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.)
- Consciousness cannot be accounted for by physical particles obeying mindless equations.
- Human beings seem to be made up — even if not exclusively — of physical particles.
- To the best of our knowledge, those particles obey mindless equations, without exception.
- 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.
John:
(First, please forgive the selective response…pressed for time, so I’m just cherry-picking the low-hanging fruit.)
This is a very common misconception, understandably so, but one that has far-reaching and profound implications for widespread confusion.
Yes, we naturally associate low entropy with high order. In our daily lives, we think of a messy room as having high entropy and the nice and neat and ordered room as having low entropy.
But entropy and order / complexity / structure / whatever are not correlated in any absolute sense. There are probably some generalizable observations waiting to be made about their interrelationships, but certainly not the ones most people presume.
Consider Sean’s favorite example of a cup of coffee with cream. The low-entropy state is very orderly and simple: coffee on the bottom, cream on top. But the high-entropy state is even simpler: creamy coffee everywhere. Typically, all the interesting and complex stuff happens in the mixing, when you get the whorls and vortices and fractal stuff…but not necessarily. It is entirely possible for the two to instead slowly diffuse, with the intermediate phases being described as a gradual blending transition.
So, if you make any assumptions about the complexity or orderliness of a system based upon its entropy, you’re pretty much guaranteed to come to some incorrect conclusions. And, if you examine the conclusions you make from your own such assumption, you’ll see that our disagreements can in no small part be traced back to this assumption.
We don’t know yet if space is finite or infinite. And we already empirically know that “equilibrium” is a very precarious concept, with Heisenberg demonstrating that, at small scales, all is (at least random-seeming) chaos seething with uncertainty. The vacuum, even utterly devoid of matter and energy, still has all sorts of stuff happening. It’s a very paradoxical conundrum, how true nothing can still be full of something even while there really isn’t anything there…but keep in mind that our brains are evolutionarily honed to survive in the macroscopic world, and we should be surprised if phenomena at other scales in other environments made intuitive sense.
No; that’s just the extreme bookend. But long before the CMBR was discovered, Edwin Hubble famously observed inflation, and the constant (~70 km/s per megaparsec) still bears his name. Recreating Hubble’s observation is well within reach of modern amateur astronomers and is trivially reconfirmed with practically every professional deep-sky observation.
There was also an inflationary epoch in the early microseconds of the history of the Universe, when the rate of inflation was dramatically greater than at any other time. Current physics can explain this epoch, in the same terms as Hubble’s expansion; however, physics breaks down just before this period of hyperinflation.
You would seem to be behind the times on this.
Some time ago, astronomers calculated the mass of galaxies based on their optical observations. We know (roughly) how much stars weigh, and there are ways of (approximately) counting stars in galaxies. And we can observe the rotation of the galaxies (using spectroscopy, since they move far too slowly to watch in real time). The problem was that the only way the rotations made sense was if there was a lot more mass in the galaxies than we could account for. So, dark matter was proposed as a solution: in addition to all the matter we could see, maybe there was more matter we couldn’t see.
There were initial problems with the idea…namely, that nobody could come up with a reasonable proposal for what sort of matter could hide like that. Dust is the obvious naïve suggestion, but we’ve become very good at photographing galactic dust; it’s what makes up the dramatic dark bands of the best Hubble images of galaxies, for example. And we’ve learned a lot more about matter distributions of star systems, and so on…but it still didn’t add up.
Until recently.
NASA or ESA or somebody has been able to directly measure the mass of galaxies by means of gravitational lensing. I don’t have time for the details here and now, but it’s possible to directly map the amount and distribution of mass of a galaxy, entirely independent of its optical properties. And this technique shows two striking facts: there really is exactly as much mass as is necessary to account for the motions of the galaxies, and the mass is only roughly aligned with the bright stars. So we now know, without a doubt, that there really is a bunch of actual, real, honest-to-goodness “stuff” that’s found in and around galaxies that accounts for the missing matter…
…but we still don’t know what the “stuff” actually is.
