Consciousness and Downward Causation

For many people, the phenomenon of consciousness is the best evidence we have that there must be something important missing in our basic physical description of the world. According to this worry, a bunch of atoms and particles, mindlessly obeying the laws of physics, can’t actually experience the way a conscious creature does. There’s no such thing as “what it is to be like” a collection of purely physical atoms; it would lack qualia, the irreducibly subjective components of our experience of the world. One argument for this conclusion is that we can conceive of collections of atoms that behave physically in exactly the same way as ordinary humans, but don’t have those inner experiences — philosophical zombies. (If you think about it carefully, I would claim, you would realize that zombies are harder to conceive of than you might originally have guessed — but that’s an argument for another time.)

The folks who find this line of reasoning compelling are not necessarily traditional Cartesian dualists who think that there is an immaterial soul distinct from the body. On the contrary, they often appreciate the arguments against “substance dualism,” and have a high degree of respect for the laws of physics (which don’t seem to need or provide evidence for any non-physical influences on our atoms). But still, they insist, there’s no way to just throw a bunch of mindless physical matter together and expect it to experience true consciousness.

People who want to dance this tricky two-step — respect for the laws of physics, but an insistence that consciousness can’t reduce to the physical — are forced to face up to a certain problem, which we might call the causal box argument. It goes like this. (Feel free to replace “physical particles” with “quantum fields” if you want to be fastidious.)

  1. Consciousness cannot be accounted for by physical particles obeying mindless equations.
  2. Human beings seem to be made up — even if not exclusively — of physical particles.
  3. To the best of our knowledge, those particles obey mindless equations, without exception.
  4. Therefore, consciousness does not exist.

Nobody actually believes this argument, let us hasten to add — they typically just deny one of the premises.

But there is a tiny sliver of wiggle room that might allow us to salvage something special about consciousness without giving up on the laws of physics — the concept of downward causation. Here we’re invoking the idea that there are different levels at which we can describe reality, as I discussed in The Big Picture at great length. We say that “higher” (more coarse-grained) levels are emergent, but that word means different things to different people. So-called “weak” emergence just says the obvious thing, that higher-level notions like the fluidity or solidity of a material substance emerge out of the properties of its microscopic constituents. In principle, if not in practice, the microscopic description is absolutely complete and comprehensive. A “strong” form of emergence would suggest that something truly new comes into being at the higher levels, something that just isn’t there in the microscopic description.

Downward causation is one manifestation of this strong-emergentist attitude. It’s the idea that what happens at lower levels can be directly influenced (causally acted upon) by what is happening at the higher levels. The idea, in other words, that you can’t really understand the microscopic behavior without knowing something about the macroscopic.

There is no reason to think that anything like downward causation really happens in the world, at least not down to the level of particles and forces. While I was writing The Big Picture, I grumbled on Twitter about how people kept talking about it but how I didn’t want to discuss it in the book; naturally, I was hectored into writing something about it.

But you can see why the concept of downward causation might be attractive to someone who doesn’t think that consciousness can be accounted for by the fields and equations of the Core Theory. Sure, the idea would be, maybe electrons and nuclei act according to the laws of physics, but those laws need to include feedback from higher levels onto that microscopic behavior — including whether or not those particles are part of a conscious creature. In that way, consciousness can play a decisive, causal role in the universe, without actually violating any physical laws.

One person who thinks that way is John Searle, the extremely distinguished philosopher from Berkeley (and originator of the Chinese Room argument). I recently received an email from Henrik Røed Sherling, who took a class with Searle and came across this very issue. He sent me this email, which he was kind enough to allow me to reproduce here:

Hi Professor Carroll,

I read your book and was at the same time awestruck and angered, because I thought your entire section on the mind was both well-written and awfully wrong — until I started thinking about it, that is. Now I genuinely don’t know what to think anymore, but I’m trying to work through it by writing a paper on the topic.

I took Philosophy of Mind with John Searle last semester at UC Berkeley. He convinced me of a lot of ideas of which your book has now disabused me. But despite your occasionally effective jabs at Searle, you never explicitly refute his own theory of the mind, Biological Naturalism. I want to do that, using an argument from your book, but I first need to make sure that I properly understand it.

