Thursday, April 17, 2014

The Problem of Now

[Image Source]

Einstein’s greatest blunder wasn’t the cosmological constant, and neither was it his conviction that god doesn’t throw dice. No, his greatest blunder was to speak to a philosopher named Carnap about the Now, with a capital.

“The problem of Now”, Carnap wrote in 1963, “worried Einstein seriously. He explained that the experience of the Now means something special for men, something different from the past and the future, but that this important difference does not and cannot occur within physics”

I call it Einstein’s greatest blunder because, unlike the cosmological constant and indeterminism, philosophers, and some physicists too, are still confused about this alleged “Problem of Now”.

The problem is often presented like this. Most of us experience a present moment, which is a special moment in time, unlike the past and unlike the future. If you write down the equations governing the motion of some particle through space, then this particle is described, mathematically, by a function. In the simplest case this is a curve in space-time, meaning the function is a map from the real numbers to a four-dimensional manifold. The particle changes its location with time. But regardless of whether you use an external definition of time (some coordinate system) or an internal definition (such as the length of the curve), every single instant on that curve is just some point in space-time. Which one, then, is “now”?

You could argue rightfully that as long as there’s just one particle moving on a straight line, nothing is happening, and so it’s not very surprising that no notion of change appears in the mathematical description. If the particle would scatter on some other particle, or take a sudden turn, then these instances can be identified as events in space-time. Alas, that still doesn’t tell you whether they happen to the particle “now” or at some other time.

Now what?

The cause for this problem is often assigned to the timeless-ness of mathematics itself. Mathematics deals in its core with truth values and the very point of using math to describe nature is that these truths do not change. Lee Smolin has written a whole book about the problem with the timeless math, you can read my review here.

It may or may not be that mathematics is able to describe all of our reality, but to solve the problem of now, excuse the heresy, you do not need to abandon a mathematical description of physical law. All you have to do is realize that the human experience of now is subjective. It can perfectly well be described by math, it’s just that humans are not elementary particles.

The decisive ability that allows us to experience the present moment as being unlike other moments is that we have a memory. We have a memory of events in the past, an imperfect one, and we do not have memory of events in the future. Memory is not in and by itself tied to consciousness, it is tied to the increase of entropy, or the arrow of time if you wish. Many materials show memory; every system with a path dependence like eg hysteresis does. If you get a perm the molecule chains in your hair remember the bonds, not your brain.

Memory has nothing to do with consciousness in particular which is good because it makes it much easier to find the flaw in the argument leading to the problem of now.

If we want to describe systems with memory we need at the very least two time parameters: t to parameterize the location of the particle and τ to parameterize the strength of memory of other times depending on its present location. This means there is a function f(t,τ) that encodes how strong is the memory of time τ at moment t. You need, in other words, at the very least a two-point function, a plain particle trajectory will not do.

That we experience a “now” means that the strength of memory peaks when both time parameters are identical, ie t-τ = 0. That we do not have any memory of the future means that the function vanishes when τ > t. For the past it must decay somehow, but the details don’t matter. This construction is already sufficient to explain why we have the subjective experience of the present moment being special. And it wasn’t that difficult, was it?

The origin of the problem is not in the mathematics, but in the failure to distinguish subjective experience of physical existence from objective truth. Einstein spoke about “the experience of the Now [that] means something special for men”. Yes, it means something special for men. This does not mean however, and does not necessitate, that there is a present moment which is objectively special in the mathematical description. In the above construction all moments are special in the same way, but in every moment that very moment is perceived as special. This is perfectly compatible with both our experience and the block universe of general relativity. So Einstein should not have worried.

I have a more detailed explanation of this argument – including a cartoon! – in a post from 2008. I was reminded of this now because Mermin had a comment in the recent issue of Nature magazine about the problem of now.

In his piece, Mermin elaborates on qbism, a subjective interpretation of quantum mechanics. I was destined to dislike this just because it’s a waste of time and paper to write about non-existent problems. Amazingly however, Mermin uses the subjectiveness of qbism to arrive at the right conclusion, namely that the problem of the now does not exist because our experiences are by its very nature subjective. However, he fails to point out that you don’t need to buy into fancy interpretations of quantum mechanics for this. All you have to do is watch your hair recall sulphur bonds.

The summary, please forgive me, is that Einstein was wrong and Mermin is right, but for the wrong reaons. It is possible to describe the human experience of the present moment with the “timeless” mathematics that we presently use for physical laws, it isn’t even difficult and you don’t have to give up the standard interpretation of quantum mechanics for this. There is no problem of Now and there is no problem with Tegmark’s mathematical universe either.

And Lee Smolin, well, he is neither wrong nor right, he just has a shaky motivation for his cosmological philosophy. It is correct, as he argues, that mathematics doesn’t objectively describe a present moment. However, it’s a non sequitur that the current approach to physics has reached its limits because this timeless math doesn’t constitute a conflict with our experience. observation.

Most people get a general feeling of uneasiness when they first realize that the block universe implies all the past and all the future is equally real as the present moment, that even though we experience the present moment as special, it is only subjectively so. But if you can combat your uneasiness for long enough, you might come to see the beauty in eternal mathematical truths that transcend the passage of time. We always have been, and always will be, children of the universe.

74 comments:

Uncle Al said...

A perm chemically reduces crosslink cystine bonds, R-S-S-R to uncoupled cysteine R-SH HS-R. Reconfigure the hair, then oxidize to close new crosslinks to hold the configuration.

http://en.citizendium.org/images/thumb/a/aa/Cysteine_vs_Cystine10.jpg/350px-Cysteine_vs_Cystine10.jpg

The process weakens and embrittles hair, and degrades its natural or added color.

Space is localized. We perceptibly translate at will. In like units, ct is a very long dimension and difficult to dent. There is no apparent re-entering the past and no venturing into the future then returning. We have no test of butterfly wings changing a trajectory. However, one does not bet on "hard eight," even in the multiverse.

Edwin Steiner said...

I'd like to point out that this problem is not specific to time. One could in the same sense speak of a problem of the "Where" or of the "Who": Why am I experiencing my experience and not that of the other person in the room?

