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jgill
Boulder climber
The high prairie of southern Colorado
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Mar 22, 2017 - 10:32pm PT
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The article speaks of functions mapped back onto themselves
Brouwers FPT is unfortunately an existence theorem. That is to say in confirms the existence of at least one such point but doesn't tell you how to find it. This was so distressing to Brouwer that he developed intuitionism - roughly, a constructive approach to proofs (not his FPT). The Banach FPT on the other hand has more restrictive hypotheses but allows computation of the (guaranteed single) FP by simple iteration. That's where the Lipshitz contraction (LC) comes into play.
In general, locating FPs can be a very trying experience if the LC or something similar is not available. Too bad, since FP theory is so useful in a number of disciplines. I think there are some advanced results out there for cases of the Brouwer FPT, maybe involving group theory, but It's beyond me.
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Ed Hartouni
Trad climber
Livermore, CA
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Mar 23, 2017 - 08:22am PT
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I have no dog in the literature dust-up here...
but I did recently acquire a collection of Ted Chiang's short stories after seeing Arrival, curious to read the story that was the basis of the screen-play.
This act, I have to admit, has to do with my aversion of science fiction that violates known physical law... and while the basic premise of Arrival could be considered contentious, it evokes some interesting modern results having to do with "language," which perhaps I'll write about later. I wondered why I like certain science fiction stories that are obviously unphysical and not others... and it may be specific to a story, Ursla Le Guin's Lathe of Heaven was another story I liked a lot...
I don't usually worry so much about other people's opinion about literature, it is easy enough to read it oneself and have that experience... and I seem to read quickly which helps, though I am not adverse to abandoning work that doesn't hold my interest.
Fixed points occur in physics as well, in renormalization groups(Greek to me). Ed might tell us if they crop up elsewhere in physics.
As for Fixed Points in physics, unfortunately the Wiki page doesn't do a good idea describing the significant importance of the idea.
http://en.wikipedia.org/wiki/Renormalization_group
which has at its base the idea of "scaling" which can be a considerably powerful tool in calculating the outcome of an experiment.
One can assume naive scaling, the trick is to show that there is a physical basis for that scaling, but more on this later.
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MikeL
Social climber
Southern Arizona
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Mar 23, 2017 - 09:13am PT
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DMT: You can't blame losing the deal on the plumber.
It’s a generalization that I’ve presented, but it’s not my rule of thumb. I seen it played out in a number of entertainment domains.
Sycorax, my friend, there is no disputing your intelligence and experience in your field as a teacher. I might suggest that you are a “distribution system” of sorts. Write a captivating novel, and things might be different.
Wittgenstein said it was almost impossible to understand your own culture at any one moment. Understanding one’s own culture comes seems to come only historically. Both are constructed and re-constructed and re-invented repeatedly. Seeing that might make one pause in believing what is substantively real for either history or culture.
Look at the rather LONG list of different critical theories in literature and history, for example.
https://en.wikipedia.org/wiki/Critical_theory
https://en.wikipedia.org/wiki/Literary_criticism
(Check out the listings of different period writings on under “key texts” at the bottom of this page.)
Sell a knowing view to people, and they might follow you like the pied piper. As one person told me years ago: “if you can’t dazzle them with your brilliance, baffle them with your bullsh*t.”
(From “Chicago,” the musical . . . )
Give 'em the old razzle dazzle
Razzle dazzle 'em
Give 'em act with lots of flash in it
And the reaction will be passionate
Give 'em the old hocus pocus
Bread and feather 'em
How can they see with sequins in their eyes?
What if your hinges all are rusting?
What if, in fact, you're just disgusting ?
Razzle dazzle 'em
And they'll never catch wise!
Eh Eh Eh Eh
Ah! Ah! Ah!
Give 'em the old razzle dazzle
Razzle dazzle 'em
Give 'em a show that's so splendiferous
Row after row will grow vociferous
Give 'em the old flim flam flummox
Fool and fracture 'em
How can they hear the truth above the roar?
