Saturday, May 30, 2015

String theory advances philosophy. No, really.

I have a soft side, and I don’t mean my Snoopy pants, though there is that. I mean I have a liking for philosophy because there are so many questions that physics can’t answer. I never get far with my philosophical ambitions though because the only reason I can see for leaving a question to philosophers is that the question itself is the problem. Take for example the question “What is real?” What does that really mean?

Most scientists are realists and believe that the world exists independent of them. On the very opposite end there is solipsism, the belief that one can only be sure that one’s own mind exists. And then there’s a large spectrum of isms in the middle. Philosophers have debated the nature of reality for thousands of years, and you might rightfully conclude that it just isn’t possible to make headway on the issue. But you’d be wrong! As I learned on a recent conference where I gave a talk about dualities in physics, string theory indeed helped philosophers to make progress in this ancient debate. However, I couldn’t make much sense of the interest in dualities that my talk got until I read Richard Dawid’s book which put things into perspective.

I’d call myself a pragmatic realist and an opportunistic solipsist, which is to say that I sometimes like to challenge people to prove me they’re not a figment of my imagination. So far nobody has succeeded. It’s not so much self-focus that makes me contemplate solipsism, but a deep mistrust in the reliability of human perception and memory, especially my own, because who knows if you exist at all. Solipsism never was very popular, which might be because it makes you personally responsible for all that is wrong with the world. It is also the possibly most unproductive mindset you can have if you want to get research done, but I find it quite useful to deal with the more bizarre comments that I get.

My biggest problem with the question what is real though isn’t that I evidently sometimes talk to myself, but that I don’t know what “real” even means, which is also why most discussions about the reality of time or the multiverse seem void of content to me. The only way I ever managed to make sense of reality is in a layer of equivalence classes, so let me introduce you to my personal reality.

Equivalence classes are what mathematicians use to collect things with similar properties. It’s basically a weaker form of equality, often denoted with a tilde ~. For example all natural numbers that divide evenly by seven are in the same equivalence class, so while 7 ≠ 21, it is 7 ~ 21. They’re not the same numbers, but they share a common property. The good thing about using equivalence classes is that once defined one can derive relations for them. They play an essential role in topology, but I digress, so back to reality.

Equivalence classes help because while I can’t make sense out of the question what is real, the question what is “as real as” makes sense. The number seven isn’t “as real as” my shoe, and the reason I’m saying this is because of the physical interaction I can have with my shoe but not with seven. That’s why, you won’t be surprised to hear, I want to argue here the best way to think about reality is to think about physics first.

As I laid out in an earlier post, in physics we talk about direct and indirect measurements, but the line that separates these is fuzzy. Roughly speaking, the more effort is necessary to infer the properties of the object measured, the more indirect the measurement. A particle that hits a detector is often said to be directly measured. A particle whose existence has to be inferred from decay products that hit the detector is said to be indirectly measured. But of course there are many other layers of inference in the measurement. To begin with there are assumptions about the interactions within the detector that eventually produce a number on a screen, then there are photons that travel to your retina, and finally the brain activity resulting from these photons.

The reason we don’t normally mention all these many assumptions is that we assign them an extremely high confidence level. Reality then, in my perspective, has confidence levels like our measurements do, from very direct to very indirect. The most direct measurement, the first layer of reality, is what originates in your own brain. The second layer is direct sensory input: It’s a photon, it’s the fabric touching your skin, the pressure fluctuations in the air perceived as sound. The next layer is the origin of these signals, say, the screen emitting the photon. Then the next layer is whatever processor gave rise to that photon, and so on. Depending on how solipsisitic you feel you can imagine these layers extending outside or inside.

The more layers there are, the harder it becomes to reconstruct the origin of a signal and the less real the origin appears. A person appears much more real if they are stepping on your feet, rather than sending an image of a shoe. Also, as optical illusions tell us, the signal reconstruction can be quite difficult which twists our perception of reality. And let us not even start with special relativistic image distortions that require quite some processing to get right.

Our assessment of how direct or indirect a measurement is, and of how real the object measured appears, is not fixed and may change over time with technological advances. It was historically for example much topic of debate whether atoms can be considered real if they cannot be seen by eye. But modern electron microscopes now can produce images of single atoms, a much more direct measurement than inferring the existence of atoms from chemical reactions. As the saying goes “seeing is believing.” Seeing photos from the surface of Mars likewise has moved Mars into another equivalence class of reality, one that is much closer to our sensory input. Doesn’t Mars seem so much more real now?

[Surface of Mars. Image Source: Wikipedia]

Quarks have posed a particular problem for the question of reality since they cannot be directly measured due to confinement. In fact many people in the early days of the quark model, Gell-Mann himself included, didn’t believe in quarks being real, but where thinking of them as calculational devices. I don’t really see the difference. We infer their properties through various layers of reasoning. Quarks are not in a reality class that is anywhere close to direct sensory input, but they have certainly become more real to us as our confidence in the theory necessary to extract information from the data has increased. These theories are now so well established that quarks are considered as real as other particles that are easier to measure, fapp - for all practical physicists.