Objectively this question is probably empty. If we describe two people in a room, we could say that thought processes are locally correlated in a similar way as you phrased it for memory correlations (without an arrow in this case), and that there is no problem with two peaks of such correlations being equally there but separated.

However, this does not answer the subjective question "Why am I this peak and not the other one?" (And your post does not answer the analogous question "Why is my Now now this point in time and not another one?") My guess is that such questions will turn out to be meaningless when (if) we eventually understand what consciousness is and how it works. The interesting thing will be to understand precisely what is wrong with these subjective questions, but I think we are far from that point.

Bar said...

Nicely put. Generalizing your statement: "the failure to distinguish subjective experience ... from objective truth" is an observation that becomes true in many human undertakings.

L. Edgar Otto said...

The spacious Now remains an interesting question whether it a meaningless one or not.

I
On the sundial in the rose garden with a plaque quoting Helen Keller (and what does theory originally mean but something like vision or perception - that tree perhaps that is not there if nothing or no sentient thing observes it to hear it), are bronze letters around it saying two things at any instance seems to me both naively true.

Today is Yesterday's Tomorrow &
It is Always Morning Somewhere in the World

"We can see into the future only to the extent we can see into the past" some conclude from QM theory or "A star whose light from a billion years ago does not exist until one sentient sees at least one photon of it " from that they conclude we can change the past.

QBitism is a good word in the present issues of quantization and information thus discrete or continuity questions.

I personally lean toward such questions as to what in subjectivity has demonstrated effects will not prove meaningless albeit a more complete treatment as a spacious mathematical triviality.

I agree that this may have been a cautious but initial blunder that also casts a long emergent theory shadow and on the grounds Sabine cites

The Spacious now paradox (not necessarily a contradiction) is that time or entropy cannot be defined in a closed system if in the interface between continuous and discrete models we cannot define a closed system. Is a proton immortal?

Don Lincoln has an article coming in May (I am holding his book from my philosophy chat forum days as The PeSla - a useful book by someone at Fermi Lab describing the LHC.)

I had forgotten I posted on Sabine's blog and existentialist (pragmatic not postmodern surrealist I am) it is surprisingly long ago for my emerging wisdom reading this constellation of bloggers.

You might say by reawakening my memory from its compact hidden dimensions we have a past that finds itself in the Here and Now again by which even an abstract over plane of symmetry as a reference frame does not yet resolve these important issues as physics.

Arun said...

" That we do not have any memory of the future means that the function vanishes when τ > t."

-- Have we introduced this time-asymmetry by hand?

Arun said...
This comment has been removed by the author.
Arun said...

Introduce a function e(t,tau) which encodes the memory the environment has at time tau of the particle at time t.

Maybe if you can prove some general properties of e(t,tau) that are strong enough, you can figure out quantum mechanical time evolution (I mean "measurement" vs "unitary evolution) and what happens to blackholes.

L. Edgar Otto said...

Arun, which hand? It seems three space cannot separate prime but different pairs without 6 of them and that is if we can imagine highly curved dimensions in a lattice of QM GUT over endless scales as all there is of everything. Nature does it and we like her make the same blunders which is of course who wins the theory chess game. The loser being the last one to make a blunder in the now.

CapitalistImperialistPig said...

In my opinion you have merely formalized the statement of the problem of Now. Nothing in physics corresponds to your function f(t,tau) - or more precisely, to your tau.

Plato Hagel said...

Hi Bee,

Our Cogito model simply identifies the source of randomness as the inevitable noise, both thermal noise and quantum noise, that affects both proper storage of information and accurate retrieval of that information at later times. These read/write errors are an appropriately random source of unpredictable new ideas and alternative action possibilities.

I think we sell ourselves short as to our capabilities, and from that we say subjectivity, yet the idea of a Now is very capable of many possibilities. Why, anyone in particular and Lee Smolin points this out in our interpretation of the atom?


I suspect that will, qualia, meaning and intentionality will turn out to be understood to be aspects of nature. But I suspect that by the time we have achieved this our understanding of nature will be quite different. That is, I suspect that we will only succeed in reducing minds to atoms when we have revolutionized our understanding of atoms in some way presently inconceivable.

I only have an intuition about the first step in this process, which is to bring time and the present moment-the now-into science and make it central to physics and prior to law. By embracing presentism and the openness of the future we radically recast the context for understanding what it means for anything-rock or atom or mind-to be part of nature. Lee Smolin


Best,

Plato Hagel said...

In 1952, in his book Relativity, in discussing Minkowski's Space World interpretation of his theory of relativity, Einstein writes:

Since there exist in this four dimensional structure [space-time] no longer any sections which represent "now" objectively, the concepts of happening and becoming are indeed not completely suspended, but yet complicated. It appears therefore more natural to think of physical reality as a four dimensional existence, instead of, as hitherto, the evolution of a three dimensional existence.

Robert L. Oldershaw said...


P. Woit: "...it might be a good idea to spend time obsessing about conformal symmetry, while knowing that conformal symmetry breaking is required to make it work, and we don’t (yet) have a good enough idea about conformal symmetry breaking."

G. Ellis: "- right on. This is a very promising direction."

RLO: "Hmmmm"

Florin Moldoveanu said...

Embarrassingly, I admit I have a knowledge gap: I don't know what exactly was "Einstein’s greatest blunder".

Was it:
(a) the introduction of the cosmological constant?
(b) the faulty reasoning that the cosmological constant leads to a steady state solution?
(c)the later rejection of the cosmological constant based on experimental observations?
(d) another explanation.

Sabine Hossenfelder said...

Edwin:

"Why is my Now now this point in time and not another one?") My guess is that such questions will turn out to be meaningless

The question is meaningless because you can ask that very same question in any moment. All your 'nows' are the same in that they all feel 'now' in some moment. Thus the question why it's not some other now is pointless. The relevant question is why, if you experience one moment as 'now' are the other moments not 'now'. Best,

B.

Sabine Hossenfelder said...

Florin,

Einstein's greatest blunder is commonly said to be the cosmological constant. It goes back to a quotation that is attributed to him in which he refers to it in that way. However, for all I know this quotation has never been confirmed. Best,

B.

Sabine Hossenfelder said...