Throw 'em a fake and a finagle
They'll never know you're just a bagel,
Razzle dazzle 'em
And they'll beg you for more!
Ah! Ah! Ah! Ah!
Give 'em the old razzle dazzle
Razzle dazzle 'em
Back since the days of old Methuselah
Everyone loves the big bambooz-a-ler
Give 'em the old three ring circus
Stun and stagger 'em
When you're in trouble, go into your dance
Though you are stiffer than a girder
They let ya get away with a murder
Razzle dazzle 'em
And you've got a romance
Give 'em the old
Razzle dazzle
Razzle dazzle 'em
Give 'em an act that's unassailable
They'll wait a year 'til your available!
Give 'em the old
Double whammy
Daze and dizzy 'em
Show 'em the first rate sorcerer you are
Long as you keep 'em way off balance
How can they spot you got no talents?
Razzle dazzle 'em
Razzle dazzle 'em
Razzle dazzle 'em
And they'll make you a star!
(Sure do miss Bob Fosse)
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MH2
Boulder climber
Andy Cairns
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Mar 23, 2017 - 09:59am PT
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Speaking of razzle dazzle,
The problem is awareness, sentience, or whatever term you wish to choose that underscores the fact that we are aware of the stuff of consciousness. Every effort to try and explain this as information, as mirror neurons, as a state, a processing artifact, and all the rest, is just as absurd
JL March 17
It is never clear to me what JL finds impossible to ever attribute to physical mechanisms. Adding up his comments over the years, it looks as though, as soon as a biological or physical basis for an experience is discovered, that experience shifts from the ineffable first person subjective to the mere third person objective. We move forever down the hot road, the water evaporating as we approach it.
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MH2
Boulder climber
Andy Cairns
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Mar 23, 2017 - 10:02am PT
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I had an idea yesterday about a way to study the brain. It looks as though the molecular building blocks of synaptic spines are coming to be characterized. Synaptic spines are found at the points of contact of axons with dendrites, where changes take place that allow for learning and memory.
Memory may last a long time because it depends on structural changes which last a long time.
Molecules associated with synaptic spines may be affected by activity at the synapse in such a way that a greater area of contact is established, or the strength of the synapse may be modified in some other way.
During the brief interval when molecular complexes are shifting shape or position they may present normally unavailable sites for other molecules to attach.
Now we need a marker molecule that will have access to and hook on to one of the complexes involved in modifying synaptic strength.
We take mice and present one group with a learning situation, leaving the other group alone. We have added our marker molecule to the body fluid of both groups. After learning, which could be a brief affair if we are nasty and use electric shock, or gentle if we train the mice to go into the round hole not the square one to find food, we look in the brain for where our marker molecule has been deposited.
I think it would be fascinating to look at a physical trace of memory. Could we see the interweaving of sight, sound, smell, etc., into the endlessly nuanced personal history we experience inside our heads?
The above idea for looking for memory traces is not likely to pan out. It is also possible that neural network explorations into ways to modify connections will be more fruitful as a path to understanding biological memory.
However, the idea has an analog. During cell division, DNA replicates itself. A good system for studying cell division is the developing chick embryo. If a hole is made in the egg and a radio-isotope like tritiated thymidine is added, the radioactive thymidine will be incorporated where cells are dividing. If you then preserve the embryo in fixative, make thin-section slides of it, and include a photographic emulsion in the slide, the cells which were dividing will gradually show up as radiation activates the silver grains.
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jgill
Boulder climber
The high prairie of southern Colorado
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Mar 23, 2017 - 11:34am PT
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Excellent post, Andy. And you are on target about the Wizard moving the goalposts as physical explanations materialize. He'll never abandon the woo factor, thus encouraging the physicalists to keep pushing the ball downfield.
Thanks, Ed. Of course, aspects of differential equations used in physics depend upon fixed point theory, but that's not the whole ball game apparently.
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Largo
Sport climber
The Big Wide Open Face
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Topic Author's Reply - Mar 23, 2017 - 12:37pm PT
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It is never clear to me what JL finds impossible to ever attribute to physical mechanisms. Adding up his comments over the years, it looks as though, as soon as a biological or physical basis for an experience is discovered, that experience shifts from the ineffable first person subjective to the mere third person objective. We move forever down the hot road, the water evaporating as we approach it.