Searle says this of consciousness: it is caused by neuronal processes and realized in neuronal systems, but is not ontologically reducible to these; consciousness is not just a word we have for something else that is more fundamental. He uses the following analogy to visualize his description: consciousness is to the mind like fluidity is to water. It’s a higher-level feature caused by lower-level features and realized in a system of said lower-level features. Of course, for his version of consciousness to escape the charge of epiphenomenalism, he needs the higher-level feature in this analogy to act causally on the lower-level features — he needs downward causation. In typical fashion he says that “no one in their right mind” can say that solidity does not act causally when a hammer strikes a nail, but it appears to me that this is what you are saying.

So to my questions. Is it right to say that your argument against the existence of downward causation boils down to the incompatible vocabularies of lower-level and higher-level theories? I.e. that there is no such thing as a gluon in Fluid Dynamics, nor anything such as a fluid in the Standard Model, so a cause in one theory cannot have an effect in the other simply because causes and effects are different things in the different theories; gluons don’t affect fluidity, temperaturs and pressures do; fluids don’t affect gluons, quarks and fields do. If I have understood you right, then there couldn’t be any upward causation either. In which case Searle’s theory is not only epiphenomenal, it’s plain inaccurate from the get-go; he wants consciousness to both be a higher-level feature of neuronal processes and to be caused by them. Did I get this right?

Best regards,
Henrik Røed Sherling

Here was my reply:

Dear Henrik–

Thanks for writing. Genuinely not knowing what to think is always an acceptable stance!

I think your summary of my views are pretty accurate. As I say on p. 375, poetic naturalists tend not to be impressed by downward causation, but not by upward causation either! At least, not if your theory of each individual level is complete and consistent.

Part of the issue is, as often happens, an inconsistent use of a natural-language word, in this case “cause.” The kinds of dynamical, explain-this-occurrence causes that we’re talking about here are a different beast than inter-level implications (that one might be tempted to sloppily refer to as “causes”). Features of a lower level, like conservation of energy, can certainly imply or entail features of higher-level descriptions; and indeed the converse is also possible. But saying that such implications are “causes” is to mean something completely different than when we say “swinging my elbow caused the glass of wine to fall to the floor.”

So, I like to think I’m in my right mind, and I’m happy to admit that solidity acts causally when a hammer strikes a nail. But I don’t describe that nail as a collection of particles obeying the Core Theory *and* additionally as a solid object that a hammer can hit; we should use one language or the other. At the level of elementary particles, there’s no such concept as “solidity,” and it doesn’t act causally.

To be perfectly careful — all this is how we currently see things according to modern physics. An electron responds to the other fields precisely at its location, in quantitatively well-understood ways that make no reference to whether it’s in a nail, in a brain, or in interstellar space. We can of course imagine that this understanding is wrong, and that future investigations will reveal the electron really does care about those things. That would be the greatest discovery in physics since quantum mechanics itself, perhaps of all time; but I’m not holding my breath.

I really do think that enormous confusion is caused in many areas — not just consciousness, but free will and even more purely physical phenomena — by the simple mistake of starting sentences in one language or layer of description (“I thought about summoning up the will power to resist that extra slice of pizza…”) but then ending them in a completely different vocabulary (“… but my atoms obeyed the laws of the Standard Model, so what could I do?”) The dynamical rules of the Core Theory aren’t just vague suggestions; they are absolutely precise statements about how the quantum fields making up you and me behave under any circumstances (within the “everyday life” domain of validity). And those rules say that the behavior of, say, an electron is determined by the local values of other quantum fields at the position of the electron — and by nothing else. (That’s “locality” or “microcausality” in quantum field theory.) In particular, as long as the quantum fields at the precise position of the electron are the same, the larger context in which it is embedded is utterly irrelevant.

It’s possible that the real world is different, and there is such inter-level feedback. That’s an experimentally testable question! As I mentioned to Henrik, it would be the greatest scientific discovery of our lifetimes. And there’s basically no evidence that it’s true. But it’s possible.

So I don’t think downward causation is of any help to attempts to free the phenomenon of consciousness from arising in a completely conventional way from the collective behavior of microscopic physical constituents of matter. We’re allowed to talk about consciousness as a real, causally efficacious phenomenon — as long as we stick to the appropriate human-scale level of description. But electrons get along just fine without it.