Arun,

As I wrote, the time assymmetry goes back eventually to the question why the universe started out at an entropy so low it's still increasing. If we'd be living in thermal equilibrium the past would look the same as the future. Alas, we don't. Just why that is so is a puzzle indeed, but it's a question distinct from the 'problem of now' which is explicitly about experience.

Regarding the question of the memory function, I don't think that human memory will be well captured by any fundamental physics constraints on this function. Eg, it shouldn't only vanish in the future but also outside the past lightcone, but in practice that has little relevance. Maybe one could try to use it as a phenomenological model. Best,

B.

Sabine Hossenfelder said...

CIP,

To begin with, exactly what the function is doesn't matter. The problem is allegedly that it cannot be captured by physics and that is plainly wrong. Second, this function surely exists, you can explicitly construct it for simple systems. If you don't like the example with the perm, think of metals or plastics that can 'remember' a shape. You can very well quantify just exactly how well they recall that shape after some time, depending on various environmental variables, etc etc. Best,

B.

David Brown said...

"... the failure to distinguish subjective experience of existence from objective truth ..."
"What is measurement? Why does measurement exist?"
What does dark matter mean in terms of measurement? What is the fundamental relation of measurement to objective truth?

Arun said...

"Regarding the question of the memory function, I don't think that human memory will be well captured by any fundamental physics constraints on this function."


---- E(t,tau) for a system is the memory the **environment** (not human memory) has at time tau of the system at time t. For a system undergoing unitary time evolution I think E(t,tau) is negligible for tau not equal to t (except perhaps for the gravitational trace of the system). A quantum mechanical "measurement" would leave a memory trace in the environment, I think.

When a black hole swallows a particle, does all memory of the particle vanish from the environment? etc., etc.?



Amrit Sorli said...

ETERNITY IS NOW

Uncle Al said...

A unique strong arrow of time occurs in chiral universes. No entropy and law of large numbers appeals are necessary.

Nature 463 210 (2010)
Phys. Rev. D 71 057501 (2005)
Phys Rev Lett. 91(24) 247404 (2003)
Chem. Phys. Lett. 173(5-6) 485 (1990

Jochen said...

The argument regarding the memory of certain systems is circular: they recall some state at a given point in time better than at another because their 'now' at that point in time is closer to that state than their 'now' at the other (later) point in time. But what makes one 'now' different from the other, i.e. what makes one as opposed to the other the subjectively experienced current now, is exactly the problem.

Basically, the problem is that your τ is a function of t---it doesn't give you any new information: the memory now of a given moment in time is different from the memory of that moment at some other moment, because the now is different from that moment. The question is not, 'why does my experience at some given moment differ from my experience at another moment', but rather, 'why am I experiencing this particular moment as opposed to that other moment'.

In philosophy, quantities such as that elusive 'now', and others like 'here' or 'I', are called indexicals (for obvious reasons for once). The more general form of the problem (if it is one) is then that the physical description of the universe does not fix indexical facts: the quantum state of the universe does not include a pointer to a particular time as being the one experienced, nor does it single out a particular viewpoint from where you look at the universe, etc. Using that quantum state, you can't answer the question 'what time is it?'.

You can answer related questions, such as 'where are the pointers of this clock pointing when that subsystem is in this state', and so on; and this is, in fact, something like what your f(t,τ) ('what is the memory of this moment (τ) at that moment (t)?') achieves. But notice that in this answer, lots of words like 'this' and 'that' had to be used, which once again are indexicals, and thus, the problem just is iterated.

Furthermore, it's not obvious that you can rephrase all the relevant questions about indexicals in such a 'relational' way (the relations between the fingers of my right and left hand are the same, but right and left hands are different objects, thus such a description may leave out salient features).

It all comes down to there not being any distinguished 'point of view' present in the quantum state of the universe; to use it to describe what you're experiencing at a given moment, you have to supply it yourself.

Jerry Lisantti said...

Your function that you give for memory is interesting. It makes me wonder what kind of function, if any, do those that model the brain using either computers or hardware use for describing individual neurons and their connectivity. Memory I suspect is a result of a cluster of neurons and their connections. Some sort of mathematical model should be able to describe a neuron and its connections and then have a cluster of neurons "show" memory. That system should also be scalable.

Arun said...

"The question is not, 'why does my experience at some given moment differ from my experience at another moment', but rather, 'why am I experiencing this particular moment as opposed to that other moment'. "

Answer: the only reason why you know you're experiencing this moment and not that other moment is the state of your memory.

L. Edgar Otto said...

What time is it?
One answer is the time is Now. Like in the simple clock illustration above only physical wave functions begin with three generations of axial hands.
Uncle Al is right even if the arrow runs backward as well. But chirality begins at 9 dimensions as if stacked tetrahedra. The strong resulting arrow as inertia can be interpreted as gravity or as mass in back reactions.
Bergson while not regarded a deep philosopher had this simple distinction of time and duration. One could be interpreted as subjective like Leibinz and atom like nomads.
Memory is stored in the abstract structure of vacua beyond the QM uncertainty- not all the scientific picture once past the standard theory.

Unknown said...

Great post. I am reminded of a book that was very influential to me, back in the day:

The Remembered Present, by Gerald Edelman.

...who is a neuroscientist, and this is his theory of consciousness. So this notion of a subjective now preceded by a decaying memory of previous events is certainly very current in neuroscience today. The hippocampus and surrounding cortex are believed to be responsible for this sense of the 'remembered present'. Look at famous amnesics like H.M. (Henry Molaison) or Clive Wearing. They live(d) in an eternal Now, and their brain damage included the medial temporal lobe, exactly where the hippocampus is located.

Mark Avrum Gubrud said...

The past isn't real, it was. The future isn't either, it will be, but is not yet.

Somehow physics (if it must account for everything) must account for this.

Also, as you know, in a block universe, nothing ever happens. I think a lot of physicists find this psychologically comforting, but what would be the point of such a universe?

I think a lot of physicists want to impose mathematical "beauty" on nature, when rather mathematics must be forced to describe nature.

But of course, relativity long ago banished simultaneity, and with it the naive concept of Now.

It seems to me that there can be a local now, each localized system propagating through your spacetime and broadcasting to the other objects its random choices. If the regional temperature is low enough, there can be quite an extensive now, as objects can then exist and share a common frame. Conversely, if the temperature is too high for anything to exist that could measure a flow of time, perhaps there is no now there.