It’s about at the advent of quantum field theory that the case of scientific realism starts getting complicated. Philosophers separate in two major camps, ontological realism and structural realism. The former believes that the objects of our theories are somehow real, the latter that it’s the structure of the theory instead. Effective field theories basically tell you that ontological realism makes only sense in layers, because you might have different objects depending on the scale of resolution. But even then, with seas of virtual particles, and different bases in the Hilbert space, and different pictures of time-evolution, the objects that should be at the core of ontological realism seem ill-defined. And that’s not even taking into account that the notion of a particle also depends on the observer.

For what I can extract from Dawid’s book it hasn’t been looking good for ontological realism for some while, but it’s an ongoing debate and it’s here where string theory became relevant.

Some dualities between different theories have been known for a long time. A duality can relate theories that have a different field content and different symmetries. That by itself is a death spell to anything ontological, for if you have two different fields by which you can describe the same physics, what is the rationale for calling one more real than the other? Dawid writes:
“dualities… are thoroughly incompatible with ontological scientific realism.”
String theory now not only has popularized the existence of dualities and forced philosophers to deal with that, it has also served to demonstrate that theories can be dual to each other that are structurally very different, such as a string theory in one space and a gauge-theory in a space of lower dimension. So one is now similarly at a loss to decide which structure is more real than the other.

To address this, Dawid suggests to instead think of “consistent structure realism” by which he seem to mean we need to take the full “consistent structure” (ie, string theory) and interpret this as being the fundamentally “real” thing.

For what I am concerned, both sides of a duality are equally real, or equally unreal, depending on how convincing you think the inference of either theory from existing data is. They’re both in the same equivalence class; in fact the duality itself provides the equivalence relation. So suppose you have convincing evidence for some string-theory-derived duality to be a good description of nature, does that mean the whole multiverse is equally real? No, because the rest of the multiverse only follows through an even longer chain of reasoning. You either must come up with a mechanism that produces the other universes (as in eternal inflation or the many worlds interpretation) and then find support for that, or the multiverse moves to the same class of reality as the number seven, somewhere behind Snoopy and the Yeti.

So the property of being real is not binary, but rather it is infinitely layered. It is also relative and changes over time for the effort that you must make to reconstruct a concept or an image isn’t the same I might have to make. Quarks become more real the better we understand quantum chromo dynamics in the same way that you are more real to yourself than you are to me.

I still don’t know if strings as the fundamental building blocks of elementary particles can ever reach a reality level comparable to quarks, or if there is any conceivable measurement at all, no matter how indirect. Though one could rightfully argue that in some people’s mind strings already exist beyond any doubt. And if you’re a brain in a jar, that’s all that matters, really.


agc said...

Nice use of equivalence classes - and nice demonstration of the way that those of us with a phys / maths training think.

nemo said...

I believe that "real" belongs, in some way, from our time perception. This is a consequence of the following considerations.

My idea is that due to Heisenberg principle, the time is not well defined (or, may be, the contrary). When I say "not well defined" it means that we can't say how it flows. If we don't know how it flows we can't give any definitions of the 'present time'. The "present time" concept is essential to fix events coincidence, hence the interaction.

Particles are oscillating forth and back in time, so the interaction between particle becomes impossible to define in term of classical mechanics. Through Heisenberg principle is clear that heaviest the mass and greater is the uncertainty. Bigger the energy (mass) uncertainty, smaller the time uncertainty.

Particles are neither a waves nor a particles, as time does not oscillate in the same way (amplitude of forth and back in time) for different massive objects. Interaction between particles are therefore dominated by probabilities as a consequence of time uncertainty. On the contrary, classical mechanic would work perfectly.

nemo said...

no interaction, no reality...

Giotis said...

Cosmos is a language, reality is a glossary.

Anyway that would explain Gell-Mann's interest on linguistics 😃

uair01 said...

This book is just tangentially related to your post, but it touches on reality and unreality. The claim is that both atoms and unicorns exist but just in different domains of existence. This reminds me of your equivalence classes. And it's in German:

peterfirefly said...

"Solipsism never was very popular, which might be because it makes you personally responsible for all that is wrong with the world. "

Why, if it's just your fallible senses -- or somebody/something else that is fooling the brain in your vat -- or the whole thing is just a simulation anyway?

JSV said...

I think you have all the ingredients in there.

I took this philosophical walk, rooted firmly in physics, and satisfied myself on the basis of a duality, but the notion of reality can have shades of grey.

Taking a reference fermion, whose position is known exactly, everything else is disjoint or is connected by degrees of separation. In determining what "reality" is, you can make progress by acknowledging other instances of entities that are in a similar state to your own.