Popular guesses are some exotic supersymmetric particle that the LHC may yet make, or primordial black holes, or we-don’t-know-what. But there’s no longer any question as to whether or not it’s there.
This is actually Sean’s current area of research. Rather than trying to quantize gravity, he’s trying to gravitize Quantum Mechanics. He’s probably bet you a cup of coffee / mug of beer / whatever that gravity and space emerge from quantum entanglement.
It was an interesting idea of his, but not particularly well supported by evidence at the time he proposed it. Since then, the fossil record has since been much, much, much better fleshed out, and we know that it really doesn’t describe biological evolution after all.
Whether or not it might serve as an useful analogy for academia…I’m again not sure. If you look at the grand arc of science, two facets stand out to me.
First is the acceleration. Aristotle to Newton took a very long time. Newton to Laplace was also a fair stretch. Laplace to Einstein wasn’t so long. Einstein and Schrödinger and Dirac were contemporaries. Peter Higgs was a child when that lot were getting their Nobel prizes, and not only did he live to see the LHC produce his Boson, he’s still going strong today.
Second is the way everything “reduces down” to the old stuff. I often dismiss Aristotle as primitive superstition, but his metaphysics is a pretty good approximation both of our naïve intuitions of physics and for the way the macroscopic world typically behaves in human environments. If you want to slide your cup across the table, you really do have to keep pushing it. Newton thus “reduces” to Aristotle (and Euclid, of course) once you provide a full accounting of friction (and some other footnotes). In the very same real sense in which the Earth is flat (spread your map on the table if you doubt me), it’s also Aristotelian. And, of course, at human scales, both Quantum and Relativistic Mechanics produce the exact same answers as Newton. All proposals of anything beyond modern theories similarly “reduce” to QM and Relativity at scales where the evidence is solid.
So we can be certain that Sean’s Big Equation is still going to be true millennia from now…but it may well seem as naïvely oversimplifed as Aristotle.
Cheers,
b&
Logicophilosophicus:
I’m starting to think that infinite profligacy is less of a problem than commonly supposed.
We tend to think of infinite sequences as being infinite non-repeating sequences, with the decimal expansion of π being the favorite example.
But there’re also infinite sequences with much more clearly-defined behavior. The decimal expansion of 1/17 is good for an example: 0.0588235294117647 repeating. Every digit appears at least once. Most but not all digits appear twice. There’s a double 8 and a double 1. If you rolled a ten-sided die sixteen times and got that sequence, you wouldn’t blink unless you were paying close enough attention to notice that it’s 1/17. And that sequence barely took more than half again as many numbers as the base (ten) to manifest. The very next odd number is an even better example. It would be trivial to write code to plot out bell curves from such infinite sequences…and a marginally better amateur mathematician than I could probably generalize that sort of thing.
And, again, this is just from the initial cursory look at small rational numbers.
So I would caution against your intuition leading you to conclude that infinite complex sequences are necessarily chaotically incomprehensible. You can easily come up with an infinitude of such examples, but you can just as easily come up with an infinitude of counterexamples. And we have overwhelming evidence that the Universe is not chaotically incomprehensible, so we should be reasonably confident that, if it is infinite, it’s infinite in a manner that much more resembles the infinitude of 1/17 than the infinitude of π.
Again, you’re making an aesthetic judgement.
Sean would argue that Many-Worlds is the simplest explanation, because it starts and stops with the Schrödinger Equation. All the other explanations have mechanisms for how only a single finite sampling of the infinite possible outcomes of the Schrödinger Equation could come to be realized. Everett dispenses with those mechanisms, and says that the Schrödinger Equation really is all you need for your explanation. And that you should no more be surprised that you only observe yourself in a small corner of the Equation than you’re surprised that you only observe yourself right now wherever you happen to be.