I believe that I am alive now and that what has died and been erased (reduced to indecipherable noise) no longer exists. I also think my future is not determined in the now, and therefore cannot exist either. This of course implies again the same thing about my past.

But of course, I am an experimentalist, not a theorist.

Jochen said...

Arun: "Answer: the only reason why you know you're experiencing this moment and not that other moment is the state of your memory."

But the state of my memory is a function of time; what its state is depends on what time it is now.

The problem is that with sentences such as "We have a memory of events in the past, an imperfect one, and we do not have memory of events in the future.", one presumes the notion of now, since the notions of past and future depend on it.

Sabine Hossenfelder said...

Jochen,

What you say is incorrect. Memory does not presume the notion of a now, it presumes an arrow of time. It is the arrow of time that generates the asymmetry between past and future - at any point in time, not at any particular point. Best,

B.

L. Edgar Otto said...

Unknown (or whatever indicator we agree on in these issues of privacy by spacious observation including Anonymous) the connectionist hardware of our nerve net system does appear confirmed as a hierarchy of a holographic system.
If we in ultimately random paths whatever the stastisical interpretation ask on what peak experience is to be consulted here and now isolated locally as events - what some claim illusion, QM can see all electrons as but one or in the universe there has to be at least one monopole. Either way philosophy does not escape a trivial and still picture we are just talking to ourselves.

We cannot see absolute points jumping between trajectories if it is not part of a dynamic moving picture. Nor that one shielded in autonomy may be influential if not essential in actions at a distance appearing timeless in any case.
We have hierarchies of control be they a higher system of nerves or things like DNA or genomes and epigenomes.

Perhaps QM computation will be a modest improvement and stored memory epheremeal will not soon vanish or decohere.

If QM works as some imagine then it may not be about something like prayer or ESP, but if we sort out familiar subjective time perception and can monitor the processes materially why considering this non problem can our minds directly not connect to the quantum cloud built as a mainframe?

How likely is it anyone will remember David Mermin? Einstein on this matter made no blunder but the frontiers of his time was rather spread out.

As to math it should appear to us now that what can seem ugly in symmetry from a little higher view of nature may be beautiful which ever way time may unfold from the Flatland between the universe on either side and our dreams.

Edwin Steiner said...

Sabine:
"The question is meaningless because you can ask that very same question in any moment."

I agree that the question is meaningless in any sense in which it can be made objectively precise. As you point out in your post the "Problem of the Now" becomes quite trivial then. I have a really hard time believing that Einstein missed that. He had a good command of statistical physics and a correlation function that peaks in the near relative past would surely have occurred to him, I guess.

From what little information I have, I'd speculate he was wondering about our subjective experience of a certain time and place being somehow "selected" by/for our consciousness. (I'm afraid I cannot phrase this in a more meaningful or well-defined way.)

There is a quote by Einstein regarding consciousness:

"Ein Mensch ist ein räumlich und zeitlich beschränkter Teil des Ganzen, das wir "Universum" nennen. Er erlebt sich selbst und sein Denken und Fühlen als getrennt vom Rest in einer Art von optischer Täuschung seines Bewusstseins."

For me it is one of the most interesting questions how exactly this "optical illusion" of consciousness comes to be.

Mark Avrum Gubrud said...

Also, your point seems to be that physics can "capture" the subjective experience of flow of time and the specialness of the present by writing down f(t,τ), but it isn't clear to me that this solves anything; I have memories from when I was 4 that are clearer than anything from last week, and in general the "memory" of past events or configurations is not just a function of time but of what other events intervene, so really it has to be f(t,τ, everything else), which doesn't seem very useful.

But also, has there really ever been any problem understanding that, in the block picture of spacetime, where you imagine yourself standing outside and looking at the frames of the movie, in each frame the characters have the subjective perception of being in a present moment and of time flowing?

The real question is, it seems to me, not whether this picture is compatible with our subjective experience, but whether it is actually true (whatever that means). I am not just playing games with words when I say that it is incorrect to say the past and the future also exist. They do not exist in the present. They are not even determined by the present, neither the future nor the past. Quantum indeterminism works both ways.

Now, I understand that you believe quantum mechanics actually rescues determinism, in the form of the unitarily evolving wavefunction. But as we look in each direction of time, that unitary evolution tells us less and less about what actually will or did occur.

Many theoretical physicists are so uncomfortable with the idea of indeterminism that they believe in Everett many-worlds, but this is again a super-block universe in which nothing ever happens, because everything does.

It seems to me that the present moment is the moment of decision. This is, at least, such a clear feature of the world as we experience it that it seems to me physicists should try to force it on the theory rather than the other way around.

This is of course nothing new. Collapse of the wavefunction cannot be just something that happens once in some lab experiment. It is something that must be happening continually everywhere as the things that exist in the universe make their allowed random decisions, consistent with the Born probabilities.

Forgive me if I find this metaphysics more plausible than the idea that each random decision of each thing induces a multiplication of the whole rest of the universe. The idea of chance just really doesn't scare me that much. I believe shit happens.

Don Foster said...

Thanks for the provocative post on the problem of Now and its ancillary notions.

Now I will spend some time considering my general feeling of uneasiness upon realizing that the block universe implies all the past and all the future is equally real as the present moment, that even though I experience the present moment as special, it is only subjectively so.

You may assign some probability to the event of my defending subjective experience.

Best.

L. Edgar Otto said...

Let us assume based on one concept from QM theory that anything can pop out of a black hole information wise. If there is one monopoles in the universe what would be the result if another one popped out?

Euclid way back decided the parallels not meeting was a postulate so this speaks for a wider view of whatever logic he was using. Logic is not shown to map to arithmetic.without raising paradoxes. Euclid moreover in his hymn to the universe as the Platonic dodecahedron cannot be assumed if he brought up to date the universe is finite or infinite- it logically is a Flatland by Pythagoras on which we imagine models with defects such as where curvature fits into our models.
Sabine is right, as you say, that QM saves determinism again. It also saves Newtonian concepts and scales. But it is possible like particle physics of a hierarchy of types (Russel) that above this superdetermism the universe can become indeterminate again.
While the information as a time line can exactly equal that say in a non linear plane (or brane). We can imagine the universe (distinguishing many world and multiverse with Flatland between them) that beyond the symmetry questions of the standard model that types can be successive or onion like as the same box description.