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My point is always been that there has never been a biological or physical basis provided for the fact that we are AWARE of any of the content of our experience. Provide one, and you have answered Chalmers Hard Problem. Why do you think people continually duck even trying to answer the Hard Problem, or rephrase it in a way that a mechanism can catch hold of a material answer. But none have ever been presented because they are chasing a unicorn = that 1st and 3rd person phenomenon are self same, or that the former is causally derivative of the later. It works that way with every other external object of force, so why not here, right? That's the sticking point, IMO.
As mentioned, in the model I now follow, mind (or the mechanistic generation of content) does in no wise imply that we are conscious of same. One is syntactic and the other is semantic. Apples and oranges.
I think the trouble arises when you don't understand the differences. If you do, you might have a ah-ha moment when you realize that expecting syntactic processes to deliver semantical results is a quintessential non sequitur. It's not even logically coherent. I covered this earlier but maybe this will help clarify the point:
The philosophical blunder called LOTH (language of thought hypothesis) says that if you instantiate (have an instance) the formal ("syntactic") structure of thought and intelligence, then the "semantic" (meaning, experiential) quotient will necessarily and mechanically follow.
Put differently, meaning derives from, and is an inherent property and direct, causal result of, the underlying structure. This is a bottom-up reductive formulation in keeping with the belief that the brain, or neural substrate, "creates" the semantic content of thought.
LOTH, it should be noted, is largely derived from computer modeling, rather than from a comprehensive look at consciousness itself. Common to the mythology of Hard AI (derived in large part from long ago-junked behavioralism), if we possessed an accurate account of consciousness purely in terms of input, and the most primitive syntactic processes thereof, this external, mechanistic description, by definition, will fully describe and explain both the semantic quotient and first-person experience itself.
Through this basic logical blunder, syntactic process is falsely believed to be identical to, or the source of, semantic phenomenon, just as (it is believed) brain states are to some (identity materialists), identical to conscious states.
Searle and many other say - not at all. Structure nor yet processing DOES NOT imply meaning, and certainly not the awareness of it. A machine that can merely mimic the formalized structure of conscious thought, language and behavior (the "output") is merely a "syntactic engine," no more conscious than your desktop computer, or for that matter, Vulcan, the most powerful computer in the world.
In the end, when the implications of are held up to the light, LOTH is just another stab at trying to conflate consciousness and first person subjective experience with objective functioning, that "we only think we have experience," but what's really going on are simply the structural stirrings of the brain.
That is the dead-end that one is left in when limiting the field of inquiry to 3rd person phenomenon. It's as futile (in terms of understanding consciousness) as using the 1st person to try and do material science.
Even though this tact has made no progress in addressing the Hard Problem, or showing what experience IS, it raises the question why people remain so invested in this panning out, once more data is in. I think the answer is obvious.
It might boil down to something as basic as people not actually believing that consciousness is a unique phenomenon in the known world, though it clearly is. We can't even use mataphorical language to accurately discuss consciousness because it is totally unlike any other phenomenon we can list or even imagine. Virtually every other phenomenon can be observed, measured and explained as an external object or force. Conversely, consciousness is incontrovertibly private, know directly only to the host subject, and not itself accessible as sense data. We simply cannot read Ed's mind or feel his feelings or directly experience his memories and sensations from a 3rd person POV.
Accepting this is so, for many the inquiry shifts from direct to indirect, from 1st person to 3rd person, and in the process the question shifts to possible causal links believed to "source" in some fashion to mechanically "cause" consciousness. After all if you compromise the brain or the neural substraits of consciousness, consciousnss itself is compromised or seemingly dies altogether. This leads to all the canny workarounds and conflationary strategies to posit consciousness itself as data, or processing, or a mechanical function, or some damned thing we can get hold of and quantify as sense data. But it can't be done for a couple simple reasons.