421 Comments

421 thoughts on “Consciousness and Downward Causation”

  1. James Cross:

    You wrote: “It is an objectively observable and independently verifiable (through multiple different approaches) fact that, within certain well-defined limits, all humans perceive color the same way. ”

    That’s clearly not correct since there are significant numbers of people with red-green color blindness, others with yellow-blue blindness, and some people with no color perception whatsoever.

    I would have thought that color blindness would be a blindingly (excuse me) obvious example of a well-defined limit.

    Apart from that, even for people with normal vision, we have no way to know they are perceiving color the same way just because they can differentiate colors the same. You can’t know what my “red” looks like.

    On the contrary. We can know it the exact same way that we know anything else: we make comparisons and check for agreement. Presumably, we both agree that the Sun appears to rise in the East and set in the West (but only almost exactly so on the equinoxes); that the Earth is actually (approximately) an oblate spheroid in an elliptical orbit about the barycenter of (roughly speaking) the Earth-Sun system; and that the clear daytime sky is (typically) blue.

    And when we ask each other what colors we see, no matter the language, with ludicrous types of precision for these sorts of things, we agree that we’re seeing the same thing.

    What you propose is no different from suggesting that, though we both say we’re seeing the Sun rise in the East, maybe for me it actually rises in the North and for you it simply pops into existence directly below, and it’s a bizarre coincidence that we just happen to use the same language in such a consistent manner.

    So quite literally two people could actually have completely upside down views of the world and still function normally and we would never suspect any difference in their subjective view of the world.

    But we’re talking about subjective perception, right?

    After the person has adapted to the upside-down flip, she subjectively perceives the sky above and the Earth below, correct? Despite it being objectively flipped, no? Which is the same as you perceive it without being flipped, right?

    If that isn’t a slam-dunk demonstration of the constancy of perception across individuals, what on Earth possibly could be?

    Cheers,

    b&

  2. Logicophilosophicus:

    He complained that Cantor could never show anyone a completed infinite set, or point at an infinitesimal point, yet his proofs relied on these entities.

    And yet physicists and engineers and all the rest casually sum infinities and infinitesimals all day long in their day jobs, getting real work done. I hope you’ll forgive me if I remain spectacularly unimpressed by philosophical objections along such lines.

    For anyone interested, the side issue (Dawkins’s argument) is simply this. Dawkins claimed that anything which could create the complex (especially living) world we observe would have to be more complex; if that had been true, then it would also be true of the creator, etc…

    You have spectacularly missed the whole point of Richard’s discourse. It is creationists who claim that complexity such as life can only come from an intelligent designer. It should be obvious why such intelligence must be even more complex than what it’s designing…were it simpler, there’d be no need to invoke it in the first place, since nature and Evolution meet that requirement. All Richard does from there is note that, if something merely as complex as life requires an even-more-complex designer, then that even-more-complex designer needs one, as well — thus demonstrating the absurdity of the creationist argument.

    It should be equally obvious that all “ultimately fundamental” arguments of any type are equally fallacious, including your own. Whatever reason you care to propose for why something is necessary is going to apply equally well to your answer, and to the answer’s answer, and so on.

    And, if you’re as familiar with the Halting Problem as your extensive namedropping would indicate, it should be every bit as obvious that it’s just another variation on the same thing. If you could create a program that would determine if another would halt, you could feed it to itself in a way guaranteed to confound it; ergo, no such program exists. Equally, no such fundamental reality exists of any nature — just swap out the terms.

    Cheers,

    b&

  3. John

    I would lengthen it a bit.

    “The speed of light (in a vacuum) is a universal constant which is a central postulate of the well-tested theory of relativity , and there is no reason or evidence to assume otherwise.”

  4. John

    You seem to have a sincere interest in understanding relativity. It is a worthy pursuit. May I suggest a great book to you. Relativity Visualized by Lewis Carroll Epstein. It is out of print but you can get it if you look around online. If you work your way through this book (almost no math) you can attain a deep intuitive grasp of relativity. I have a degree in physics but I have read it twice with excellent results.

    I hope Sean does not mind my recommending another book on his blog. But if you read Epstein’s book, you can get even more value out of Sean’s.

  5. Ben,

    Obviously it is a waste of time for me to say anything to you, so just google “speed of light in a VACUUM!”

