possibility of quantum computing essentially puts all cryptographic codes based on the "impossibility" of factorizing keys at risk. Which is to say, all of them, as quantum computers would be capable of factorizing those keys efficiently and quickly.
But in some ways, we give up on the idea that quantum mechanics is a "one-to-one" mapping of the universe onto our theory, it is not a "realistic" theory. Einstein wouldn't accept that because such an idea didn't agree with his aesthetic taste.
One could say this is all a matter of semantics... but actually Bell's theorem tells you that it isn't just semantics.
Now quantum mechanics is a wonderful theory capable of precise predictions and calculations verified experimentally. In this discussion, it is interesting to ponder the philosophical idea that we can have a theory which is "correct" but which is not "realistic."
Maybe the Steves have talked about Bell's theorem and the EPR paradox in one of their popular works accessible to HFCS... HFCS can take it as a "homework" assignment to report back what the Steves have to say about it.
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MH2
climber
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Sep 11, 2014 - 06:52am PT
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to have a quantum mechanical universe as is indicated experimentally, physicists have to give up one of three attributes for the theory: locality, realism or freedom. (Ed H)
And that should satisfy Largo. Meditation also can lead to questioning 'ordinary' perspective. I think that is as much of a connection as one can make. JL has interesting things to say but goes overboard sometimes trying to give examples of where other people "Don't get it."
Cheers for Ed.
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High Fructose Corn Spirit
Gym climber
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Sep 11, 2014 - 07:01am PT
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All this would be glossed over by HFCS, who is a very big cheerleader for science and expects there to be solutions to all these questions someday.
This is incorrect. (This type of caricature goes over like a lead balloon, very lgo-esque.)
HFCS can take it as a "homework" assignment to report back...
Not.
causality, event A causes event B causes event C...
Just the basis of pretty much all problem solving in engineering and biology and life at large, lol!
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re: causality or causation
When EdH isn't caviling, he's complicating. Why? Why does he do this? Esp as he knows this is a climbing site, not a graduate class in qm or high energy physics.
Scientists and engineers speak of "laws" of causality, "laws" of probability ("laws" of chance), along with "truths" of science, etc. and by and large don't quibble over the meaning of such terms in their work as they get on with practical problem solving.
I have a busy day, but is EdH able to agree on even so basic a statement as this...
There is a fundamental rule (I better not use "law") that governs the entire universe: Causes happen before effects and not the other way around.
Agree, EdH ??
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EdH, just curious if you've had a full year - formal academic study - of organic chemistry (for many people not in the know, many physics majors and engineering majors end up missing this) and how much physical chemistry, biochemistry and molecular biology you've had in your science career. Thanks in advance for a reply.
(I ask because, you see, I've had these. I didn't get this knowledge from pop science reads as several of your recent posts directed my way seem to suggest this is how i get my science.)
PS I'll also post my GRE scores, too, in verbal, math and biology (my "subject" area) if you'll post yours.
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High Fructose Corn Spirit
Gym climber
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Sep 11, 2014 - 07:14am PT
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One more EdH might be willing to chew on at some point today. Let's take Jupiter. A megalomation in turmoil. Can be conceived as a HUGE weather system. Or a huge super weather system of many smaller weather systems distributed around its sphere and to its extreme depths.
re: "determinism"
Now in the view of many, Jupiter is a completely determined system in terms of cause n effect (one past, one present, one future defined by system states and inputs) although indeterminate (not determinable) in terms of prediction.
Does EdH share this view? Repeat: Does EdH share this view? Does EdH understand the question, what is being asked? To EdH is the question meaningful or not meaningful (unmeaningful)?
Gotta go. But I'll be back. :)
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WBraun
climber
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Sep 11, 2014 - 07:51am PT
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In our conditioned consciousness we are imprisoned within a certain number of fixed dimensions.
And by the the admissions of modern science there are at least 11 dimensions.
Perception is subjective and depends on consciousness.
Consciousness is the root instrument for obtaining knowledge.
The higher the consciousness the more one sees that which is always already there.
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High Fructose Corn Spirit
Gym climber
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Sep 11, 2014 - 08:29am PT
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re: pop science writing, books, etc.
It's well known that Carl Sagan, bitd, got a lot of criticism from fellow scientists in his efforts to popularize science. Many have since talked about this period of his life at length from Ann Druyan (his wife) to Dawkins to Tyson and others.