The dice roll mechanism is gone, along with all other mechanisms. There’s just the Equation, which happens to be infinite, but so are space and time, at least superficially.
As such, it really does deserve special consideration. If one of the competing interpretations can provide evidence of its equivalent of the dice roll, it would immediately become the overwhelming favorite. But Everett’s point is that we don’t need such evidence for the Equation to be complete…and that we shouldn’t go about manufacturing additional “stuff” to satisfy our Aristotelian intuitions until and unless evidence for such “stuff” can be produced.
Cheers,
b&
Logicophilosophicus:
Let go of your aesthetic objections for a moment. Imagine snatching a single branch of the infinite universal function out of the rest at a frozen moment in time. Consider how it would appear to those “inside” that snapshot…and you’ll see that it appears exactly as we really do observe reality.
And I think it’s very unhelpful to visualize it as a binary tree exploding in complexity…and instead as ripples on a pond. The waves are continuous. The double-slit experiment does not produce a single pair of branches, with one photon (electron, elephant, whatever) on the left and another on the right; rather, it produces a complete continuous continuum of rippling branches that we can visualize as the luminosity pattern when we run the experiment with the full power of the laser (electron gun, whatever).
The photon really is a wave, not a particle; its point-like appearance is an artifact of the interactions of observation.
And you are also a wave, with one of your ripples constructively interfering with the photon as its wave passes on the left, and another of your ripples with the photon on the right. Those ripples continue expanding outward and evolving independently. They’ll superficially be similar, indistinguishable even…but they’ve parted ways and will increasingly diverge even in superficial appearance with time.
Again, I’m not perfectly on board with M-W, myself. I still need to do some high-school-level optics experiments to rule out my own naïve objections, at the very least. But it really isn’t as outré as the common objections make it out to be.
Cheers,
b&
James:
No worries. To my own shame, I’ve struck out at others similarly in the past, so I can perfectly understand where that came from.
If it helps…feel free to go after my ideas hammer-and-tongs. Most people deserve respect, but damned few ideas do.
Cheers,
b&
JM
What have waves to do with time? I believe in observations., described as particles in locations. They come in series. The rest is inference.
Block time? The idea that a deterministic universe consists of block space-time is a denial of the fact of QM, irrespective of interpretation/model. Relativity cannot be a final explanation.
Ben G
“You can easily come up with an infinitude of such examples”
Show me. My complaint is Wittgenstein’s complaint – no one EVER. demonstrates an infinity, an infinitesimal or a continuum. They show you an algorithm, which can obviously be reiterated ad lib, and CLAIM to have produced some kind of infinity. In one of his lectures on the Foundations of Mathematics Wittgenstein asked Turing how many numbers he had learned to write down; Turing replied that if he had been anywhere else he would have said aleph-null (i.e. an infinite number of them). The point is that he knew Wittgenstein wouldn’t wear it – he’d requiire evidence, and an infinite amount of evidence is not possible.
Wittgenstein’s objection was not aesthetic, and nor is mine.
Your MWI “continuum” is not what we see: we observe individual states (christened “eigenstates” to imply that they are points in a continuum, but that continuum is NEVER observed., any more than the bell curve – the limit to which the values in Pascal’s triangle (the binomial coefficients) tend.
Whether MWI is “true” is meaningless in one sense: Everett himself acknowledged that other interpretations give EXACTLY the same predictions within any possible limits of experimental accuracy, and can never be distinguished by experiment. MWI merely satisfied a “physicalist prejudice” – sounds like an aesthetic judgment at best…
…and BTW the standard objection to MWI is that Everett introduces but never defines or justifies or supplies a mechanism for measurement. So there are indeed mechanisms in there.
Logicophilosophicus:
A better demonstration of the differences between science and philosophy — including the utility of the former and obstructionist uselessness of the latter — could not be made.