    Neil,

    And suspect that book too will not explain why they cut and pasted the idea of “spacetime!” to explain redshift and totally ignored the very obvious fact that light speed isn’t remaining CONSTANT TO THE DISTANCE!!!!!

  6. Logicophilosophicus

    Ben G

    Logicophilosophicus:

    “…physicists and engineers and all the rest casually sum infinities and infinitesimals all day long in their day jobs, getting real work done. I hope you’ll forgive me if I remain spectacularly unimpressed by philosophical objections along such lines.” SHOW ME ONE example of a physicist or engineer summming infinities “getting real work done.”

    “It is creationists who claim that complexity such as life can only come from an intelligent designer. It should be obvious why such intelligence must be even more complex than what it’s designing…were it simpler, there’d be no need to invoke it in the first place, since nature and Evolution meet that requirement.” Where to start. An organism is less complex – has lower entropy – than a random arrangement of the same bundle of atoms. Design and complexity are two different things. We are familiar with design because we are designers. Design, like consciousness, is a problem: where does it come from? (Dawkins of course says organisms are “designoid”, which is only defined by analogy with “design”, which therefore exists…) Anyway, you and Dawkins think it “obvious” that a designer must be more complex than its product. To me that’s about as obvious as the idea that a family of three children must have more than three parents, or that a diamond drill tip must be more complex than the detritus it produces. Or that a collapsing cloud of hydrogen and helium must be more complex than the ensuing first and second generations of stars with their diverse planets and comets. Complexity inevitably increases because entropy, which is the negative of order, increases. Organisation, which always involves order, necessarily decreases.

    “It should be equally obvious that all ‘ultimately fundamental’ arguments of any type are equally fallacious, including your own. Whatever reason you care to propose for why something is necessary is going to apply equally well to your answer, and to the answer’s answer, and so on.” Again, that’s about as obvious to me as claiming that since Dickens wrote Oliver Twist, somebody must have written Dickens – but I already said that: a sequence of natural numbers does not imply that there are natural numbers smaller than unity.

    “And, if you’re as familiar with the Halting Problem as your extensive namedropping would indicate, it should be every bit as obvious that it’s just another variation on the same thing. If you could create a program that would determine if another would halt, you could feed it to itself in a way guaranteed to confound it; ergo, no such program exists. Equally, no such fundamental reality exists of any nature — just swap out the terms.” In Littlewood’s “A Mathematician’s Miscellany” he describes how he requested a footnote to a French edition of one of his booksalong the lines of “My thanks to Monsieur for translating this book,” (in French, of course). Being a pedantic mathematician, Littlewood insisted on the addition of a second footnote thanking the translator for translating the first footnote – which was (being pedantic) not part of the original book. It was pointed out to him that this would require a third, fourth, etc footnotes, ad infinitum. Not so, Littlewood replied. He might not be capable of writing a footnote in French, but he was obviously capable of copying one, which made such footnotes unnecessary after all. In terms of the universe, Spinoza would say it was (in its godlike function) causa sui”, needing no further explanation.
    Name dropping. I like to give credit to the source of my ideas (and of the ideas I criticise) – sources I have studied, read, understood. Name dropping is the name without the idea, or the understanding, like the girl who “danced with a man who danced with a girl who danced with the Prince of Wales.”

  7. Logicophilosophicus

    Ben G

    Of course if I am wrong about name dropping I will apologise:

    “…we now know how to deal with infinities, and sound logic demonstrates that the initial premise, that there’s always some sort of a singular explanation underlying everything, is invalid. Instead, there may or may not be such explanations, and there is no way to know “from the inside” whether or not you’ve arrived at such. That’s what lies at the heart of the famous works of Cantor and Turing and Gödel — and it applies just as well to the Universe as an whole as it does to the countability of real numbers.”

    The only thing C, T and G have in common is diagonalization in mathematics and logic, and it has nothing to do with physical reality. (In any case, unfortunately, all that diagonalization hopes to prove is that the real numbers cannot be systematically listed by constructing a real number which cannot be on the list. Show me one.) I

  8. John Merryman,

    “And suspect that book too will not explain why they cut and pasted the idea of “spacetime!” to explain redshift and totally ignored the very obvious fact that light speed isn’t remaining CONSTANT TO THE DISTANCE!!!!!”