[Crank self-promotion alert] So I built a 'physicality mechanism' based on phase solutions, basically an interference process for quanta and their fluctuations, as a way of deriving conventional (QFT) statistical fields. [preprint - DOI ref pending]

Its most direct form of reality is the point fermion state; with bosons connecting the fermion events in networks having varying degrees of separation, without violating causality.

There are fermions whose bosons 'miss' interacting, so can we say that they do not form a common reality? Perhaps not; they might eventually interact, by degrees of separation, so they will have influenced their evolution, and are a part of a common reality.

You would think that confinement presents a problem, but if these are deterministic networks, as described above, then the quarks are also interacting with other fermions (virtual or real, e.g. a with a discrete vacuum based on non-collapsed environmental bosons). That means that seemingly confined composite particles have a mass-energy component that is not totally confined. Granted, it's possible to theoretically construct a very tight non-interacting hadron using this mechanism, but it wouldn't last long in the presence of vacuum energy quanta (i.e. fluctuations), which would immediately decay it.

This confinement can also be applied to black holes and particle coherence, which is where it gets more interesting.

I've attempted to write an article on the subject of "What is reality?", but I never progressed beyond the draft, because it was full of philosophical traps that needed too many footnotes to clarify. I hope to revisit it after a round of core working.

Arun said...

Ontological scientific realism would suggest dualities, holography are mathematical only, and do not apply to our world.

Plato Hagel said...

I guess one could say then, that physical realism arises out of quantum realism, so there is that, and we might consider such use as depicted in deriving relativity out of something higher? How real is that? :)

JimV said...

There are not enough equivalence classes in your voting system to categorize this post. I wanted to give it eleven stars.

You already have all you need for a great book except a publisher.

Solipsism is useful to explain some of the bizarre comments you get - indeed. I am going to try to take that attitude myself so as not to get too upset by the strange and sometimes awful comments I see on the Internet. (It is harder to get upset when you can only blame yourself.)

Plato Hagel said...

The ALICE experiment benefited this year from the completion of a significant piece of its detector, its electromagnetic calorimeter, which has allowed ALICE scientists to make a much more detailed study of jets of particles that are suppressed as they attempt to move through the quark-gluon plasma. See: Experiments reveal new techniques in studying quark-gluon plasma

Yes, that is a 2012 article. Was it a gas or a fluid before that?

How did we ever get here? Pure states have to have some association to what is derived from quantum states? You see?

nemo said...

To bad my comment, I suppose

Holer said...

"I’d call myself a pragmatic realist and an opportunistic solipsist, which is to say that I sometimes like to challenge people to prove me they’re not a figment of my imagination. So far nobody has succeeded."

And nobody will ever succeed - solipsism is logically unassailable.

Haven't you already noticed that?

Arun said...

Is there any relationship between the classical canonical transformations of the Hamiltonian ( and modern QFT/string/gravity/gauge dualities?

Thanks in advance!

Sabine Hossenfelder said...


Yes, thank you, that was my point, you understood it correctly.

Anonymous said...

«Take for example the question “What is real?” What does that really mean?»

An unstated premise is that word meaning is objective and independent of your own mind.

Matt A said...

Hi - great article.

One question on layers of 'reality'. You say:

"Reality then, in my perspective, has confidence levels like our measurements do, from very direct to very indirect. The most direct measurement, the first layer of reality, is what originates in your own brain"

But then that:

"the multiverse moves to the same class of reality as the number seven, somewhere behind Snoopy and the Yeti."

implying that things existing only in the imagination are at the bottom of the pile. How do you reconcile these statements, or am I misunderstanding?

Are you taking an elimitavist materialist position on the mind, and saying that Snoopy and the Yeti have no existence beyond the configuration of matter in the brain that represent them? In that case they seem to have no reality at all, which makes it problematic to view the content of our mind as the "first layer of reality" doesn't it?

Alternatively (and I'm presuming you don't take this stance) the content of the mind has an existance beyond its correlated configuration of matter in the brain, in which case your "first layer" persists. But then I don't see the motivation for later implying it's less real than other elements of mind content that supposedly match (or at least pragmatically represents as I'd put it) the outside world.


Arun said...

The first I heard of solipsism was long, long ago in a page-long story in a science-fiction volume, where a certain Jesus H. Christ, a solipsist, was in a hospital room (I think) and pursues his solipsism to the extreme, willing away the sounds, the smells and the sights until there is nothing left but him. Then, feeling lonely, he starts, "Let there be light...".

I think as long as you allow for the figments of your imagination to do things that you do not anticipate or even imagine, solipsism is logically unassailable.

Arun said...