Causal argument can only explain the energetic and material links between material, or at any rate, phenomenon that are directly measurable. Heat on the kettle full of H2O "causes" steam, a phenomenon we can see and measure a variety of ways. Put differently, whatever is caused by one measurable object or force is never itself more than another directly measurable object or force.
In the case of consciousness, a mechanistic brain model is left to try and explain how WHAT it supposedly causes (consciousness, experience) is NOT itself directly observable or measurable. Moreover, what does "explaining" actually mean in this regards, and what is it that this model is trying to explain, since in every other case in scientific history, "it" is an external object or force.
What's more, science is totally adverse to considering a phenomenon that exists above and beyond the physical parts involved. Note the catchphrase: What isn't physical? This therefore leads to the inevitable conclusion that this slippery non-thing call consciousness has to be artifact of the brain itself. And since we cannot see it or measure it directly, people point to some aspect of objective functioning and say, "That IS consciousness."
The end point of this can only be one thing: The material brain itself IS conscious. It does not "create" some illusory, non-physical phenomenon we mistakenly call consciousness, rather consciousness IS the brain.
What most people claiming this don't understand is that this model perfectly describes a strain of panpsychism - that consciousness or mind is a fundamental feature of, not ALL things (general panpsychism), but rather, of the brain.
More on this later...
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Ed Hartouni
Trad climber
Livermore, CA
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Mar 23, 2017 - 10:15pm PT
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about thought experiments, and their "literary" aspects...
Up thread Paul complained (what's new) to my reference to "literary" phenomenon,
What's meant by "literary phenomenon" here is at best vague.
and it was, perhaps, vague. So I'll follow up on it, I think this makes an interesting story and along the lines of how what we consider "words" might have a meaning deeper than "just words," and here I mean a physical meaning.
In a letter to Peter Tait, James Maxwell proposed an interesting thought experiment that seemed to challenge the 2nd law of Thermodynamics:
"Now let A and B be two vessels divided by a diaphragm and let them contain elastic molecules in a state of agitation which strike each other and the sides.
"Let the number of particles be equal in A and B but let those in A have the greatest energy of motion. Then even if all the molecules in A have equal velocities, if oblique collisions occur between them their velocities will become unequal, and I have shown that there will be velocities of all magnitudes in A and the same in B, only the sum of the squares of the velocities is greater in A than in B.
"When a molecule is reflected from the fixed diaphragm CD no work is lost or gained.
"If the molecule instead of being reflected were allowed to go through a hole in CD no work would be lost or gained, only its energy would be transferred from the one vessel to the other.
"Now conceive a finite being who knows the paths and velocities of all the molecules by simple inspection but who can do no work except open and close a hole in the diaphragm by means of a slide without mass.
"Let him first observe the molecules in A and when he sees one coming the square of whose velocity is less than the mean sq. vel. of the molecules in B let him open the hole and let it go into B. Next let him watch for a molecule of B, the square of whose velocity is greater than the mean sq. vel. in A, and when it comes to the hole let him draw the slide and let it go into A, keeping the slide shut for other molecules.
"Then the number of molecules in A and B are the same as at first, but the energy in A is increased and that in B is diminished, that is, the hot system has got hotter and the cold colder and yet no work has been done, only the intelligence of a very observant and neat-fingered being has been employed.
"Or in short if heat is the motion of finite portions of matter and if we can apply tools to such portions of matter so as to deal with them separately, then we can take advantage of the different motion of different proportions to restore a uniformly hot system to unequal temperatures or to motions of large masses.
"Only we can't, not being clever enough."
(Maxwell, James Clerk. “Letter from Maxwell to Tait, Dec. 11, 1867.” In Life and Scientific Work of Peter Guthrie Tait, edited by Cargill Gilston Knott, 3:213-214. Cambridge: Cambridge University Press, 1911.)
This is the birth of Maxwell's Demon, and addressing this "thought experiment" was the work of physicists concerned with resolving the paradox, perhaps in the hope that such resolutions often lead to deeper insights.
But the presentation of the paradox is based on a literary figure, the "intelligent, observant and neat-fingered being."