    You are still missing the most basic thing. Redshift has zero to do with distance, or how much space has grown or shrunk. It has only to do with the relative velocity of two objects that are passing light between them. This is relative velocity to each other, not relative to the speed of light.

    The redshift only tells you how fast things are moving away from you. That’s all.

    Looking around the universe, it appears that the furthest objects have the most redshifted light, so they are moving away the fastest.

    So the hypothesis is that this is because the universe is expanding, that more space exists now than in the past. This explains how everything could be moving away from us at vast speeds.

    There are other alternative ways to explain it that are equally valid. You could say that the same amount of space exists (perhaps it is infinite), but the objects are just rapidly moving apart into space that previously had nothing in it, so there is an edge to where stuff exists, outside of which is just empty space. Most people think that does not sound as reasonable to them as the universe expanding.

  9. Moe,

    “There are other alternative ways to explain it that are equally valid.”

    Okay, now that I thought about it, my extra example couldn’t actually be true, without adding a lot of extra conditions.

    Just try to think of it from the standpoint of a photon moving at light speed, and thinknof that photon not as a thing, but a transfer of energy.

    Think about light cones. Lines along these are the shortest distances through spacetime, and could be called ‘direct interaction distance’.

  10. Moe,
    I assume you understand that relativity is based on the fact that in frames moving relative to the vacuum, both the measured speed of light and length of mass objects shrink proportionally, consequently the speed of light between points in that frame still measure as C. When it gets to light speed, there is no motion or activity, so time is zero. That is why light is such a good carrier of information.

    So if you are going to turn around and say, “Space expands, because SPACETIME!” Why wouldn’t it be a requirement that the speed of light INCREASE, in order to remain CONSTANT?

    Obviously it does not, as the whole premise is that it is because the light takes longer to cross this distance, as these points move apart, the effect is doppler shift. The spectrum is redshifted to the observer, as the waves have more space to cross.

    Yet if the light is taking longer to cross, then it is not constant to the distance, but some underlaying “vacuum.”
    Now if there is some underlaying vacuum that is so foundational to our reality ,that it is the frame on which C is based and it doesn’t expand with he universe, then the universe must be expanding within this larger frame. In which case, we get back to the problem of why we appear as the center of the universe.

    All of which is based on the certain knowledge that we know the only reason light can be redshifted over billions of years, is due to actual doppler shift. While googling “vacuum” for Ben, who seems incapable of understanding the term, I came across this;
    http://www.iflscience.com/physics/speed-light-can-vary-vacuum/
    So how much do we really, fully understand what light will do? As it is, inflation and Dark Energy are two enormous patches that have been added to sustain the theory.
    How far out on a limb does it go?

  11. John Merryman,

    “I assume you understand that relativity is based on the fact that in frames moving relative to the vacuum”

    I think that this is your problem. This is 100% false.

    Speeds are never measured relative to the vacuum. This absolutely can not be done. This was shown by 19th century experiments that led to the discovery of Special Relativity. This is the entire point of Special Relativity.

  12. “On the contrary. We can know it the exact same way that we know anything else: we make comparisons and check for agreement. Presumably, we both agree that the Sun appears to rise in the East and set in the West (but only almost exactly so on the equinoxes); that the Earth is actually (approximately) an oblate spheroid in an elliptical orbit about the barycenter of (roughly speaking) the Earth-Sun system; and that the clear daytime sky is (typically) blue.”

    LOL

  13. This all makes me think that classical models cannot completely accurately describe peoples actions alone or ever will, really. If you consider the fact that quantum mechanics cannot be combined with existing classical or large scale theories and then consider the possibility that these theories are truly incompatible on a fundamental level, then it would mean that any large scale theory wouldn’t be able to accurately describe peoples actions on their own. All of the craziness and weirdness of quantum mechanics could then leak into the theory and throw it off. Then there wouldn’t exist any casual or classical explanation that describes what happens in the brain and proceeds to describe our own actions. You could have really ate that pizza, because your x-girlfriend was thinking about the time you ate pizza with her together 15 years ago. It may not have required any extra energy in order for you to make that decision, and you picked up on that stray photon finally. Then you would have gained a lot more energy in the process of actually eating it, and then in that regime, a large scale theory would begin to become more accurate.

