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, FQXI is a Templeton propaganda machine. If you can fit a grain of salt in your mouth, it’s too small to take with anything Templeton pays for. They are true masters at the art of corrupting science with Christian theology. No matter what, they always manage to put an implied “ergo, Jesus” somewhere, no matter how subtly, no matter how non-Christian the bought-and-paid-for researcher. Even Templeton-funded studies showing no or negative correlations between prayer and rates of healing get spun in a way supportive of faith.
That aside, you seem to have completely missed the point I was trying to make.
The Big Bang was ~13 billion years ago. The observable universe is ~100 billion light years across. If we take your objections about rulers and the like seriously, we’d have to conclude that the universe is at least ten times bigger than it could possibly be.
The fact that cosmologists are the ones telling you those dimensions and the speed of light and that they’re not at all disturbed about the apparent dichotomy should tell you that it’s entirely your own misunderstanding to blame.
If you’re willing to admit that you’re worng, cosmologists are right, and are open to having your confusion resolved, we can help you. But if all you want to do is parrot back the counterintuitiveness of non-Aristotelian physics and insist that anything that doesn’t make sense in the context of your living room is impossible, there’s no point to further discussion.
b&
Ben,
I suppose John Templeton’s beliefs must corrupt anyone associated with it;
http://fqxi.org/community/forum/topic/2682
This is a very simple question that me, a rube, is asking and has nothing to do with any specific age or size;
If the vacuum through which light travels is not space, than what is it and why is it being used as the denominator in this relationship? If the distance between galaxies was being used as the denominator, then the issue would be; why does it take light longer to cross and it would be a “tired light” issue.
Presumably the denominator is the standard.
John Merryman:
See, it’s that kind of language which we can’t get past. Knowingly or not, you’re asking a leading question. I can’t answer a question you pose with language like that any more than you can answer me when you stopped beating your wife.
Michelson and Morley very famously demonstrated that there is no Luminiferous Aether (equivalent to “the vacuum” as you’re using the term) within which light propagates. It’s very counterintuitive to think of light being electromagnetic waves without a medium to propagate them, but we’ve known for over a century, now, that that’s the case. And, until you can let go of your Aristotelian intuitions about how you think physics should be and accept what experiments show it to actually be, there’s no hope of making any progress.
Cheers,
b&
It all looks very tangled up and circular. I think it all resolves, conceptually if not rigorously, if one sees all our realities as fragmented projections from another far higher realm. Fragmented into realms of abstraction with names like consciousness or physics. They don’t meet in the middle for us because we can’t see the bigger fabric they both emerge from. Final causation derives from a focus point not in our perceived realm at all.
Our consciousness is clearly driven to uncover causation. But if final causation stems from outside of our realm and perception, then causation within our realm is no longer required to have absolute finality.
As we experience it, causation only really works as a concept within certain levels of ’emergent’ phenomena, such as say, psychology, maybe crossing boundaries occasionally, from say emotion to biochemistry.
By my thesis, our physics becomes a projection from deeper physics. Still physics, in the basic sense, but we can’t get to it because we aren’t smart enough and are unable to perceive the relevant maths, parameters, interactions and dimensions. We have no inkling of them.
Likewise, our ‘parameters’ of consciousness, our concepts, emotions, logic, etc, are things which derive from another realm. They are not emergent within the natural realm, they are projections from another realm. The connective orchestration between our layers of abstraction are invisible to us. The things we find reality in are emergent in a different sense to the usual use of the word here. They emerge from behind a veil. the higher being behind the veil engineered the veil and has made sure they are hidden.
Constant means light always travels the same number of length units along the “rubber band” per time unit. The stretching of the rubber band means adding length units, not stretching length units.
Causation itself of course belongs to a ‘high level emergent’ category of abstraction; consciousness. In a reductionist framework, causation needs the higher layers to have any existence at all as a concept. Core equations plus boundary conditions are just information. It takes conscious thought to define them as causation, assuming one thinks they are.
Neil:
Indeed, this is just another way of rephrasing the description of dark energy, or Einstein’s cosmological constant. Inflation means that more space is being created (ignoring the unintentional anthropological / theological implications one might be tempted to read into that phrasing) constantly, being “inserted” everywhere and “pushing apart” that which had formerly been close. But the energy of any given volume of space is always constant. As more space is created, the energy grows in concert with the additional space; that’s the accelerating inflation of dark energy.
Don’t ask me how to reconcile this with Lawrence Krauss’s math that sums the energy of the Universe to zero. I still haven’t warped my brain ’round that one. But, until I do, I’m okay with taking it on face value, because all other physicists and cosmologists at least approximately agree with him, best I know.
Cheers,
b&
Neil, Ben,
“The stretching of the rubber band means adding length units, not stretching length units.”
Exactly. What is the basis of these units? It’s not covered by the theory, just assumed. If there is some underlaying dimensionality, within which this universe is contained and it determines something so fundamental as the speed of light, then wouldn’t it be the real dimension of space? As you say, it is the “unit,” the denominator. In which case, this would be an expansion in that larger “space” and the problem that we appear at the exact center of this expansion, with all those distant galaxies redshifted proportional to distance, would need to be addressed. Are we at the center of the universe?