For your exact same objections can be applied to anything. I would tell you that I have overwhelming, unshakable confidence that the Sun rose in the East this morning, that it has done so for billions of years, and will continue to do so for billions of years. But can I show you right now this morning’s or tomorrow’s sunrise? Clearly not. I can show you evidence overwhelmingly supportive of my claims, but the Sun isn’t actually rising right now where I sit, so I can’t show you the Sun rising — and I clearly can’t show you the Sun rising at times other than right now.
Philosophers far too often get simply paralyzed by such pedantry, whereas a reasonable person will simply adjust error bars accordingly.
Do I know for certain that the Sun really does rise in the East? As practically makes no difference, yes, but I will certainly concede to a footnote that some insane conspiracy theory could actually hold such that I am mistraken in my conclusion.
And it is with similar certainty that I will tell you that the sequence 1/2, 1/4, 1/8… has an infinite number of elements, an infinite number of which are infinitesimal, and the whole lot sum to exactly one.
I don’t need to actually observe every single element of the list in order to conclude that there are an infinite number of them, infinitesimals and all, any more than I need to watch the Sun rise a trillion times to conclude that, with the aforementioned temporal limits, it always rises in the East.
Yes and no.
“Yes,” but only in the trivial sense that we also do not observe all time simultaneously but instead only the perpetual now. When you understand why you don’t object to the existence of more than the present moment despite the fact you’ve only ever actually observed the present moment, you should understand why your objection to not simultaneously observing all branches of the waveform is similarly invalid.
And, “no,” because what we observe is exactly what we’d expect to observe if M-W is correct. We can’t necessarily distinguish (at present) between the different interpretations, but it is emphatically the case that the observations we make are exactly the ones predicted by M-W.
The “measurement” is the entanglement of the states of the phenomenon being observed and the stuff doing the observation. In the double-slit, the wave in the photon field corresponding with the single photon that gets diffracted constructively interferes (if you’ll permit some poetry) with all the waves in the electron field corresponding with all the atoms in your CCD array. Each of those interferences results in entanglements that correspond with the different branches.
The “mechanism” at work is the same standard Feynman diagram as all physicists know and love.
Cheers,
b&
Ben,
“pressed for time, so I’m just cherry-picking the low-hanging fruit.”
It’s interesting you should put it that way. Am I making points you find difficult to rebut, or just understand? I’d be more than willing to clarify any specific issues.
” Typically, all the interesting and complex stuff happens in the mixing, when you get the whorls and vortices and fractal stuff…”
Yet isn’t that what we really observe and complexity versus simplicity are concepts we just assign as conceptual parameters? My point being these are effects generated in a convection cycle, where heat is constantly radiating out, while cooler structures coalesce inward and that not only applies to the terrestrial environment on which we evolved, but all the way up to the galactic relationship of radiation expanding outward, while mass/structure gravitates/coalesces inward. While this might seem an overly simplistic generalization, it might be worth pursuing for further insights. Especially if you consider the processes infuse our biological, sociological and economic realities. Just think in terms of circulation systems, from blood to money. All those whorls, vortices and fractal patterns apply to much of what goes on.
““equilibrium” is a very precarious concept, with Heisenberg demonstrating that, at small scales, all is (at least random-seeming) chaos seething with uncertainty.”
Yes, but don’t positive/negative fluctuations imply equilibrium? -1+1=0.
” Edwin Hubble famously observed inflation, and the constant (~70 km/s per megaparsec) still bears his name. ”
Hubble observed redshift. Inflation was proposed in the 70’s by Guth, Linde and Steinhart, to explain why the background radiation is as smooth as it is, since the opposite parts of the universe are moving away from each other too fast for the information to travel.
To retroactively apply that term to the expansion based on redshift is an example of word inflation.