  14. Moe:

    John Merryman,

    “I assume you understand that relativity is based on the fact that in frames moving relative to the vacuum”

    I think that this is your problem. This is 100% false.

    Speeds are never measured relative to the vacuum. This absolutely can not be done. This was shown by 19th century experiments that led to the discovery of Special Relativity. This is the entire point of Special Relativity.

    Yes — the Michelson-Morley experiment I keep mentioning.

    John, you are correct that the value for the speed of light that is given as the standard is its speed in a vacuum. But that most emphatically does not mean that it’s somehow measured “against” the vacuum! Indeed, the very idea of measuring something against nothing is meaningless.

    The reason why the “in a vacuum” bit is always included is that, whenever light has to travel through something, it, poetically, stumbles and gets tangled up, causing it to slow down. Different substances slow it down differently. And, when it slows down, it refracts — just as any wave would. Air slows it down a little, but water slows it down a lot, which is why a straight straw looks bent when you put it in your half-full glass. Diamonds slow it down more than most anything else, causing their dazzling sparkle of rainbow colors.

    So, it’s not that light is somehow being measured against a vacuum. Rather, we’re interested in, if you will, “uncontaminated” light — light going through nothing whatsoever…the empty void, the nothingness that we refer to as “the vacuum.”

    And since light in a vacuum is traveling through nothing, there’s nothing there for it to propagate through…and nothing to measure it against.

    …hope this breaks loose some sort of logjam….

    Cheers,

    b&

  15. Logicophilosophicus:

    SHOW ME ONE example of a physicist or engineer summming infinities “getting real work done.”

    <sigh />

    Every single time they use The Calculus to do something like…you know? Sum the area under a curve?

    In terms of the universe, Spinoza would say it was (in its godlike function) causa sui”, needing no further explanation.

    But that’s either (take your pick) special pleading or an invalidation of your initial premise.

    If the Universe needs no further explanation,then we know that it is not true that everything needs an explanation; instead, we first must establish that which does and doesn’t need explanation. Indeed, “explanation” in this context is coherent only within a framework such as Aristotelian Metaphysics which, though perhaps notable for its age, today is nothing more than primitive superstition. Newton most emphatically established that there’s no Mover that Moves things in motion; inertia is why they keep moving, and “inertia” is simply our language for the observation that that’s what things do.

    But, again, if you’re going to continue to insist that we must explain everything in such Aristotelian terms, you can’t then turn around and pick and choose exceptions.

    Cheers,

    b&

  16. Logicophilosophicus:

    The only thing C, T and G have in common is diagonalization in mathematics and logic, and it has nothing to do with physical reality.

    Yes, exactly.

    And my point is that you can use diagonalization to demonstrate that there are more sets of possible conspiracy theories than there are actual realities.

    b&

  17. “The reason why the “in a vacuum” bit is always included is that, whenever light has to travel through something, it, poetically, stumbles and gets tangled up, causing it to slow down.”

    Light can be manipulated so that its speed is less than c in a vacuum too, which is shown in the interesting article John Merryman linked. But the speed of such structured light is not relevant to relativity. c is the upper limit for the speed of light in vacuo and is the same for all observers regardless of their relative motion.

  18. Moe,
    “Speeds are never measured relative to the vacuum. This absolutely can not be done. This was shown by 19th century experiments that led to the discovery of Special Relativity. This is the entire point of Special Relativity.”

    What MM showed is that there is no medium through which light travels as a wave. Aka, the aether.

    Now Relativity’s explanation of MM was that light is always measured at C, because the frame is compressed. At the speed of light, it is frozen. Not that here is no effect!

    Do we agree that at the speed of light, time has stopped, because no additional motion, i.e. change, is possible? That is a very serious effect. What is it relative to, if not some equilibrium state?

    In a frame traveling some fraction of the speed of light, both distance is compressed and light has slowed so that light is still measured at C.

    Presumably there is some way to measure which frames have faster clocks and longer distances.

    So if you place lots of different frames around and find the one with the fastest clocks and least compressed distances. Wouldn’t that frame be the one closest to the equilibrium of space?

    So it would seem, to me at least, that the vacuum is a state of equilibrium. Which also goes to vacuum fluctuation as a disturbance of that equilibrium.