So I can't shake the feeling that EdH, due to his dissing or nigh dissing of popular science reading of late - perhaps more so the case were he 10-20 years older during the 1960s - would have been one of these critics of Carl Sagan, one of the critics of this quibbling, supercilious, now so 20th century retro, camp.
I could be wrong here. If so, it would be informative / insightful I think to get EdH's input /take on this issue, namely Sagan's pioneering popularization of science in the 60s and the heat he got for it (a heat that lasted a good 20 years or more till a next generation of thinking arose and came about).
Today we need popularizers of science more than ever. So... kudos to Tyson, Hawking, Dawkins, Sagans, and all the others. Where "glossing" over the details is incorrect or sloppy in pop science, I am confident that at some pt they are called out for it, partic among the scholarly, the competent, the non-schlups. Correction mechanisms exists in and out of science, in science communications too, in pop science, too.
That I am an avid reader nowadays of these pop science "rags" is simply a part of my work. Which is why I partake in it.
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High Fructose Corn Spirit
Gym climber
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Sep 11, 2014 - 08:49am PT
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If Largo's communications with Matt S. the physicist would lead to his weighing in on...
(1) the causality that undergirds the solar system (earth not exempt, my stance; living things incl us anthropes not exempt, also my stance) in terms of constraint by cause and effect (my interest, stance, all along) ... or
(2) "determinism" (variety of forms)... or even...
(3) "free will" (variety of forms)...
...I'm sure one or two if not more would welcome it. He appears to appreciate popularizing science in writing and he appears to be a very plain, straightforward, clear writer who has a good sense of what it means to meet one's audience.
http://profmattstrassler.com/about/about-me/
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Perhaps Prof Matt could start here...
Now the interesting problem with our understanding of quantum mechanics is that we cannot describe all of the steps. -EdH
Okay. That we cannot "describe all the steps" does NOT imply that systems of the solar system, for eg, are not completely mechanistic (rule bound) or not completely deterministic in terms of causation (cause n effect), however one prefers to say it.
This solar system (taken as a closed system, no quibbling necessary here) is constrained by one trajectory through state space from its origin to its eventual end; and most importantly we humans are a part, one part, of this ONE trajectory - not apart from it, not outside it, not exempt from it in any way as so many humans along with their egos across history have wished. This is so whether or not we have a model or description (of steps) of it. So there it is, the claim. The unknowns of QM aside, fully supported by science, I say, and most importantly fully reasonable.
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High Fructose Corn Spirit
Gym climber
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Sep 11, 2014 - 09:51am PT
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"Interestingly, to have a quantum mechanical universe as is indicated experimentally, physicists have to give up one of three attributes for the theory: locality, realism or freedom.
Locality is very fundamental and is essentially the causality discussed above. It is the basis of field theories and essentially we wouldn't know what to replace it with.
Freedom is the notion that the measurement process is independent of the measured process (think free will).
Realism is the idea that the parts of the theory correspond (e.g. one-to-one) with reality.
Bell initially considered Locality and Realism... but the "free will" aspects were brought in as another assumption of theories."
..................
Who's the audience here?
(I guess MH2 gets it, though. Although that's weird because he's never seemed to ever draw a distinction between the different forms of "determinism" - most notably the one of cause n effect (causation) and the one of prediction (ref: Lapace's Demon). Weird.)
But I am not clear on this. Esp taken as a whole. Too bad the Steves aren't climbers who visit this site. Perhaps they'd be able to translate? In a pop science form?
That I'm not clear on this snippet doesn't surprise though. As I still have fresh memory of how a couple exchanges involving such simple things - "truths" of science and "Ohm's Law" were obfuscated. Needlessly. With quibbles. :(
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MikeL
Social climber
Seattle, WA
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Sep 11, 2014 - 10:07am PT
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Dang, Ed, that was a great set of comments. Wonderfully articulated. TFPU.
And what Werner said.
(In my world, both provide keen insight.)
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High Fructose Corn Spirit
Gym climber
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Sep 11, 2014 - 10:34am PT
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Here it is, from another perspective...
The Steves (Steven Weinberg, Stephen Hawking), Leonard Mlodinow, Peter Atkins (a physical chemist), Sean Carrol... some of those who have come my way (per pop s reading of course) and lots of others I'm sure... barring Tipler, of course, lol!... all "believe" our world - tho indeterminant/ unpredictable in any deep sense - is deterministic in the causal sense (iow, fully caused, fully constrained, by causation; or if you prefer by underlying mechanistic "rules" of the universe).