To expand on my previous question "Is there any relationship between the classical canonical transformations of the Hamiltonian and modern QFT/string/gravity/gauge dualities? -- when I first learned of classical canonical transformations of the Hamiltonian, I was struck how coordinates and momenta identifiable for a physical system in reality could be transmogrified into equivalent Hamiltonian systems for which a direct physical realization might be difficult to find, so why does nature produce direct realizations of some forms but not others of an equivalent Hamiltonian system? Somehow, not all mathematically equivalent representations are not physically equivalent, in that we experience one but not the other. I have never really understood this well, and now the modern dualities merely compound the problem. And in language now that I didn't know back then, isn't ontological realism challenged even by classical mechanics?

Andrew Wells said...

I would like to take up your challenge, and here's what I've learned after a few years of philosophy(mostly I'm quoting from work I composed earlier). For one experience is axiomatic of a thing; it's an analytic proposition to infer experience from a thing. In order to experience something, there has to be something we're experiencing. The premise experience it's self necessitates or is synonyms with engaging or reacting with something. The philosopher Kant in his day sought to facet rationalism and empiricism together, he made an important contribution [transcendental deduction] to a skeptic neither the existence of an object nor its properties can be certain. The qualia of our conscious experience represents different qualities, the sweetness of wine, the pleasure of sex, the exhaustion of physical activity. These states of existence are secondary qualities, but are distinguished with our own subjective experience so unity of representations necessitates unity of conciousness.

Meaning the conditions of things necessitate the conditions of awareness or experience of those things. Concepts without precepts are empty and precepts without concepts are blind. Experience is not a manifestation of forms, forms give rise to experience not the other way around.

Fizeg said...

The problem I see with a lot of philosophers is that they like too much to discuss simple ideas in terms of complex topics.
That quote reminds me the following. It's possible to describe zebra's pattern both as white stripes on a black background and as black stripes on a white background. That means that zebra's stripes, zebra's hide and zebras themselves can't be considered real. Sorry, that's stupid. Does that interpretation go too far from his original idea?

kashyap vasavada said...

These layers of reality are not very helpful to me. I am happy with the simple (dictionary?) definition of real and non-real. If a thing has properties which are independent of measurements, then they are real. This will make tables and chairs and even the things you cannot see with your eyes like bacteria and viruses real since all of them have unique properties. All the quantum particles (and strings) will fail this test following Bell's theorem and experiments. This is as it should be! How about this definition?

Henning said...

Obviously you just made Holer up because you like figments of your imaginations to agree with you.

Fizeg said...

To elucidate my point about zebra stripes (for you to feel less insolence in my words)
I assume that he's talking about the view that objects of scientific theory correspond to the actual objects and thus scientific theory not only allows us describe observations but also explore the ontology of the world (hopefully I will refer to it correctly as "scientific realism"). Probably he's saying that because of dualities we can't do the latter and have to restrict ourselves to the former.

Then there are two ways to consider the credibility of this claim.
If we take the view that there are some true fundamental objects that are real and everything else "isn't real" (like cloud isn't real, rock isn't real, human being isn't real because all them are composed of more fundamental objects) we don't need string theory to dicredit "scientific realism" because we already had theories with objects that happened to not be fundamental and the same we expect from modern theories. So objects with which theory operate obviously can't be guaranteed to correspond to actual fundamental objects.

However if object is a construct to organize reality with some amount of coarse-graining my analogy works. Then the reality is a whole pattern and distinguishing the object is like choosing to talk about stripes of certain color. The duality tells you that both ways are completely equal. It may happen that at more fundamental level the white stripe will continue to be a proper object while black stripe won't - that what make us consider one more real than another. However duality tells you that both ways may be equally real. Then "scientific realism" is still prosperous.

The only "clever" way I see is if he assumes some unknown actual hierarchy of objects. Like we don't know but we should consider a separate rock as a true object while e.g. a tree isn't a true object. Obviously then we absolutely feeble in our understanding of ontology and there is no point in discussion.

TMEubanks said...

I was fine up to this:

“dualities… are thoroughly incompatible with ontological scientific realism.”


Suppose that a holograph principle is valid. Then there is a something in this description here of a thing (a particle, say) that is dual with something in the other description there (say, an interference of fields on the surface of a lower dimensional hologram). The same information is, by definition, present in both descriptions. Why is this philosophically different than the wave - particle duality we have been living with for almost a century?

In other words, I would argue that "if you have two different fields by which you can describe the same physics," then ontologically they are both equally real, and what is the problem with that? (Or, for that matter, squeamish philosophers can always just declare field A as real, and field B as a mathematical convenience.)

nemo said...

Are virtual particles real?

Sabine Hossenfelder said...

Virtual particles are not as real as real particles.

nemo said...

Their existence is too short to be directed measured, however they can produce real effect. Is it right?

M_Malenfant said...