We imagine otherwise and debate objectivity. because there are a few equivalent viable states as choices much like neutrinos changing flavors

Gravity or Mass stands alone in the GUT and in its own superflatland is time as linearly dynamic without the need for inflation to average things out or confuse questions of entropy equivalent to the zeroth thermodynamic law. In a sense Einstein found an aether again and suggested we may as well use it as a general term.

Assuming there is an absolute or Flatland box our rather universal sense of sublective time should be on one side of our dreams IR the other for in both we can view ourselves as from outside or as actors experiencing the sequence within a dream.

There are similar issues that apply to social gravity and laws. Decisions are a local emotional process and there is no such thing as an impartial juror or for that matter peer review. We see the speaking not see the truth. This is called "Defensive Attributation" and is right up there with cognitive dissonance and other self delusions.
This comes after the presumption of guilt and plea bargaining to load dice before a trial. After the standard model should physics really enlighten us in how we should guide our future world and our evolution. Social polarization has no biceps save for the Now as someone else's problem not the status quo.

Georg said...

"" No, his greatest blunder was to speak to a philosopher named Carnap about the Now""
Hello Bee,
do You see the problem in philosophers in general or
in the person of Carnap?
Regards
Georg
BTW,
when You inscribe the clock with the German "nun", You get higher resolution without using more letters.:=)

Sabine Hossenfelder said...

Georg,

My comment about Einstein's blunder wasn't meant too seriously. It is supposed to say that people generally, not philosophers in particular, overinterpret the words of Einstein and other idols. Maybe Einstein was just thinking about this point this one day over lunch just as that philosopher was visiting and that was enough to produce volumes of books about it. How much worse can worshiping get? Best,

Sabine

Jochen said...

Bee, I'll have to disagree. The content of my memory is its content at a particular point in time; without specifying that point in time, there's simply no meaning to my memory's content.

I'll grant you that the arrow of time creates the asymmetry between past and future at all points in time (in fact, it *is* that asymmetry), but what is in the past, and what is in the future, is a function of the moment in time we're looking at. Since you're presuming that this issue has already been settled, your answer is circular.

You basically say it yourself when describing your two time parameters: "t to parameterize the location of the particle and τ to parameterize the strength of memory of other times depending on its present location."

The dependence on the present location is nothing but a dependence on the particle's now, since the present location is just where it's at now.

Of course, you could specify a time in the past and a 'strength of memory' (though I'm not sure that's a very good model---memory is generally more complicated than that), and get out a present moment. But all you've done then is to reformulate the problem of the now as a 'problem of the strength of memory of an event in the past'---you've changed the variables, but made no headway on the problem.

Jerry Lisantti said...

I guess the question simply is how do we incorporate our subjective experience of now in time with the objective physical universe's time? Does this mean how do we incorporate our conscientiousness into physics? Didn't Wigner, Schrodinger and other's work on this problem with respect to quantum mechanics?

joel rice said...

sounds like GFR Ellis and Tony Rothman discussed this in
quant-ph/0912.0808
and 2 later articles.

to paraphrase - the arrow of time arises because the future has not yet happened.
ie - the local future is just possibilities, and Weyl was 'reifying' classical spacetime - which does not care about possibilities.

DocG said...

Mallarme already solved it:

Un coup de dés jamais n’abolira le hasard


To be translated as follows (in future):

The retrospective eventing of the event will never constrain the projective momentum of the moment.

Arun said...

Jochen,
People who have had a brain injury and have lived for many years but can't remember 20 minutes ago have been studied. It takes some extrapolation to imagine someone who has lost even immediate memory (probably couldn't function) but that is why I wrote (the experience of the subjective now) "depends on the state of your memory".

-Arun

Jochen said...

Arun, actually it seems to me that the possibility of complete anterograde amnesia refutes the idea of memory being necessary for the experience of a now: while they would be constantly confused as to what happened a moment ago, they would always be confused in a subjectively experienced now.

They might have thoughts of a propositional content such as 'I don't know what happened a minute ago', but I don't see how they would not experience those thoughts as occurring to them in a given present moment, and this experience is what is in need of explanation.

L. Edgar Otto said...

Jochen,

You seem not very aware of studies on how we experience subjective time.

Do we not have to sleep and dream to turn short term into long term memories?

How is it that in the terrible two's of night terrors we lose half our nerve connections?

When falling subjective time speeds up to clock time.

Initial memories are closer in early memories as say you at 4 years old than say the last two weeks.

One can recover hidden and forgotten memories back past the latency period.

Some people remember everything adding to the subjective now. Brick layers can recall under hypnosis every speck of defects from ten years ago

In deja vu the tenth of a second delay between brain hemispheres is thought to explain the feeling "we have been here before."

Part of dreaming is the culling and over writing of memories. There can be false memories set down.

The body memory in DNA can show various cells have the same measure of time as if a changing but universal Now.

Is the quantum cat aware if it is dead or alive?

With 15 seconds of memory does a goldfish think its small aquarium endless and extends a little outside the tank?

When looking at a small screen a half hour of sublectivr time can seem five minutes of clock time. We feel small at first under the canopy of stars.

The distance toward an object we are moving toward seems shorter than other directions.

When young Einstein pushed his baby's. Pram along the Zurich Zero it must have occuref to him to consider it objectively that the lamposts really did shrink or expand as he approached them never reaching more than the height when close or vanishing forever into the distance.

Jochen said...

I'm sorry, but I think you're missing the point somewhat. All those minutiae about human memory are interesting, but irrelevant: the question is, why am I experiencing this particular moment, why is my now 15:18, 21.04.2014, rather than any other point in time?

And the problem (if it is one) this poses for a physicalist understanding of the world is that there is nothing special to the point in time that you experience as now: the quantum state of the universe does not tell you what time it is. Bringing in memory doesn't help, as it's already predicated on a given moment being now, separating past (rememberable things) from future (nonrememberable things).