Maxwell hated that Lord Kelvin, (William Thomson) gave this being the name "Maxwell's Demon" and so wrote, again to Tait...
"Concerning Demons.
"1. Who have them this name? Thomson.
"2. What were they by nature? Very small BUT lively beings incapable of doing work but able to open and shut valves which move without friction or inertia.
"3. What was their chief end? To show that the 2nd Law of Thermodynamics has only a statistical certainty.
"4. Is the production of the inequality of temperature their only occupation? No, for less intelligent demons can produce a difference in pressure as well as temperature by merely allowing all particles going in one direction while stopping all those going the other way. This reduces the demon to a valve. As such value him. Call him no more a demon but a valve like that of the hydraulic ram, suppose."
To deepen the literary assignment, Pynchon uses the the creation of a working "Maxwell's Demon" in his 1965 story The Crying of Lot 49.
So what are we to make of this thought experiment?
For one thing, entropy itself has a rather dicy provenance, just what is it? Can you touch it? and so on and so forth, but the basic can of worms opened by Maxwell was to establish if there really was a 2nd law of thermodynamics.
So people set to work describing the Demon... by 1929 Leó Szilárd nearly cracked the problem, noting that the thermodynamic system had to include the Demon, and that meant the computations the Demon did were also a part of the story. Interestingly, this direction skates out onto even thinner ice, by considering the "information entropy" (a creation of Shannon's which Von Neumann famously named, stating in response to Shannon's question about what the name should be "call it entropy, no one knows what that is.")
So the Demon keeps track of the the molecules
"Now conceive a finite being who knows the paths and velocities of all the molecules by simple inspection..."
but not so fast, the "simple inspection" involves processing information. In 1982 Bennet realized that the Demon eventually had to "erase" the prior information at some point, and erasing the information was thermodynamically irreversible, and would increase the entropy. Not only that, but the information would have to be erased at some point, storage capacity is finite.
The various bits of this part of the story were tested, experimentally, and reported in 2012:
http://www.nature.com/news/the-unavoidable-cost-of-computation-revealed-1.10186
(See the 2015 ArXiv paper for details.)
The important insight gained was in a 1961 paper by R. Landauer and Bennet expanded on the general importance by referring to the information content of DNA, which are affected by these information theory issues. "The enzymatic apparatus of DNA replication, transcription, and translation appear to be nature's closest approach to a Brownian computer, dissipating 20–100kT per step."
[It turns out that many of Rolf Landauer's ideas are being recognized as important in modern applications where understanding quantum fluctuations is of central importance.]
The amazing thing being, of course, that physical systems exploiting Demon-like properties demonstrate that "information" has thermodynamic content... that is, the information is physical.
http://www.nature.com/news/2010/101114/full/news.2010.606.html
But it turns out that, while the Classical version of the Demon died, there was the Quantum version, which Maxwell had no idea existed, but provides a tribute to the domain that Thermodynamics encompasses.
This was the subject of a recent paper in Physical Review Letters:
http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.117.240502
Experimental Rectification of Entropy Production by Maxwell’s Demon in a Quantum System
Patrice A. Camati, John P. S. Peterson, Tiago B. Batalhão, Kaonan Micadei, Alexandre M. Souza, Roberto S. Sarthour, Ivan S. Oliveira, and Roberto M. Serra
Phys. Rev. Lett. 117, 240502 – Published 5 December 2016
Abstract:
Maxwell’s demon explores the role of information in physical processes. Employing information about microscopic degrees of freedom, this “intelligent observer” is capable of compensating entropy production (or extracting work), apparently challenging the second law of thermodynamics. In a modern standpoint, it is regarded as a feedback control mechanism and the limits of thermodynamics are recast incorporating information-to-energy conversion. We derive a trade-off relation between information-theoretic quantities empowering the design of an efficient Maxwell’s demon in a quantum system. The demon is experimentally implemented as a spin-½ quantum memory that acquires information, and employs it to control the dynamics of another spin-½ system, through a natural interaction. Noise and imperfections in this protocol are investigated by the assessment of its effectiveness. This realization provides experimental evidence that the irreversibility in a nonequilibrium dynamics can be mitigated by assessing microscopic information and applying a feed-forward strategy at the quantum scale.
but see the commentary:
Viewpoint: Maxwell’s Demon Meets Nonequilibrium Quantum Thermodynamics
We could claim here that the "literary phenomenon" referred to as "Maxwell's Demon" was replaced by physical systems which acted in accordance with Maxwell's original idea, but the actual phenomenon didn't involve "the intelligence of a very observant and neat-fingered being."