I guess mostly reality is associated with assuming a unique 'true' description of this reality. My assumption for quite some time is, that sooner or later - or perhaps on certain reality levels - we'll find multiple different physical theories, which are equally 'true' at the same time. Perhaps that is just what duality means. Here I don't regard dualities, which are only due to applying seemingly contradicting interpretations of limimited theories, which can be lifted by a more appropriate one.
Mathematics has already suffered a similar impact with Goedels Incompleteness Theorem.
The question of what reality means then might become even more difficult, if there are aspects of reality existing only in certain inequivalent theories, which can be shown not to be compatible in a single one (also not any still to be found).

JSV said...

I think it might be a distraction to think of "dualities" as being relevant in the sense of two contradictory interpretations of reality. Rather, dualities should be defined in a unified context, with a fundamental definition to define both aspects of the duality. Such unified views usually lead to a more powerful interpretation, where the respective scopes of seemingly limited sub-theories can be understood in more general terms.

With dualities, we should be aiming for a definition within the phase space of the duality, of what reality is, and then find a way of describing its dual (or conjugate) representation, and the transformation (process) between the two. If you've paid attention to symmetries, then the algebra would emerge unambiguously from the duality, and you will have a good description of what reality and physicality are.

For authors in the subject, it's a minefield, because our language is rooted in reality, and everyday words carry unwanted baggage.

p.s. It seems I've been commenting using a Blogspot account I abandoned about 5 years ago.

JSV said...

TEMubanks: "if you have two different fields by which you can describe the same physics," then ontologically they are both equally real, and what is the problem with that?

They would both be a part of the process of reality, but one field would be more accessible or observable (aside: there's also the possibility that fields are convenient statistical abstractions that hide the detail of the underlying reality).

The terms "Epistemology" and "Ontology" are worth comparing in this discussion.

Rastus Odinga Odinga said...

As a professor of mathematics I am always pained by the delusions we have spread among scientists... for example the notion that if something cannot be precisely defined [which means just about everything outside mathematics] then it can be disregarded. I, too, have no precise definition of "real", but I also have no precise definition of the word "dog". From that I do not conclude that it is safe to walk the streets of Manhattan without watching where I put my feet.

Secondly, the idea of equivalence classes [and one-to-one mappings] is another much-abused notion. String dualities put two different theories into one-to-one correspondence. That is interesting and deep, but it is folly to conclude from it that the two theories are identical or equally real or whatever. The integers are in one-to-one correspondence with the even integers. So what? The anatomy of Ed Witten at age 5 was presumably in approximately one-to-one correspondence with his anatomy at present, but the Institute does not hire 5-year-olds. Though admittedly some of the inmates have that mentality....

Sabine Hossenfelder said...


1) I never said that one can disregard things that one does not have a definition for. I just said that I find it pointless to discuss them other than in colloquial terms. We could discuss dogs because you and I both have a vague idea of what a dog is so we share a certain code that to some extent provides a definition. But it would fail in some context. Where, for example, to draw the line between dog and wolf? What I am saying is I find it pointless to discuss this because it's a matter of definition. Sure you could define what you mean with 'dog', eg by listing certain genetic markers, it just would be highly impractical. It might be necessary in some circumstances though. Likewise, I think it's necessary to explain what one means with "reality" if one wants to talk about "reality". Yes, one could just say "it's what most of us think reality is" but that doesn't work for me because I have no idea what you think reality is.

2) The whole point of talking about equivalence classes for the dual theories was to say that they are not 'identical' (as you claim I said) but that they are 'equivalent' in a specific sense, in the sense that is given by the very duality. Re Witten, well, as long as you have a Hamiltonian all space-like slices are unitarily equivalent anyway, though in general not identical.

Uncle Al said...

@nemo, re "Are virtual particles real?"

The Z boson masses 2.4952 GeV/c^2, mean lifetime: 3×10^(-25) sec Propagating at lightspeed (note mass!) that is a 0.01 fm pathlength compared to 1.75 fm proton to 15 fm uranium nuclear diameters. Radius of a hydrogen atom is 2500 fm. Atomic parity violation (single atoms being measurably optically active, always left-handed) arises from virtual Z-zero (neutral current) exchange between the nucleus and an orbiting electron. Is that real enough? (Look up the electron orbital footnote that enables the interaction.)

gazebo_dude said...

Hi Sabine,
I had written a longish comment which seems to have vanished somewhere in submission or moderation. Briefly what I tried to say was that I like the philosophy you present here, but am having trouble distinguishing it from bog-standard subjective Bayesianism. Your "levels or reality" concept seems to correspond directly to Bayesian "degrees of belief" and everything else can be working into that framework pretty straightforwardly, including your comments about inference and dualities. I'm wondering if you see your philosophy differing in any way from subjective Bayesianism and whether would you say that there is no/little point discussing concepts of "reality" above and beyond degrees of belief?

Sabine Hossenfelder said...

gazebo_dude: There is no comment under this name, neither in the moderation queue nor in the spam folder, sorry. It must have gotten lost before submission.

Ron Voigt said...

I had posted this previously on APOD in an open post about anything forum discussion – What is Love?