“And this technique shows two striking facts: there really is exactly as much mass as is necessary to account for the motions of the galaxies, and the mass is only roughly aligned with the bright stars. So we now know, without a doubt, that there really is a bunch of actual, real, honest-to-goodness “stuff” that’s found in and around galaxies that accounts for the missing matter…”
The lensing matches the rotation. I would still ask whether gravity is an effect of mass, or mass an effect of gravity.
“it really doesn’t describe biological evolution after all.’
As I recall, it was more based on the geological record. That long periods of stability are punctuated by drastic events and then new organisms rise to fill the gaps and stabilize again. I would add that evolution strives for ever greater efficiency, which compels ever more specialization and thus decreased adaptability. Setting the stage for cascading disruptions, when those large events occur.
“Second is the way everything “reduces down” to the old stuff.”
I have problem with reductionism. To use an analogy, if we reduce a body down to its most stable structure, we would have the skeleton, but often it seems science and math assume this to be the seed from which the body sprang in the first place. For instance, Euclidian geometry is assumed to be foundational to nature, rather than just very simple concepts to easily grasp. Yet there are few naturally occurring straight lines and right angles. Then we get to ideas like dimensionless points, as an ideal of location, which are mathematically self negating, as they are multiples of zero. So then it is argued a line is made of of infinite dimensionless points, which is logical poppycock. Even infinity multiplied by zero is still zero. if you simply have lots of dimensionless points, not at the same location, they could as easily be volume or area. You have to specify the line, which is the basis of the line, not the points.
So you can’t reduce a line to points and still have a line.
Three dimensions are really just the xyz coordinate system and are a mapping device. They are no more foundational to space than longitude, latitude and altitude are foundational tot he surface of this planet.
The problem seems to be sociological and generational. What is speculation to one generation, is accepted by the next and religion to those following. Until it isn’t. Ie. the punctuation.
Logico,
That was an analogy, or example of how definitions might be foundational to understanding, though only expressions of what they define.
I think we might be in agreement that “spacetime” is not an adequate physical explanation for the math of Relativity.
Ben G
I wrote (concerning Turing being put on the spot with regard to the reality/realizability of infinities): “The point is that he knew Wittgenstein wouldn’t wear it – he’d require evidence, and an infinite amount of evidence is not possible.”
You wrote: “A better demonstration of the differences between science and philosophy — including the utility of the former and obstructionist uselessness of the latter — could not be made. For your exact same objections can be applied to anything… [e.g. confidence in] the Sun rising — and I clearly can’t show you the Sun rising at times other than right now. Philosophers far too often get simply paralyzed by such pedantry, whereas a reasonable person will simply adjust error bars accordingly.”
You have that totally assbackwards. Wittgenstein was a breath of fresh air, exactly the opposite of the pedantic nitpickers – the antidote, in fact. However, you miss the point yet again. Wittgenstein did not demand that Turing there and then should write down an infinite list of numbers: he simply pointed out that it is IMPOSSIBLE EVEN IN PRINCIPLE to do so. It is perfectly possible IN PRINCIPLE to show me a sunrise, or to show me evidence of a billion sunrises. It is possible in principle to assign the integers in sequence one at a time to each possible combination of all the individual particles in the universe; that might take us to something like the factorial of the hundredth power of ten; but we would not have scratched the surface of aleph-null (“infinity”).
You claim that mathematicians perform calculations involving actual infinities. Turing would disagree. They manipulate equations, then turn the calculation over to a computer, which works strictly with finite numbers. The manipulation depends on axiomatic rules which have been chosen to avoid results that contradict observables. (Mathematicians play a more dangerous game because the stakes are lower.)
“And it is with similar certainty that I will tell you that the sequence 1/2, 1/4, 1/8… has an infinite number of elements, an infinite number of which are infinitesimal, and the whole lot sum to exactly one.” I asserted there is no proof of this – you have not attempted nor cited a proof. You know what I’m going to say: Show me. Like Wittgenstein, I don’t require the infinite calculation to be completed in practice, only in principle.