While we might like to know a number of personal, human attributes of this being, and see that an actual being exists and performs the role described by Maxwell, it turns out "physical phenomenon" can be created that does this too.
The image of the Demon is enticing, but there is no Demon... there is an interesting lot of physics involved.
Hopefully you see the metaphoric meaning of my reference to consciousness as a "literary phenomenon." Perhaps it's a bit less vague.
If you focused on meeting the Demon, you'd be disappointed, but if you wanted to explain the related phenomenon, you're golden.
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MH2
Boulder climber
Andy Cairns
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Mar 24, 2017 - 08:17am PT
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Chalmers explicitly places consciousness outside the bounds of science, and probably of philosophy too:
“[We must] take consciousness seriously. … [To] redefine the problem as that of explaining how certain cognitive or behavioural functions are performed is unacceptable.”
That does create a Hard Problem.
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MH2
Boulder climber
Andy Cairns
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Mar 24, 2017 - 08:23am PT
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Amen
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MikeL
Social climber
Southern Arizona
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Mar 24, 2017 - 08:48am PT
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Ed:
Perhaps we should, for a few posts anyway, talk about the validity of “thought experiments” (Albert Einstein's notwithstanding). Why don’t we just call them imaginative narratives?
I (and some other folks) would say reality is what we imagine. Grasp that notion, even partially, and one might see more clearly.
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WBraun
climber
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Mar 24, 2017 - 09:03am PT
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The religious always seek to remove their province from earthly bounds.
This stoopid statement shows total poor fund of knowledge.
It's happening on this planet, therefore, the statement is false.
The gross material, the subtle material, and the superior spiritual energies are simultaneously working on this planet.
The foolish gross material mental speculators are just that!
They mental speculate and (make up sh!t) they know nothing about and label it religion, or whatever fits their crazy ideas in their dim heads.
Then they masquerade that as some kind of science knowledge.
Thus .... scientism is consistently displayed in full view and force by the foolish gross materialists and their daily mental speculations in their uncontrolled tiny fertile minds .......
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paul roehl
Boulder climber
california
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Mar 24, 2017 - 09:19am PT
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Chalmers explicitly places consciousness outside the bounds of science, and probably of philosophy too:
Of course the curious thing is that science and philosophy can exist only within the bounds of consciousness. Knowing can exist only within the bounds of consciousness and I'd say that makes, if you at all value knowing, consciousness a "crown of creation."
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Ed Hartouni
Trad climber
Livermore, CA
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Mar 24, 2017 - 09:38am PT
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Of course the curious thing is that science and philosophy can exist only within the bounds of consciousness. Knowing can exist only within the bounds of consciousness and I'd say that makes, if you at all value knowing, consciousness a "crown of creation."
to say this with any meaning implies you have a definition of consciousness and "knowing"... otherwise, you have a trivial statement which essentially defines consciousness arbitrarily.
what's your definition of consciousness?
what's your definition of knowing?
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Ed Hartouni
Trad climber
Livermore, CA
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Mar 24, 2017 - 10:06am PT
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Perhaps we should, for a few posts anyway, talk about the validity of “thought experiments” (Albert Einstein's notwithstanding). Why don’t we just call them imaginative narratives?
I (and some other folks) would say reality is what we imagine. Grasp that notion, even partially, and one might see more clearly.
maybe, but "the job" of a thought experiment isn't to apply unfettered imagination in an attempt to make it reality...
rather, thought experiments take a physical idea and pushes it to a logical conclusion based on what is known, often to reveal what is not known, or at the very least, the dependence on a particular physical assumption.