For the record, I don't believe this to be a serious problem for physicalism, and I don't even think most antiphysicalist philosophers do (such as David Chalmers). But I don't think that a physical answer to the problem of now is even conceptually possible.

L. Edgar Otto said...

Jochen,
then why are you so certain of yourself? A whole or subjective and objective being that misses each others point?

Do we see the shadows delayed on Plato's. Cave wall, a reflection of ourselves, or see through the glass aquarium box walls into the dark indeffinitely?

Do we drink of the water or the wave and can we taste the difference? Can we face the freedom of a god who loaded the dice and walked away?

Between the plastic in its vaporous dreams and stone compressed fixed and dense we ride the light, electrons over metal deeper time.

It might have been. It may as well have never been for now I have nothing more to tell you. Enjoy your thought as I choose to think of philosophy and science I fancy I can tell the difference.

I respect your views of emerging truths if but a partial picture forged in lies, damn lies, statistics, and now string theory.

Sabine Hossenfelder said...

Jochen,

" The content of my memory is its content at a particular point in time; without specifying that point in time, there's simply no meaning to my memory's content."

There is no problem specifying a point in time if you have a metric manifold. You can do this in any (sensible) physical theory we know of (let me not get started on 'relative locality'). The problem isn't specifying a point - here is a point: (x,t). The problem is that there is nothing special about this point. It becomes special subjectively due to the memory function at this point: it decays away from t. Best,

B.

Sabine Hossenfelder said...

Jochen (again),

"the question is, why am I experiencing this particular moment, why is my now 15:18, 21.04.2014, rather than any other point in time?"

No, you are mistaken, this is *not* the question, please read what I wrote. The question is why do you think in that 'now' (15:18, whatever) that this 'now' (15:18, etc) is "special". That is not the same question. Best,

B.

Jochen said...

It's to the best of my understanding the question that philosophers mean when they are talking about the problem of now. And in any case, it's certainly a valid question to pose.

The thing is, there's a set of quantities---the indexicals---that pick out my experience from all possible experiences; and the question is why those indexicals would have the value they do, i.e. would point to where they point. Why (or even how) is this possible experience picked out and made mine above all other possible experiences?

I think the standard thinking on this issue is as formulated in the paper by Chalmers and Jackson, "Conceptual Analysis and Reductive Explanation". There, they lay out a basis from which, on a reductionist conception, all truths about the world ought to be derivable, and which at minimum contains all physical truths, a 'that's all' statement to the extent that there are no further, nonphysical entities, and a set of indexical truths not derivable from this objective description (exactly by virtue of it being objective). See also the wiki page on physicalism: http://en.wikipedia.org/wiki/Physicalism#A_priori_versus_a_posteriori_physicalism

To me, thus, the attempt to give a physical explanation for the subjectively experienced now is the attempt of explaining from physical facts the value of a given indexical, namely that denoting the present moment. This is, in a sense, a category error, trying to derive a context-dependent quantity from a context-free, objective description of the world; and upon re-reading, maybe that is what you wanted to point out when you wrote that the problem is one of failing to distinguish between subjective experience and objective truth. If so, then I agree; but I'm not sure I then see any problem left that ever greatly worried anybody.

hush said...

How much worse can worshiping get? Best,

Sabine.

I dunno.

We love who we are. And what we do.
And what we say. And others.
O.k., well, most of the time.

Really, I am terrified to give you the details of your being, specifically your memory and learning.

Imagine your own disappointment as well as all of your readers disappointment upon reading how close a perm is in simplicity to memory and learning and, ah.. truth.

Demystifying, unraveling, untangling and setting paths gone astray straight again to all who have commented here.

As I said above before, we love what we say as well.

You love truth too. The truth will stifle all the prose, adoration, and words of worship your readers use for something as simple as a perm.

Well, readers, you know what?
Memory and learning is as simple as a perm.

You are all that simple.
You are all that special.
You are all that subjective.

It's time for me to go again.

Before I go - your 'learning'
and 'memory' is 'created' from DNA repair. All life as you know it repairs itself. This dovetails into all physical law and explains literally all the comments here.

Necessary, sufficient and last, but not least, incomplete for you.

pete said...

Excellent article. I think some readers have missed the point of what you were saying, but I see you've addressed that in the comments.

Georg said...

"" How much worse can worshiping get?""

Hello Bee,
right NOW, NASA names a lot of pebbles
alongside curiosities way after some
heros .
But of course:
Ruhm, wie alle Schwindelware, hält selten
über 1000 Jahre :=)

Phillip Helbig said...

Most people think of themselves looking forward when moving into the future, like looking through the windscreen of a car. But, as Robert Pirsig points out, the Ancient Greek concept is actually more realistic: you are standing still, not moving; the future comes up from behind you. Standing still while time passes you by is a much better metaphor than actively moving into the future, since we don't control the speed. And the future coming from behind is more realistic as well: we don't really know anything until (at the earliest) just after it has happened, i.e. until after it has come into view when overtaking us. Also, we are continually looking into the past, with memories generally fading with time, like a parade passing us by.

Sabine Hossenfelder said...

Jochen:

"It's to the best of my understanding the question that philosophers mean when they are talking about the problem of now. And in any case, it's certainly a valid question to pose."

You can ask whatever you want to ask, but is not a scientific question because it's void of content - it is meaningless vocabulary. The experience that you have is that the present is special. But you have this experience in *every* moment. Now. And Now. And now again! There is absolutely no observation and no evidence that any of these moments is special in itself, which is what you are after. What is special is only your perception of that moment. Think about this for a moment and note the difference. My argument is explicitly about the experience of the present moment as special, see quote from Carnap. Best,

B.

Jochen said...

If every moment is special, then of course, none is; but then, every moment should be the same, but they aren't: at any given moment, I experience that moment to the exclusion of any other. All of these moments are equally special according to your prescription, but nevertheless, they manifestly do not stand on equal footing. If they did, I should experience them all the same; but I don't, I only ever experience one.

This is the problem of now, such as it may be: not that my experience at any given moment is special, but that I have an experience of a given moment at all. The explanandum is the situatedness of my experience, where there seems to be no principle that picks out just *where* (or when, etc.) it is situated. There's a little arrow that points to whatever spacetime event happens to be the center of my experience, a variable 'here_now' whose value has to be specified in addition to e.g. the quantum state of the universe in order to pick out the experience I am having right now from all the experiences I could be having (or that could be had, if the I itself is just such an index).