John Merryman:
That’s your inner Aristotle speaking, telling you that there has to be a Luminiferous Aether to serve as the medium underlying all this. Again, Michelson and Morley demonstrated that the medium actually isn’t there, in direct contradiction of all intuition. And it’s their demonstration that provided the kick in the pants that eventually resulted in Relativity, the fundamentally counterintuitive nature of which you’re struggling with.
You’re still insisting that we point you to the location on the map where the Sun sleeps at night. Trust us that you have to let go of even your most basic conceptions of geometry before you’ll be able to comprehend how impossible it is for us to show you the map with the Sun’s bedtime cave location marked on it.
Cheers,
b&
Ben Goren
Thanks for pointing out that there is nothing significant left to understand, I can go do the gardening now and forget about hard problems. Phew
Ben,
A medium is a medium. Like water, or air. Or society. A vacuum is when there is no medium, like when the air has been sucked out of a bell jar. I guess this really is a waste of time.
Per chance do you actually know why Einstein proposed the Cosmological Constant? To balance gravity, which he viewed as a contraction of space, thus concerned it would collapse the universe.
Now where is gravity most predominant? In galaxies. So logically where would one look for the CC? Between galaxies. As you point out, there appear to be more units of space appearing between galaxies. Yet you overlook that for space to contract into galaxies, units of space would be erased there. These two effects counterbalance. Omega=1. That is why the universe adds up to zero.
John Merryman:
Yes.
And the fundamental fact of physics that I can’t seem to get across to you, experimentally verified and universally accepted for at least a century by now is that:
LIGHT DOES NOT PROPAGATE WITHIN A MEDIUM.
Any and all attempts to put light within the context of a medium are going to give you incorrect answers and lead you into confusion.
Yes, I know — it’s counterintuitive and bizarre to think of waves without a medium in which the waves are waving…but nature doesn’t care about your intuition. Nature simply is, whether you like what it is or not, whether or not you think that’s how it should be or not.
When you’re ready to stop trying to cram light into a non-existent medium, we might be able to make progress. But, until then, perhaps you really are better off tending to your garden.
b&
Ben,
Where do you get “medium” when I say vacuum?
Any sort of medium would slow and dissipate the light as heat.
John:
The properties you are attributing to the vacuum are those of a medium. Light does not propagate within the vacuum, for example. Your comments about underlying dimensionality, stretched units, denominators…all those only make sense if light is propagating through a medium of some sort.
Which it, once again, most emphatically, really, truly, honestly, is not.
You’re still looking for the cave in which the Sun sleeps at night, with that through which light propagates / is measured by / whatever being the cave.
Cheers,
b&
John
To paraphrase Einstein, space is what you measure with a ruler. But the ruler does not have to be made of wood, or any medium. For instance, the meter is officially measured as the distance light travels, in a vacuum, in 1/299,792,458 seconds with time measured by a cesium-133 atomic clock.
Neil,
Yes and if those galaxies are moving away, such that it takes light longer to cross the intervening distance, that ruler isn’t stretching. It takes more such units, not stretched units. So whatever the ruler of light speed measures, it is not expanding, only the distance being measured by in these units.
Ben:
“Computation is a physical process. There are no known examples of non-physical computation, and there is no plausible physics that supports non-physical computation.”
Well, as I mentioned earlier, there do seem to be quite a few smart scientists proposing that computation/information is more fundamental than physical reality (see my earlier list of supporters). Stephen Wolfram is another big name that supports the idea. If we subscribe to Sean’s emergence picture, it’s quite possible that there’s another layer beneath the physical level, and it’s computation. I was skeptical, but after more thought, I’ve gradually started to come around to the idea.
Also, pan-computationism: It’s admittedly more plausible than pan-psychism, although both ideas don’t necessarily contradict each other. Is there anything in physical reality that isn’t computable? If not, then it seems that pan-computationism is true.
John wrote:
Yes and if those galaxies are moving away, such that it takes light longer to cross the intervening distance, that ruler isn’t stretching. It takes more such units, not stretched units. So whatever the ruler of light speed measures, it is not expanding, only the distance being measured by in these units.
I believe that statement is correct. If not, Ben will correct before long.
Neil,
Thank you. I’m just trying to make a point that seems obvious to me. Yes, it does contradict current theory and I’m not going to psychoanalyze why no one else seems to see it. Like a lot of things, I could well be wrong, but I would want an explanation for what seems a fairly basic observation, not lots of side issues and insults.
1) There seems to be “wiggle room” in a place Sean *didn’t* address. It is the qualifier “even if not exclusively” which appears in step #2. If anyone believes they can flesh out a complete argument from the bones of #1-4, *without* dropping that qualifier, I’d love to see what you’ve come up with.
2) Assuming for the moment that a complete argument *can* be fleshed out from #1-4, why does Sean believe that if downward causation *did* exist, *that* might provide “wiggle room”? How, specifically, could its existence invalidate such an argument?