So when Maxwell was creating his "Demon" he wasn't creating just any "imaginative narrative" but one that fit the constraints of physical theory. Less imaginative, perhaps, was his later constraint that the Demon was "just a valve" and that the control of the valve has the contemporary instantiation as a "feedback" control. All physical realizations of Demons are just that...
What a physicist "imagines" is not just anything, but those things that are physical, and while many bemoan the constraint, it is what physicists do... Einstein is famously cited for his thought experiment: "what is it like to ride along with a light beam?" This can be more prosaically stated as a question regarding the validity of Galilean Relativity, for which the question has meaning (because in Galilean Relativity there is no constraint on velocity).
The constraint of Einstein's Special Relativity is not a lack of imagination, replacing the speed-limit-free Newtonian view of space and time with the constraint of light's speed. This constraint makes the question meaningless, it is not physically attainable for an object of finite mass. Just what a photon "sees" may be interesting... but prescribed by Maxwell... which is what led Einstein to Special Relativity.
But actually Special Relativity opens up an immense domain, and makes an important observation, that the "speed-of-light" has to do with the space-time geometry, and the "distance" between different points in that space-time... it fuses space and time together.
General Relativity also has its "thought experiments." The bending of light in a gravitational field being one of them... Einstein (or someone, but he is attributed to this idea) has us think of riding in an accelerating elevator. In the side wall a small port admits a beam of light, we watch where that light falls on the opposite side of the elevator, it is "below" the point we'd expect.
Now Einstein also pointed out that we cannot tell the difference between riding in that elevator, and being close to a large mass the produces the identical acceleration, there is no experiment we can do to tell the difference... therefore, gravity bends light.
In the summer of 1919, four years after the publication of General Relativity, Eddington adventured to the South Pacific to witness a total eclipse of the Sun, and measure the location of the field of stars near the Sun's occluded limb. He reported that the position of those stars changed, bent by the Sun's gravity in just the way Einstein's theory predicted.
Perhaps this is a victory for imagination...
Steve Weinberg spends Chapter 8 of his book Gravitation and Cosmology discussing "Classical Tests of Einstein's Theory" and a large part of that chapter on "The Deflection of Light by the Sun." This calculation is relegated to "exercise 7.3E in "The Telephone Book"...
By and large, the "thought experiment" gets all of the important points, except for the actual, quantitative prediction.
Most dreamers would object to the requirement that such "quantitative prediction" is a required result of their dreaming, not physicists.
What part does this quantitative prediction play in "imaginative narrative"? It plays a large role in mine...
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jgill
Boulder climber
The high prairie of southern Colorado
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Mar 24, 2017 - 12:24pm PT
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Nice post, Ed.
I (and some other folks) would say reality is what we imagine
Well, that's certainly one way to view reality, Mike. However, I can easily imagine riding to Mars on the back of a unicorn, but that's probably not going to happen. But thought experiments are intriguing.
Long-winded posts full of sound and fury, signifying nothing
And that's where a certain high school English teacher is pathetically wrong.
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paul roehl
Boulder climber
california
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Mar 24, 2017 - 12:38pm PT
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to say this with any meaning implies you have a definition of consciousness and "knowing"... otherwise, you have a trivial statement which essentially defines consciousness arbitrarily.
what's your definition of consciousness?
what's your definition of knowing?
Nonsense. "Knowing" can't exist without awareness. And though consciousness may be outside the purview of science and philosophy, science and philosophy (tools designed for acquiring "knowledge") require consciousness/awareness for their existence. How this implies knowing a specific definition of consciousness makes no sense. Too often you deal in solipsisms and semantics.
There are a variety of kinds of knowing (epistemologically) but they all boil down to awareness and certainty. What you know may be in error as certainty is not necessarily truth, but how we use the term "knowing" doesn't seem much of an issue. Consciousness, well that's a hard problem, but it certainly includes awareness of the self and the infinite loop of the self realizing itself.