My experience could just as well (as far as the complete set of physical facts is concerned, i.e. say the complete block universe) be that of going to work this morning, but it isn't; and typically, where different matters of fact could obtain, but only one, in fact, does obtain, one looks for an explanation that singles out the actually obtaining facts, i.e. an explanation for why I am not in fact having the experience of going to work this morning (or tomorrow morning).

I mean, there's clearly a fact of the matter regarding what experience I have, and also, how that experience differs from other experiences I could have; this is, certainly, not meaningless or void of content---to the contrary, it's the most immediately meaningful thing we have access to. But if I have one experience as opposed to another, then either there's a reason for my having that experience rather than another (which is what the problem of now asks for), or there's none, in which case it's just a brute fact that has to be added to a complete set of physical facts to derive from it the salient features of my experience.

Don Foster said...

"The prudent mariner will not rely solely on any
single aid to navigation."
-- Coastal chart legend, U.S. Coast Guard –

I was delighted to find that Einstein was a bold but imprudent mariner. He loved to go out sailing in stormy weather, was dismasted once and twice needed rescue. He did not swim, but refused to carry a life vest.

I wonder how he would reconcile his experience of breasting the waves, hands on rope and rudder, with the notion that actions of the present moment do not have real consequence in determining future events.

Or, do I misinterpret the implications of the block universe of general relativity?

Best.

hush said...

When Planck introduced his "act of desperation" he solved the black body radiation problematic of the never-ending-story of accuracy from never-ending experimental data.

Einstein showed Planck the implications of his desperation five years later within a theory of special relativity.

What a perm is for you today will be a theory of the mind in five years from now.

Of course you don't see the implications of a perm (DNA isoforms)now. Planck didn't see the implications of his desperation at the time either.

So, I have use the word 'now' four times now(!)...

...without glorifying the word, the arrow and the time used in the mechanics.

In commemoration to Planck's birthday.

Vincent van der Goes said...

We experience a specific location, whereas the laws of physics do not regard any location special as "here".

And yet this is not considered a paradox. But it's the same thing.

A person experiencing a "now" is an event, not an object. That event has a time coordinate. That time coordinate is the "now" that the person experiences, just like his spatial coordinates are the "where" that he experiences.

Vincent van der Goes said...

To make it more clear what I mean..

There is no definition of "now" in physics because there doesn't exist such a thing as an external or objective "now". It only exists as a component of an experience of a person. And that experience has a time coordinate. Hence, no contradiction.

Memory does not need to be involved to resolve the paradox.

hush said...

It only exists as a component of an experience - ... der it goes

"It" is an "object" and a "event".
Known physical law describes exactly the label "it".

Memory is physical. Learning is physical.

Look at the icon of the clock here - used in Bee's blog about now.

No one will ever have trouble telling you what time it is with this clock and what time is with this clock.

Where the hands of the clock are, is where and what we agreed to -
so what we share with each other makes sense to our senses.

Every now we experience is physically recorded.

Why stop there?
Every interaction a cell has is recorded.

The ships of Theseus are not paradoxes from being carriers of recorded information.

Zaaikort said...

Like everyone else, you are at the centre of the universe, from your perspective.
Everybody is a unique location in space.

But the same goes for 'location' in time: you-now is only one entity of many, the others being you-a-moment-ago, you-two-moments-ago, you-a-moment-later etcetera, in addition to somebodyelse-now, -a-moment-ago, etcetera etcetera.

So: the block spacetime is filled with 4D entities ('events') that are all thinking they are at the centre.


(Oh, I just noticed that Vincent was making the same point. We agree that there is no paradox!)

By the way, this principle is not limited to human consciousness, usually misrepresented as a single entity per person. Any part of your brain or animal brain or even any other bodypart at any time might have its own (limited form of) consciousness, in fact any piece of matter at any time! They are all at the centre of spacetime, from their perspective.

Unknown said...

The flaw in this argument seems to me to be the assumption that we know enough about the Universe to draw an arbitrary generic trajectory "from beginning to end" and assert that it represents an infinitely-divisible sequence of "nows". Particle physics shows us that's false- a particle's "now" only occurs when it interacts with something else. Only events are real- ever heard of "ganzfeld"?

hush said...

The point of the perm is scale.
The molecular scale provides a physical object for all interactions at the molecular scale.

At least one physical object at the molecular scale can be labeled storage. The duration of storage is never considered as long as you assume storage includes time, the arrow, and the 'now'.


Consciousness emerges from the transfer of information 'out' of physical storage.

You can not ascribe consciousness, so define, to lifeless forms of matter because lifeless forms of matter do not transfer the information out of storage the way we have presently assigned life to retrieve physical storage of information.

You want models of life known presently to be consistence with known physical law.

If you ascribe consciousness to all matter you abandon the consistency in mathematics used to describe both states of matter - Life and lifeless.

Of course you can unite both under one model without inconsistency.

Which is the exact same endeavor planned for QG and Relativity too.

L. Edgar Otto said...

Zaaikort,

The conceptual problem is not simply
where or when we are centered in the universe. It is that such an idea of centering that it may be the entire universe and that not distinguishible from the center as multiverse.

For when we replicate from interactive parts a ship of Thesues we can imagine endless independent centers again.
It seems imposing or discovering a structure over the physics and metaphysics is helpful to discern more unity in such modeling.
Fact or fiction we seem to need a sense of the material on which to ground our intuition and understanding. But this sense of the concrete only works if all of our reality is solid and not mostly empty space. We imagine also it works if it is also only ultimately empty space.
Even then we seem to need a concept of substance as we discern phenomenal things such as neutrinos.
Unknown posted a relavant point as to beginnings and endings with reference to substance. Unified gravity would transcend what some say particles as random and absolutely are trying to tell us
where we call natural three fold partion structure quantization which itself may have higher analogs of such centering. The first question Sabine asks of future theory is social rrespondibility in our enterprise of breakthrough inquiry. For now it is the most important in her list of theory's future questions that asks how we may make deeper distinctions and proofs senisibly scientific in its paradoxes of the plausible.

hush said...