“I don’t need to actually observe every single element of the list in order to conclude that there are an infinite number of them…” Indeed. All you need to do is supply a mathematical proof that doesn’t smuggle in the actual existence of infinity among the axioms. All these examples of infinity are examples of unfinishable lists, and that should stand as the definition of infinity.
Yes and no.
“When you understand why you don’t object to the existence of more than the present moment despite the fact you’ve only ever actually observed the present moment, you should understand why your objection to not simultaneously observing all branches of the waveform [Schrodinger wave function] is similarly invalid.”
What? I have observed all the “eigenstates” in my personal history; the number of eigenstates not realized in my universe which I have observed can be counted on the fingers of one foot. By “similarly” you seem to mean “having no resemblance/relevance whatsoever”.
“We can’t necessarily distinguish (at present) [Everett reckoned not ever] between the different interpretations, but it is emphatically the case that the observations we make are exactly the ones predicted by M-W.”
The mathematics makes a prediction (for THIS uiniverse), not the interpretation. And, in any case, you should have written: “It is emphatically the case that the observations we make necessarily constitute an infinitesimally small subset of the predictions of MWI” – and since, in your view, infinitesimal = zero, that is zero evidence for MWI.
I wrote: “the standard objection to MWI is that Everett introduces but never defines or justifies or supplies a mechanism for measurement.”
You replied: “The ‘measurement’ is the entanglement of the states of the phenomenon being observed and the stuff doing the observation… The ‘mechanism’ at work is the same standard Feynman diagram as all physicists know and love.” (Entanglement is definitely a word to avoid in this context.)
As you well know, Feynman diagrams are not mechanisms at all, just pictorial fictions which usefully correspond to calculating short cuts. All they show in the case of electrons and photons is that a photons go from place to place, electrons go from place to place, and each electron emits or absorbs a photon at some moment (you could say ‘at every available moment’). Each possible trajectory or interaction has an amplitude, loosely a probability, which is not indicated on the diagram. And here’s the thing, the resultant trajectories/interactions for an electron cannot work given an infinite number of possibilities, so Feynman (and Schwinger and Tomonaga – 1965 Nobel Prize) cooked up a ‘shell game… a dippy process… hocus-pocus” to prevent infinite answers to calculations, which involves notionally truncating the steps short of infinity. It is called, as you know, renormalization, and it has no place in Everett’s MWI. (I believe Bell discusses this mismatch as a problem for MWI.)
You can see that in the truncation of infinite calculations there is a parallel between computing and renormalization, and that is why I believe the necessity for renormalization is both evidence for a computational universe and evidence against actual infinities. Feynman presumably felt the same – for most of his professional career he sought a discrete chequer-board model of reality (analogous to a cellular automaton).
I await your proofs that:
a) 1/2 + 1/4 + 1/8… + 2^(-n)… = 1 (tends to, or approaches the limit, will not do)
b) MWI predicts the need for renormalization
“The electron just gets along fine without it”.
Does it, really? An electron is an object that apparently “smells” (Feynman’s terminology) out all possible paths while embarking on its motion to a certain destination. This is the essence of the path-integral formulation of quantum mechanics. Question is how does it do it? How on earth does it add up all the amplitudes corresponding to all the different possible paths and manifest itself at points with probabilities commensurate with the resultant sum?
However, I am not saying that this supports the theory of backward causation in any way. An electron in a neuron behaves in the same manner as that in the inanimate objects, at least as far as we’ve been able to observe. All I want to point out is that looking at the behavior of the electron, it’s difficult not to come away with the feeling that the goddamn thing is intelligent.
What’s perplexing though is that an intelligent object usually can exercise a choice of behaving one way or the other under a certain circumstance, in other words there is a certain amount of unpredictability associated with it. But for the electron, that’s not the case. The electron, in any given circumstance, behaves absolutely predictably, the probabilities for all outcomes are sacrosanct, the electron never violates them.