    Now I realize you are all really going to wig out over this, but it does seem there is an equilibrium implicit to the vacuum.

    (Not a medium, Ben. A vacuum. Complicated, I know. Aether is a medium. Equilibrium is balance.)

  19. James, if you don’t agree with me that the Sun rises in the East, that the Earth is round, and the sky is blue, then not only do we have no common frame of reference with which to have a discussion…but at least one of us is desperately deluded and in need of professional mental health treatment.

    But, if, as I would hope, you do agree with me, then you’ve got no reason to disagree with me with respect to color perception.

    b&

  20. John:

    In a frame traveling some fraction of the speed of light, both distance is compressed and light has slowed so that light is still measured at C.

    No. You’re still thinking in terms of a medium, no matter how much you insist you’re not.

    Light doesn’t slow.

    (With the notable exception of when it’s traveling through not-vacuum such as air or diamond.)

    So if you place lots of different frames around and find the one with the fastest clocks and least compressed distances. Wouldn’t that frame be the one closest to the equilibrium of space?

    Nope. Were space a medium, yes, of course — but it’s not.

    You’re looking for an absolute fixed background against which all else is measured. That’s exactly what a medium is. That’s exactly what doesn’t exist.

    Cheers,

    b&

  21. John Merryman,

    “Presumably there is some way to measure which frames have faster clocks and longer distances.”

    No, there is absolutely not any way to do this.

  22. Ok, I’ll probably have to go back and read up on this. Been a few decades. A point or two;

    Consider the premise of vacuum fluctuation; If you have positive and negative charges popping into and out of existence, that would seem to imply equilibrium. As in +1 and -1 would seem to imply a 0.
    Equilibrium/0 is not a medium. The fluctuation, the +1 and the -1 would be a medium.

    If light traveled at C in any old frame and two frames traveled through each other, going in opposite directions, why wouldn’t their light appear as faster than C, in the opposing frame, if there is no universal frame?

    As I learned it, way back in the 70’s, the reason space and time are compressed in a moving frame is that because nothing can go faster than C, the speed of the frame is subtracted from any internal motion, because if it wasn’t, then the motion of the frame and the internal motion would add up to more than C. Since any physical object is made up of atomic structure, it would be slowed and thus compressed as well. Which would seem to imply a larger, universal frame=0.
    As for treating this as a medium, I don’t see why. Light would be the most essential medium itself. E=mc2.

    Now I suppose we agree that at C, all motion within the frame has stopped, thus no time and the information being carried by this light is undisturbed. Yet that light can travel across the universe, so it would seem the universe is a frame and any sub frame within it is defined by the speed being slower.

    Off to work….

  23. John Merryman,

    “Ok, I’ll probably have to go back and read up on this. Been a few decades.”

    I think that would be a good idea for you to do.

  24. Moe,
    (back for breakfast)
    I am not a professional, so I have the option of not having to pass judgement, though as I see it, the current theory is overly patched together. As even Paul Steinhardt says, inflation creates more problems than it solves. Ben likes to say I treat an equilibrium state as a medium, but simply saying the overall frame can expand faster than the speed of light, just to explain why the CMBR is uniform would seem to be treating it as a similar medium.
    If redshift is an optical effect, the cosmological principle, of overall uniformity, would explain why this radiation is so smooth, being the light of infinite sources, shifted down the spectrum.
    It also does not answer my original issue, of how one measure of space/vacuum is being derived from the redshifted spectrum of intergalactic light and then compared to another measure, based on the speed of the very same light.
    I suspect Big Bang theory will eventually go the way string theory appears to be going. A useful intellectual exercise, but overlooking deeper issues in the rush to completion.
    http://www.americanscientist.org/issues/pub/2007/9/modern-cosmology-science-or-folktale

  25. John Merryman,

    As I stated early in the discussion of this post, I believe in the eternal block idea of the universe, in a many worlds way. Every possibility that could exist (within certain ‘rules’ or ‘laws’) actually does and is. What we call time and space emerge from this.

    So, I will not argue with you about the big bang being an actual big bang at a point in time.

    But, if we want to discuss things in the standard terminology (which is valid in our common limited point of view) then you are definitely misunderstanding how other people are measuring things and interpreting the results that are obtained.

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