If the Many-worlds interpretation of quantum mechanics is correct it may not be that far-fetched to both know both love of and love by someone else simultaneously. Should time overlap in those worlds and our lives interchange, we will know what it is to walk in each other's shoes.

"Do unto others as you will do unto you." If shown to be true, the "MWI Golden Rule" would rule with a bit more bite. The mingling of "what it's like to be loved", "what it's like to love others" and "love of self" is worthy to ponder upon. A Universal Ethics of Reciprocity would make hate a fruitless endeavor in a Circle of Life multiverse and the knowledge of love self-fulfilling.
It seems very symmetrical to me that we should all experience life from everyone else's perspective and the Many-worlds interpretation of quantum mechanics might just allow that.

nemo said...

Should we worry about the fact that an object belongs to a mathematical equation rather than belonging to the sensitive part of our world?
My answer is no, at least until the effects are real and measurable.
We should always judge our models depending on whether or not they are able to make reliable forecasts and measurable.
Nature works according to its laws, and not according to our wishes and we have to bend to its phenomenology.
We can not find a reason for everything, but we can test our hypotheses in a scientific way.

Leo Vuyk said...

Dear Sabine.
You wrote about dualism ”I evidently sometimes talk to myself”.
I think that is the key issue of consciousness!!
Because the Big Bang process could be super symmetric,
As a result we are not alone, we have at least one instant- entangled (anti) partner living far away inside an other bubble of the symmetric bubble multiverse called raspberry multiverse.
Max Tegmark already suggested this by writing “is there an other me, reading these lines at the same time?”
In that case, the real world is not what we observe as existing on independent atoms molecules or quanta and solipsism is not the right game in town.
Local experimental entanglement on earth seems to be only the tip of the iceberg and Richard Dawid seems to be on the right track by:
“dualities… are thoroughly incompatible with ontological scientific realism.”
You also wrote:
“I don’t know what “real” even means, which is also why most discussions about the reality of time or the multiverse seem void of content to me.”
“You either must come up with a mechanism that produces the other universes (as in eternal inflation or the many worlds interpretation) and then find support for that…”
(or the multiverse moves to the same class of reality as the number seven, somewhere behind Snoopy and the Yeti.)
I agree fully with you.

Hermannus Contractus said...

I am quite amazed at your remarks on equivalence classes and modular arithmetic, because I share exactly the same perception of reality as you, and I see it as well as composed by many overlapping layers.

I want to note, however, that I think that the question on our perception of reality (something that can be thought as belonging to or addressable by science) and 'making sense of it' (something that in my view belongs to the transcendental realm) are very different things. I am not sure that I understand your remarks on solipsism and your relativitism on what is real. You seem to say that those things that concern yourself more directly are more real to you, which sounds reasonable. However, I cannot agree with this, because I perceive everything that can (at least potentially) submit to God, exactly as real. For me, God is the giver of reality and I think that it is only when we submit to it that we can come to make a genuine sense of reality (as individuals). In my view, the possibility of praying, with which every human being is endowed, makes you exactly as real as me (even if you don't consciously make use of this possibility).

Einstein said that human beings only use 10% of his brain, as if it were possible by their own will to use their whole brain. I think that prayer leads one to use the whole brain, regardless of his/her individual intelligence. Because if God wants to bestow someone with a supernatural intelligence, He can do it. God is the possible infinite, and through prayer one addresses this possible infinite. Thus, for me, to pray is to use the whole brain, and to use the whole brain is reality. In the Bible, the king Solomon prays God asking for discernment, in order to be able to rule with righteousness. God is so pleased by such a request, that endows Salomon with the utmost wisdom in all possible matters. In the Old Testament prayer is found both as praise and as supplication to God. But also waiting is prayer. Having patience is prayer.

I think, the main problem is to want to determine everything by our own will (even when we are). Our internal monologue. I think, we cannot know who we are and we cannot feel or be certain of our reality if we are not somehow as individuals connected to the transcendental. God is there for everyone, and everyone can be also an individual being differentiated from the others but in harmony with the others thanks to its relationship with God.

I consider myself a Christian marxist and I think that marxism teaches how the devil (i.e. capitalism) works (also in our brains) and christianity helps us to oppose resistance as individuals. I think, capitalism throws the individuals to narcissism, desperation and self-destruction (this is what Faust's myth is about), and I feel that it is only through christianity (or jewish religion, in any case a monotheistic religion) that one can oppose it a decisive force drawing joy and resistance from the possible infinite. There are many idols in this world, but all of them are false gods, because they are not the God of Love. I was gladly surprised that Slavoj Zizek expresses somehow a similar view.

Chris Mannering said...