This then means that maybe the electron is both intelligent and unintelligent at the same time, a curious duality that perhaps afflicts all conscious objects that are there. Maybe all objects are linear superpositions of the qualities of intelligence and unintelligence and the degree of intelligence is dialed up as one progresses from the electron toward atoms and molecules, followed by viruses and cells and tissues, and finally living beings, culminating in man, in whom the dial is almost fully turned toward intelligence.
Of course this doesn’t explain why a brick is fully unintelligent, in other words, what is not known is the quality that dials up the intelligence of a particular collection of atoms and molecules as opposed to another.
So could quantum mechanics have a role to play in the phenomenon of consciousness?
SB
“…for aught we know, or for aught that the new science can say to the contrary, the gods which play the part of fate to the atoms of our brains may be our own minds. Through these atoms our minds may perchance affect the motions of our bodies and so the state of the world around us. To-day science can no longer shut the door on this possibility; she has no longer any unanswerable arguments to bring against our innate conviction of free-will.” James Jeans
Logico,
By minds, what does he mean actually? That which play the part of fate to the atoms of our brains? But how is the mind itself independent of the dynamics of the atoms of our brains? Isn’t the mind also a product of that dynamics? How can something, that emerges out of that dynamics, control the dynamics itself?
Regarding free will, consider this thought experiment. Suppose there is an observer who can perceive of time as being what it really is, namely a fourth component of “space”, in other words someone who is not shackled to the perception of time as being something that flows from one instant to another. To him the entire spacetime history of the universe is laid out in the same sense that space is laid out for us. So from this vantage point, everything from the beginning of time to its end is eternal, it has been existing forever.
Whither then, free will?
SB,
Here is another thought experiment; Say you have a spinning ball with a pin stuck in it and a flashlight shining on it, as a model of a person on Earth.
As it spins, the pin alternates between being in the light and in the dark. So these events come into being and are replaced. Does this make sense?
Now as cognizant creatures, we experience reality as flashes of perception, so we naturally think of time as the present moving from past to future events. Yet if you consider the above experiment, it is the events which come into being and fade, so it is they which go future to past. Tomorrow becomes yesterday because the earth turns. Like temperature, color, etc, time is emergent.
So there is no need of the entire history of the universe to exist on some fourth dimension. Time emerges from activity. It is just that we see it from a very subjective point of view. Just as we still see the sun as rising in the east and setting in the west and constructed elaborate mechanical theories to explain it, when it is the earth turing west to east.
So it is the occurrence of events, as all input comes together, which determines their outcome. They are first in the present, then in the past. Our mental decision making processes evolved as another input into this process.
SB
1) Of course Jeans’s speculation assumes that the mind is not emergent. He is assuming that the brain is a tool of the mind. Once Heisenberg had declared that causality (determinism) does not exist at the quantum level many scientists and philosophers pointed out that this left room for subtle influences to nudge physical events. This conclusion does not depend on a specific theory of mind. Suppose a strict causality is analogous to alphabetical order, abcdef… Violation of causality should on some scale stick out like a sore thumb: abcdefXYZghi… Quantum effects were apparently random, analogous to aqwtgbm… How would we ever detect a nudge, aqwGTbm… ?
2) The absence of causality, and the irreversibility of quantum processes, ensure time’s status. The space-time block universe is based in part on reversibility. How do we reconstruct the wave function from an eigenvalue? Analogously, 2+2=? The answer is unique. ?=4 There is no limit to the possible answers; if there was a right answer, then (barring memory) it can never be found.
John Merryman,
“So there is no need of the entire history of the universe to exist on some fourth dimension. Time emerges from activity.”
So now you come around. I have said this from the first page of this comment thread.
What we think of as time (that passes like a river) is an illusion, “activity” is just a comparison of two very similar states. This is what we interpret as time that flows.
I’m late to the party and haven’t read all the comments, but I see a lot of references to free will. What has free will to do with downward causation?