So why doesn't EdH? Or if he does, per this...
not sure why HFCS would think I would be in disagreement with the Steves...
why does he quibble so?
Further, each and every one of the aforementioned physicists also rejects - per their explicit statements in their pop science books - "free will" as its commonly conceived in its most popular form in the English speaking world.
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Tvash
climber
Seattle
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Sep 11, 2014 - 10:43am PT
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EdHs post and links were very interesting. i dont pretend to grok all of the material - Bell's reasoning against hiddn variabls as an explanation for quantum entanglement (a causality paradox) for example .
Causality can be tricky in a quantum world. What causes a mistake in DNA replication that results in a robust mutation? What causes a particle collision to parent 2 photons instead of another particle/anti particle pair? What caused the Big Bang?
Given that the quantum world is our world (Big Bang), it seems as though the nature of causality is still an open question.
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High Fructose Corn Spirit
Gym climber
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Sep 11, 2014 - 10:52am PT
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Causality can be tricky in a quantum world.
Yet all of chemistry for example (mass csq of the quantum world at work) stands as testimony, evidence, to the underlying causality that defines our lives. So, too, does all the order that characterizes our world down through the ages and around the world that makes everything work as they do - from evolution to digestion to photosynthesis to climbing to flying in big jet airliners. They all represent order, causation. Which is all the stance I'm taking yet gets so much blowback. Ultimately people just don't want to give up on, or to let go of, their ghost in the machine (concept and tradition) and its free will.
the nature of causality is still an open question
Two points:
Only if you haven't been standing over the jig-saw puzzle for a long time.
Only if you're seeking something of an absolute answer instead of a reasonable one.
What causes a mistake in DNA replication that results in a robust mutation?
Random physico-chemical happenstance. A G in lieu of an A at just the right or wrong time and place. There's one possible answer: Completely caused. At the microscopic, mol biological level. And at this level, completely understood.
Random does not mean non-caused.
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Tvash
climber
Seattle
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Sep 11, 2014 - 11:17am PT
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random physico (?) chemical happenstance is completely caused and understood?
Does the Big Bang also fall into that category?
If one cannot answer the question: what conditions caused this outcome rather than another possible one, as with the examples ive presented, then an incomplete understanding od causality is indicated.
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High Fructose Corn Spirit
Gym climber
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Sep 11, 2014 - 11:22am PT
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Sure it is. Take a molecular biology course. The physical chemistry of replication along with all the other mechanisms of action are completely understood.
This just shows part of the problem here.
Further, maybe you do or do not know. Even our DNA repair mechanisms at the level of DNA replication are selected for. Just so there's just the right balance of repair/ mutation going on, ultimately leading to robust life as an effect. Again, here's yet another micro-eg that speaks to the order, otherwise the causality underlying the order, of our mol biology. That once past Abrahamic religion and theism some of us might be inclined to call something of a "miracle."
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Tvash
climber
Seattle
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Sep 11, 2014 - 11:34am PT
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Share this complete understanding by addressing my questions then, for a syllabus does not an explanation make. I know the mtrl you've summarized already, BTW. It doesnt address the questions.
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High Fructose Corn Spirit
Gym climber
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Sep 11, 2014 - 11:40am PT
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What is the question?
Help me out. Be specific.
For context...
If it concerns understanding, I'm saying at the level of mol biology replication and how it's interferred with fidelity wise is understood. There are entire families of known mechanisms of action that affect, guide, interfere with, repair, etc. replication.
I mention replication only because you brought it up.
If an A is substituted incorrectly in lieu of a G say in a matchup with C, that is (1) your mutation, (2) a possibly random but certainly caused event, (3) a known and understood mechanism of action.
What more can I say?
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But you better be quick, I can't hang here all day, lol!
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Ed Hartouni
Trad climber
Livermore, CA
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Sep 11, 2014 - 11:54am PT
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HFCS- I've noticed you tend to take my explanations as being "obscuring" when they seem to be saying something contrary to your beliefs. So instead of questioning your beliefs, you are would rather assume that, since I am a scientist, I am poorly representing what scientists know. If I were better, the explanations would affirm your beliefs.
The language we discuss science is not written in these words, it can be highly mathematical, and very technical. And there is a reason for that, many of the new knowledge has to define new meanings to appropriated vocabulary.
The idea of what an "up quark" or a "down quark" cannot necessarily be gleaned from the dictionary. And even the definitions that are there do not do justice to the physical ideas, and especially to the domain of applicability and the limitations of those ideas.