It's quite interesting, reading the comments, how many - very - different appeals there are to the significance of Sabine's comments. Nothing wrong with looks like she had a moment of clarity and managed to get a reasonable amount of it down before it overloaded and went up in a puff of baby-powder. Or that's what happens to mine to anyway.
But it's only because she's a physicist that my interpretation of her points goes straight to hell. No not really. Straight to the work of the physicist Julian Barbour, and more recently Lee Smolin.
At the heart of their nascent 'next direction' search, which is entirely a respectable thing to be doing at the current time given the stasis - something Sabine herself has written about, actually very well. A paper I think titled 'At the Frontier of Knowledge" or something like that.
So at the heart, sits the pure relativistic view of nature. That's where I felt she was either 'at', or on the path toward. Go join 'em...they are onto something.

Stuart said...

What we call "Reality" is virtual.Particles are constantly being annilated and recreated in the next instant in time.What is conserved is information that these particles are carrying which manifests as conservation laws.

Arun said...

Aham Brahmasmi or Ana 'l-Ḥaqq.

Hermannus Contractus said...


As far as one is concerned with 'oneness' and 'unification' every religion/belief is somehow isomorphic to jewish religion. But to me the faithful, irreducible representation of this religion comes with the figure of Christ, who most compellingly reveals the One as Love. For me, the mistery of incarnation in the figure of Christ constitutes the possible connection between our material basis and the transcendental realm. This connection is love: "You shall love your neighbor as yourself" (Matthew, 22:39). Love is so rich, so deep and so irreducible that it cannot be explained by any concept. But, it happens that a person may reveal the meaning of Love through Life. This is the main teaching of Jesus Christ in his lovely commandment above and, most deeply, in the Cross.

I think, the subject of traditional science is occupied with relationships of things where the intervention of God is excluded. It happens that, in the advancement of science, we are growing in concern with ethical issues (because our world is more and more connected and our awareness of our moral responsibility also grows) and with a growing vanity that strives for obtaining knowledge in dark ways (the manipulation of other people in pursuing a certain goal) and that boasts that our knowledge is higher than that of our ancestors. We are building a second tower of Babel and I wonder how can we face the challenge of all our transgressions by excluding the intervention of God, i.e. without having Jesus Christ (or an isomorphism, although I am unable to name any other) as our guide. Ethics, as I understand it, belongs to the transcendental realm. Here I follow Wittgenstein and his famous talk about Ethics, as something more deep in the human being that mere propositions of the natural sciences, in being concerned about what is Good or Evil in a moral sense.

I think together with the late Frankfurt school (the late Max Horkheimer) that theology is very necessary today and that all our decisions and thoughts must strive to have also a theological dimension.

I see in healthy scientific practice many godlike qualities. For example, I think that peer review is a most holy thing, that anonymous reviewers who make an effort to properly assess one paper by reading it and seriously reflecting on it, are like angels. Peer review is a sacred thing that humans contribute to the truth and must be protected against all evil who claims that "peer review is dangerous". I think that peer review almost coincides with science itself, when carried out in a perfectly detached and objective way.

Uncle Al said...

@ Hermannus Contractus : "I wonder how can we face the challenge of all our transgressions by excluding the intervention of God"

We look at the sky and are self-assured we can know how it works - and exploit that knowledge. As for "god," just because it is called "carpaccio de Gambret de boeuf au Napoléon commingeois" doesn't mean we want to put it in our mouths.

Hermannus Contractus said...

>As for "god," just because it is called "carpaccio de Gambret de boeuf au Napoléon >commingeois" doesn't mean we want to put it in our mouths.

I am happy of reading that.

Jeff Thomson said...

Hi B. If you asked a Zen master to prove to you that he was real, he would hit you on the head with a stick. "Is that real enough for you?" he would ask. If you managed to get out a stifled "no", he would hit you again. I think reality hits us on the head often enough that we get that it is real enough. Jeff

David Brown said...

" ... quarks are considered as real as other particles that are easier to measure ..." There might be 3 levels of reality: classical reality, quantum reality, and Fredkin-Wolfram reality. What is the empirical evidence for Fredkin-Wolfram reality? The evidence is space roar, photon underproduction crisis, and empirical findings related to MOND. String theory with the infinite nature hypothesis predicts Newtonian-Einsteinian gravity and some form of supersymmetry (because bosons and fermions need to be 2 different aspects of the same phenomenon). String theory with the finite nature hypothesis predicts Milgromian gravity and Wolframian pseudo-supersymmetry (i.e. bosons and fermions are approximations generated by Wolfram's automaton). Google "witten milgrom". Lestone's heuristic string theory predicts (slightly inaccurately) the value of the fine structure constant. By taking into account uncertainties in the diameter of the Lestone sphere and also the oblateness of the Lestone sphere, it might be possible to accurately predict the value of the fine structure constant.

Wes Hansen said...

"The number seven isn’t “as real as” my shoe, and the reason I’m saying this is because of the physical interaction I can have with my shoe but not with seven."