Even if downward causation existed, your actions would surely be a product of who your are at that point. And who you are seems to me to be fully explained by your genes and environment (past and present). Downward causation would only create a detour in the causal chain.
If you want to argue for a compatibilist version of free will that is of course perfectly fine.
Moe,
You do appreciate that without a time dimension as an integral, physical part of the “fabric of spacetime,” it leaves space as a vacuum, whose only two features are being what light travels through at C and is infinite, as there is no change to it.
That upsets a few shibboleths.
“If you want to argue for a compatibilist version of free will that is of course perfectly fine.”
And also seems pointless, and like a way to rationalize feeling good about ourselves.
It seems to me no different that trying to create some compatibilist version of “god” so that we can call something god.
The MWI *seems* to be OK, but it leaves a sense of something still being ‘not quite right’. Perhaps it’s just our human intuitions misleading us. I’m in the same camp as Ben here…I think MWI is probably right, but I just have nagging lingering doubts. It’s the ‘block universe’ picture that continues to worry me a bit.
There’s a *really* close link between consciousness and ‘the arrow of time’; that’s why I put forward my radical suggestion that consciousness and time are the same thing ( a form of panpsychism, where qualia are identified with some properties of causal relations that are present in nearly everything to some degree).
In the case of MWI, again, to go from that sort of advanced ‘block universe’ picture to what we actually perceive, you’d really need to understand how the mind is constructing our sense of time perception from what is a really abstract physics picture. So , again, it really does seem like cognitive science is getting involved in physics here!
A striking example of how time perception is associated with consciousness is music. Notice when you listen to music, how the beats and rhythms are ‘entraining’ your conscious perceptions and provoking emotions. A ‘rhythm’ is a repeated time sequence. You really have to suspect that consciousness is closely linked to some sort of ‘time ordering’ or ‘time sequencing’ system in the brain. Anyone have any thoughts on this?
Zarz,
Frequency and amplitude. Does it occur to anyone that while the rationality is sequential(frequency), like words, emotion is when amplitude spikes. Like the beats in music.
Does it occur to anyone that MWI argues the past remains probable. Just as determinism argues the future is pre-determined. Can’t anyone come up with a theory to explain why the future is probable and the past is determined? Just as an exercise. Or would that be too intuitive?
I have an idea! There is only this present state and it is constantly fluctuating and generally whirling around. There is no external frame to know where all particles are and and where they are going. Uncertainty Principle, remember that one? So while future events can be predicted, depending on the amount of available information, there is no frame from which all input can be known for all events. Unless you are God, of course.
Meanwhile the past happened. No going back and changing it, cause time is asymmetric!
Crazy, I know.
zarzuelazen,
Sure there are close links between consciousness and time. I can think of two: we can only remember the past, and our actions only ever affect the future. (In ordinary life at least: delayed choice quantum erasers are not part of ordinary life.) But both these facts can be explained via entropy.
The “block universe” (now there’s a dubious metaphor) is almost impossible to think about with tensed verbs, so I can see how we English speakers find it worrying. Solution: learn Chinese?
@Paul,
The distinction you make between us ‘remembering the past’ and ‘affecting the future’ isn’t valid in the ‘block universe’ picture of physics. Physics makes absolutely no distinction between past and future, nor is the notion of ‘causality’ anywhere in physics., as Sean has rightly pointed out numerous times.
So either you have to dispute the physics, or you must agree that the statement:
‘We can affect the past’ is just as correct as the statement ‘We can affect the future’.
Paul,
“delayed choice quantum erasers are not part of ordinary life”
But this is just an observable case of how the MWI actually works in all cases.
I don’t think it makes sense in the Copenhagen interpretation, as there should be no uncollapsing of the wave function after it has happened, right?
There is a discussion here with at least a few philosophers that go over the incoherences or problems with Sean Carroll’s views:
http://www.consciousentities.com/2016/09/downward-causation/