Ben:
“Sean’s Big Equation is already something fully Turing-computable, if that’s the point you’re trying to make…but I believe you’re confusing things mightily to conclude that something which is computable is therefore a computation.”
It seems to me that the question of whether you can point to anything in physical reality that’s non-computable is a critical point here!
If absolutely *everything* in physical reality that you can point to turns out to be computable, then this is actually evidence that computation is *more* fundamental than physical reality!
Remember, when you argued against panpsychism by pointing to something in physical reality that *doesn’t* seem to have cognition going on (i.e chairs). That was an argument in favour of the point that physical reality is more fundamental than cognition.
So if physical reality is more fundamental than computation, then you should also be able to point to something in physical reality that isn’t computable. If you can find absolutely nothing in physical reality that is non-computable, this is an alarming result for materialism – alarms should be ringing here! Because it is indeed evidence that computation is more fundamental than physics.
John
Well, if understood it correctly, your comment at 4:48p does not seem to contradict current theory.
John Merryman,
You are actually correct. The measurement of space is an arbitrary unit. This is why we have distance measured in lightyears.
It is very important to understand that this is the most common unit for distance on a large scale. So, first we decide how far away something is, based on the speed of light itself, which we hold constant as a ‘fact’. This can be done with red-shift if triangulation won’t work.
As I pointed out earlier, this is where relativity should be acknowledged, but rarely is talked about.
If instead of holding the speed of light as a constant, we instead assume that the amount of space in the universe is constant, then you have to solve the equations to say that time itself is what has been changing.
In this case, the speed of light was relatively much much faster when the universe was ‘young’. As the time of the big bang, light would have been able to travel across the entire universe (which would have a fixed size) almost instantly. As the rate of the passage of time changed, the speed of light slowed, eventually to it’s current speed.
With this view, when we look at early light, it has a longer wavelength because it covered the same (fixed) distance in less time, with the same number of oscillations per unit time, but the unit of time was changing during the travel, relative to the current unit of time.
No matter what anyone tells you, this can all be worked out as being the same thing as space expanding since the big bang, while time stays flowing at the same rate. It is impossible to tell the difference, so there is no difference. It is all in your point of view.
The main point is that most of the equations and theories have been worked out from the reference frame of the speed of light is the thing held constant.
To say that actually really is physically constant is a circular discussion. It depends on measuring space and time, both of which are most easily measured using light.
This is all about bringing all discussions to a common frame of reference, so that we can communicate ideas to ither people. It is about finding a common language. It is not about what is “true and real”.
Neil,
It does go back to why they argued for space itself expanding, rather than an expansion in this overall space, because we appear as the center. By arguing that space is actually expanding, it could be argued that every point appears as the center.
So if there is this overall space, as being measured by the speed of light, then wouldn’t the issue of why we appear at the center, with all those distant galaxies redshifted directly proportional to distance, become a problem again?
Here is an interesting idea;
http://fqxi.org/data/forum-attachments/2008CChristov_WaveMotion_45_154_EvolutionWavePackets.pdf
The premise of which is that redshift as only being possible due to recession is based on single spectrum photons, but when the light of entire galaxies is distilled to just a few photons, they are multi spectrum, which would redshift proportional to distance. Making it an optical effect and explaining why we appear as the center.
Moe,
It is still comparing two metrics, so one is the denominator and one is the numerator. If we say the distance between galaxies is the denominator, then the question is as to why the light slows and it is a tired light issue. By saying it is “space expanding,” then C is being used as the denominator and the galaxies are receding from each other, in terms of the speed of light, but that makes C the standard. Which is not what is expanding, only more units are added. Yes, it is all relative, but the specific issue is that it is being argued that “space expands,” when they go and use another metric as a standard to compare the supposed expansion and if it is the standard, then it is space. The “ruler,” as Neil points out Einstein said.
Ben G
You write that the concept of a fundamental reality is incoherent: not so – the/your alternative (equivalent to turtles-all-the-way-down) is incoherent. Infinite regression is recognised as an absurd consequence, e.g. to justify Richard Dawkins’s argument that if a big/complex universe requires a bigger and more complex creator to account for it, then what accounts for the creator? (Gods-all-the-way-down?)
Einstein, Heisenberg, Schrodinger, Wheeler, Weinberg, Feynman… all believed that there would be a fundamental level of reality, and it would be simple. Physics (including cosmology) currently has scores of particles and their antiparticles, a dozen or more independent constants, incompatible accounts of gravity and quantum forces, mysrterious ad hoc fudge factors (dark matter, dark energy, the inflation field)… Most of these were not known when Einstein objected to a universe made of “bits and pieces”. And there is no credible explanation within this physics for a consciousness that understands any of it, or cares about any of it.
Most quantum physicists – and certainly all who accept the possibility of Everett’s interpretation – believe that a key element of fundamental reality is the universal wave function, which is said to evolve deterministically in a Hilbert space of some vast number of dimensions: the wave function cannot exist in space-time. Hilbert spaces – vector spaces – are mathematical, not physical. We need a way to make sense of physics plus mathematics plus consciousness. Axiomatically claiming that physics achieves this – creating the Hilbert space? thinking about it? etc – doesn’t cut the mustard.