What Bell's theorem, and the subsequent experimental investigations of quantum mechanics tells us, is that our quantum mechanical causal chain, "event A causes event B causes event C, etc..." may not be "realistic." Though the theory correctly calculates the outcome of experiments to high accuracy.
It's not clear that this has any profound implications to the way physicists use quantum mechanics or even think about that... though getting there did open up new avenues of research. The phrase "entangled states" didn't exist when John Bell did his work, those are later concepts that came out of the work that he initiated in his investigations.
as far as Jupiter, we understand, roughly what Jupiter is and we can produce descriptions of how Jupiter "works." In our reductionist approach it requires the knowledge of how atoms interact in a very wide range of pressures and temperatures. Getting that knowledge and applying it to the problem of Jupiter results in many different physical insights, not all of them apparent before. We can say that we understand Jupiter, but when we say that as a scientist, it means we can calculate the outcome of observation, there is a sense of what quantitative agreement is...
as far as credentials, my adolescent rebellion was to become a high energy physicist, as my Dad was a physical chemist/solid state physicist... I avoided chemistry and what I know about organic chemistry is a rather slender chapter in Feynmann's Lectures in Physics, volume 3. That is probably a better vantage point for starting to suss out the quantum mechanics of photosynthesis.
Quantum systems are robust because the energy quanta required to move them from one state to another effectively allows us to consider the systems at zero temperature. In most systems we are successful at computing, this "zero temperature" assumption is extremely good. Schrodinger discusses this in his treatise "What is Life?" and this quantum mechanical attribute of DNA (which Schrodinger didn't know about when he wrote the treatise) is essential for the stability of the molecule. It is the reason why DNA's information isn't degraded by thermal interactions.
But that isn't the issue with photosynthesis, which is thought to be an example of a finite temperature quantum mechanical problem, which has also eluded our attempts to work out the quantum mechanical nature of the "causal chain" quantitatively.
These are all "quibbles" but they are not insignificant quibbles... especially when making expansive claims.
I'm sorry for the length of this post... obviously I can't write copy for newspapers, or scripts for popular science programs on TV. And I probably can't inspire rock climbers with beautiful language regarding what it is all about...
oh, credentials?
I was an undergraduate at UC Berkeley and received an undergraduate degree in Physics
my graduate work took place at Columbia U. and wrote a dissertation in experimental High Energy Physics for my physics Ph.D...
that was followed by a post-doc and then a teaching position at U. Mass from which I departed for work at LLNL (I think all of this could be found somewhere on the web).
I'm a coauthor on over 200 papers.
But I have to agree that the Steves are awesome!
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High Fructose Corn Spirit
Gym climber
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Sep 11, 2014 - 12:01pm PT
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So for starters do you agree with the Steves - just as they have explicitly stated - that all lines of evidence point to the universe - or if you don't like that - the milky way - as causal deterministic? It boils down to a simple qt and ans here. I think you know enough to split the hairs (to nuance) on causal determinism vs computable or computational determinism.
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Regarding causality, are you able to respond here as written...
There is a fundamental rule that governs the entire universe: Causes happen before effects and not the other way around.
Agree or disagree?
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Yes, your academic credentials are most impressive. At the same time, I hope you would agree that not having had a few formal years of organic chemistry through mol bio has probably not left you with a deep and abiding sense of... mechanisms of action... in these areas of nature... as thoroughly as they otherwise might have.
This is important because causality or causation - either in biophysical terms or bioengineerng terms - accompanies these so-called "mechanisms of action" start to finish and one can look at the whole shebang of them all as quite literally the basis for all life, for all biology and of course ourselves. Hence the relevance.
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I've noticed you tend to take my explanations as being "obscuring"
Insofar as they're obscuring or "obfuscating" - imo- it is because you seem to reduce just about every topic - even straightforward biologic or electronic ones - to energy or particle physics. When it seems to me this is unnecessary. Were we to go out, climb together, and along the way discuss the statics of the American Triangle to a couple of noobs on our belay ledge, could we do it without the energy or particle physics? could we do it just in terms of so-called engineering physics? I don't know. I'd like to think we could though.
when they seem to be saying something contrary to your beliefs...
Again, no. Just more lgo-esque repartee here, me thinks. What is fair to say though, is that my thinking, my concepts and/or models of how life and the planet work (as developed across a life in science), and last but not least, yes, my "beliefs" as well - are pretty much aligned with those of the "popularizers" I've cited. Of which I'm okay with, I guess I'll have to be.
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