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Largo
Sport climber
The Big Wide Open Face
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Topic Author's Reply - Mar 24, 2017 - 01:22pm PT
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Ed said: Hopefully you see the metaphoric meaning of my reference to consciousness as a "literary phenomenon."
The challenge with is that, as mentioned, literary metaphors are ways to widen the scope of exposition by contrasting this with that. But we can't use figurative language and logic with any precision per consciousness because "this" (consciousness) is not like "that" (the force or external object of your choice) in any way shape or form.
So I am unclear exactly what Ed means in his belief that consciousness is a literary phenomenon.
But rather than bicker over terms, I would simply ask Ed if he considers his own direct experience to be real - or not?
Ed asked Mike for a definition of consciousness and here is mine:
Consciousness is the immediate fact of experience, the capacity to have experience and the naturalistic process by which experience arises and falls away. Or in a word, consciousness IS experience.
In more functional terms, consciousness arises through the interface of mind (brain) generated content (thoughts, feelings, sensations and memories) and awareness. The three (mind, awareness and consciousness) comprise a unified whole.
That much said, we might ask Ed: Are you saying that you do NOT have an experience of thinking and seeing and writing on this thread?
Are you saying that you only imagine that you are having an experience, and that that "experience" is itself illusory?
If so - and this is vital to your case - explain to us how the previous is logically coherent. To do so you'll have to define the difference between imagining having an experience, and actually having an experience. That is, what criteria would have to be met for you to call your own experience (if indeed you have it) real?
The logical incoherence of such a line of reasoning (and I am NOT sure this is Ed's take on it) is accented by trying to contrast the difference between a computer and a sentient human being.
When Strong AI geeks talk about a future of conscious machines, what exactly will be the difference between the future rigs and present day computers, even supercomputers like Vulacn? Is it that future sentient machines will simply have the capacity of "imagining they have experience," whereas present day models cannot. And is this imagining unconscious? And what, exactly DOES this imagining.
If it's the brain that imagines, you are, as spelled out in my last post, left with a specific strain of panpsychism.
At bottom I think the part that Ed struggles with is the false belief that consciousness somehow exists as something other than a component of a unified whole. But so long as he is in so many ways believing that consciousness is itself a physical phenomenon, he is right there with Whitehead with his panpsychism.
The implications of this are vast.
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jgill
Boulder climber
The high prairie of southern Colorado
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Mar 24, 2017 - 01:44pm PT
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Consciousness is the immediate fact of experience, the capacity to have experience and the naturalistic process by which experience arises and falls away. Or in a word, consciousness IS experience
What is "experience"? This is an example of the game of musical chairs philosophers love. You can't define one thing? Well relate it to something else that can't be defined accurately. How about "awareness"? is awareness the same as consciousness? If it is, then can one have "empty experience"? On and on . . .
Perhaps we'd be better off if there were NO word for what we consider "consciousness". Thousands of pages of philosophical convolutions would then vanish, with hardly a notice in the world in which we live.
The implications of this are vast
To some, perhaps.
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jgill
Boulder climber
The high prairie of southern Colorado
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Mar 24, 2017 - 01:48pm PT
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But it was interesting to see that a map of a country will have a corresponding point in that country, if you lie the map flat on a table anywhere within the country
This made me think of the simple scaling I perform in computer graphics. If
z=x+iy or (x,y) is a point on the screen, then the point (0,0) is the upper left hand corner of the screen, with increasing x to the right and increasing y downward. Accordingly to shift (0,0) to the center of my screen (600,350), to then scale the dimensions by a factor S, and to have increasing x to the right and increasing y upward, I use
u(x)= 600+Sx and v(y)=350-Sy.
If in addition I want place a new center (a,b) for some graphics display in the center of my computer screen, I use
u(x)=600+S(x-a) and v(y)=350 +S(b-y)
Then a fixed point would be u(x)=x and v(y)=y. For example, suppose the scale is S=50 and the center point of my screen should be (100,50). I find that the unique fixed point under this transformation is approximately (89.8,55.9).
I know, more hopeless blathering from a labcoat.
deal with it.
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