You can physically interact with seven in a myriad of ways: isolate seven marbles; punch the 7 key on your computer keyboard seven times, 7777777; count to seven using fingers on your hand as reference; etc. The number 7 is as CONVENTIONALLY real as any shoe but neither the shoe nor the seven has any INTRINSIC existence; they are simply distinct emergent forms - epi-phenomena! If you think the shoe has some intrinsic existence which the 7 lacks then I would challenge you to isolate and describe this intrinsic existence; what is it that makes a shoe existence independently of any other "thing"; what makes the shoe exist unto itself; what is the shoe's "self-nature?"

For that matter, what is YOUR self-nature? Is your “self-nature” the “consistent structure” which makes Sabine Sabine? If so then where do you draw the line? Is your existence not somehow dependent on your body and your body’s existence dependent on the existence of heavy elements whose existence is dependent on super novae, etc., etc.? Is string theory the intrinsic self-nature of Sabine?

Another point I would argue is that conventional reality is a COMMUNITY CONSTRUCT, is it not? Spend some time in a mental institution with a group of schizophrenic persons and this will become readily apparent I think. “Consistent structures,” theories, aren’t considered valid until verified by the entire community of researchers, correct? If I look at a chair and say, "Hey, look at that yellow chair," and fifty other people look at the same chair and see a blue chair they're probably going to convince me that there must be a problem with my vision; consistency seems to require consensus.

Anyway, this was a great post which made me think about things a bit. I love the part about the dualities but why would one structure necessarily have to be more “real” than another? Couldn’t they just be two different perspectives of the same epi-phenomena? Perhaps I need to understand the math better to thoroughly appreciate this . . .

With regards,
Wes Hansen

tytung said...

I like your idea of using equivalence class to define "as real as". But I think we also need to have a notion of "less/more real, as compared to..."so that we are able to compare different equivalence classes.
In the case of free-will, as I have commented here before, I suggest we should say that free-will is (at most) as real as the agent (i.e. the person). Both of them are less real than cells, which, in turn, are less real than molecules and atoms, etc.

tytung said...

Also, If we apply the Copernican principle to our theories of the universe, we may need to conclude that our theory of the universe may be just one of the possible theories of the universe. All these theories are equivalent in the sense that they all explains the same universe, but with different ontologies or even structures. This implies there is no one unique theory of everything, but theories of everything that are equivalent but different.
If what is real is defined by our theory of the universe, then there is not one reality but sets of different realities that are nonetheless equivalent, in certain sense.

Stefan Keppeler said...

For what I am concerned, both sides of a duality are equally real, or equally unreal, depending on how convincing you think the inference of either theory from existing data is. They’re both in the same equivalence class; in fact the duality itself provides the equivalence relation.

I'm not quite sure that this argument is in line with your previous reasoning about layers of reality. Suppose you can convincingly claim to have inferred the theory on one side of the duality from experimental data. Then you get to the theory on the other side by means of the duality. Wouldn't that put the latter theory in a different layer of reality? One step further away from direct measurement than the former theory.

Patrick Johnson said...

You still use String theory, the former name for M-theory, repeatedly in most of your articles on the subject.

Chris Mannering said...

Adds to Philosophy? I think you're climbing down with this, because this tacitly reads "the side that's emphasised one concern alone, since the start - string theory or M theory as a nod to the gentleman above, does not predict and cannot predict, ever. Not the way that is meant in science. That this is the side that has gone all out trying to discredit the position, misrepresenting the significance of prediction, trying to have science modified into something that - lets face it - builds in string theory as a permanent theory of everything with no way to throw out, and themselves philosopher kings. Tried standing in close circles talking in loud voices as if this is going to be settled by self-styling as elites. Putting down the public, non-scientists openly as gullible fools that fall for all that silly talk about prediction, committing absolutely unacceptable slurs on scientists that stick in the mud about this little tiny matter. Senior theorists....founders even, dishonestly misrepresenting going on 70 years in which here at the shores at the frontier are more or less where they were at the start. Backing it off to the classical period, which can only be called corrupt and corrupting 'fast one'. That was the beginning...the start where it does take a very long time to get the right basis in place. Hey before the classical period, it took even longer to get a breakthrough...why stop at the classics, go prehistoric! It's dishonest conduct. What matters is that it is happening now at the nexus of science after 400 years of it not happening, and despite an empirical/technological/engineering revolution still blistering away on the back of the vast accomplishments before all this. That's scary and it is a problem. It's not alleviated but aggravated by the fact we don't seem to know enough about the nature of science any more to have the first clue whether science is sickly or not, a cold, cancer, dead already, at the frontier. If science was a patient we're back before fire I should say.
And that's not anyone else but themselves. If there was a philosophical contribution, it's long ago dragged into the mire. It's a dirty rotten betrayal of the scientific dream trying to get a permanent position at the expense of the future of the human race. Shame.

Arun said...

As a physicist, you are some special type of solipsist in that the figments of your imagination are expected to be consistent - consistent as in obeying physical laws.