Mapping the road to quantum gravity
Physorg - Google title.

Removing infinitely vast amounts of information from both sides of the equation...solves problems.

Makes principles of conservation as far as information is concerned look silly.

L. Edgar Otto said...

hush, good point. Sounds like some philosophic idea of renormanalization.
(I have not searched that article yet).

God can neither be created nor destroyed.
God can be self creating.
We can remove nothing or infinitely small quanties of G from both sides of an equation without changing the total content of information in the Universe which works in mysterious ways. G imagined all present, all knowing, maximally powerful as unity, eternal yet creative, entangled locally or not with bits of finite sentient creatures in the Now or indeffinite future.
G as the great complete model inertial system may be multiplicity or indivisible or some sort of Trinity in between like space or quarks.
Information in a memory or signal may decohere.
As meaning and information are conjugate G may be irreducible as only the factor of meaning.
The hierarchy of analogs as images of mortal and immortal works both ways.

Hawking once thought a complete quantum view of the universe was time as finite if real and infinite if imaginary. This may abstractly be reversed and not necessarily symmetrical over some local region yet over quasifinite contiguous correlations suggest strict but continuous causality over partial models of abstract hidden and fluid phenomena.

A path as a spiral may extend, return, spend time in random choices or be integrated over adjacent roots, groups,and dimensions.

The general point I am making is:
The matrices that involve beginnings and ends, usually as conformal in that they describe physicality foundations, are embedded in the general independent background by which physics would benefit in making clear mathematical and logical distinctions.
Otherwise arguements by design need to do more than rest on save face axioms that like inflation solves nothing of potential singularities or decides as science what is a lack or suspension of belief in reductionism.

Don Foster said...

“…a particle's "now" only occurs when it interacts with something else.”

Our notion of “present moment” is imprecise and of manifold natures. Surely though, it is implicit in physics in any act of measurement, anytime a discrete value is recorded for a physical metric. It is an observable, an event; it is our current news about the greater universe received at the tip of our antenna. It is action on an interface, a boundary transition mediated between energy and information. And it is energy, with its astoundingly precise conservation, that threads these events together.

I don’t know if the mathematics of the block universe has terms conveying the notions of currents or of boundaries, but I sense that we will have a better understanding if we see that implicit in any “interaction” is the news that the universe is of at least two parts. Further, that we can show that all boundary instances derive from one greater boundary between two parts of an ultimate whole.

Best.

hush said...

hush, good point. Sounds like some philosophic idea of renormanalization. - Edgar

There must be people where renormalization is like a second nature to them - like the patches for glitches programmers are call on to eliminate.

Surely they will tell me what I am missing in life - fun or frustration.

Don Foster said...

Given a choice, I would not live in a block universe. I think it would feel like being one of those ghost characters in the movies, able to witness but not really touch, knowing the consequence of any present moment had long ago been immutably determined.

Still, there is some consensus that the block universe is our objective reality. Or rather, that it is an elegant mathematical construct with deep implications for our objective physical reality. If it is true, then there is another equally valid truth.

"What we see is not Nature,
But Nature exposed to our method of questioning"
-- W. C. Heisenberg

The word “science” derives from the Proto Indo/European word meaning, “to cut, to divide.” And one thing we learn from conic sections is that what you get depends on how you slice it. All the significant trajectories that arise from the intersection of two simple geometries, a cone and a plane, depend on the “how” of that intersection.

And consider the intersection of more complex geometries; say the horizontal plane of a water table and that of a folded bit of earthly terrain. That intersection may trace out the perimeter of a mountain lake, a perimeter whose actual length is indeterminate, may only be approximated.

So, is the block universe simply the intersection of a mathematical formalism with the very complex geometry of the living universe? Is it some ultimate objective truth about the nature of the universe, or simply one revealing slice, along a certain axis?

"What we see is not Nature,
But Nature exposed to our method of questioning"
-- W. C. Heisenberg

"The prudent mariner will not rely solely on any
single aid to navigation."
-- Coastal chart legend, U.S. Coast Guard –

What is the actual utility of the notion of a block universe to a Prudent Mariner with her own complex geometry and particular angle of inclination?

Because there she is, a bit of clay twisted off from the common substrate. The umbilicus is cut and she stands seemingly apart, a bounded region with a complex internal geometry containing more than 10^15 aids to navigation. And suddenly she is proceeding step-wise, tracing out a very particular path over intricately woven terrain.

She is her own scientist. She learns the ways of tides and currents; maps and remembers the hazards, can increasingly anticipate outcomes and navigate to some point far across the horizon, arriving at the appointed time.

The point is, why is her reality necessarily subordinate to some “objective” reality. What is reality after all, if it is not well, real? It is not simply notional. It is urgent in a present moment with its rain and thunder and wind lifting off rooftops.

Is there a physics that can accommodate her reality as real?

"The truth will set you free.
But not until it is finished with you."
- David Foster Wallace

Best.

hush said...

The word 'but' is special.
What follows after this word is always a contradiction to what come before.

English makes no exceptions here.
What is a language extension that makes no exceptions?

hush said...

come=came
Typo correction.
See above comment.

Prose is prose is prose.
Very pretty and fun to read, Don.

Svik Vik said...

A lot of comment about nothing.

David Whitmore said...

m'Lady;
How is Time measured?
I'm not asking whether it is a matter of objectivity or subjectivity, or even a matter of locality.
Is Time simply a collection of discreet instances, one after another? Or is it a continuous flow, much like a waterfall?
I've gotten multiple answers from my professors; basically, the answers I get amount to "Yes". And I received a 'Both' answer from one of my Physics Professors.
Admittedly, this was back in the mid-80s; so I am curious as to whether this has been more accurately determined.
I thank you for reading this, and for any answer you may have for me. Have a great day.

hush said...

For known life forms time is discreet at the molecular scale.

No physicist will deny the incontrovertible evidence for discreetness at the atomic scale.
That was the scale that delivered the clincher in favor of Nature's discreetness in the first place.

Neurons' DNA segments undergo damage (double strand breaks)from memorization and learning. The inputs are the senses. The immediate forthcoming repair is the storage. Why? Because the repaired and original segments differ. How? From segmental DNA strand inversions. The DNA sequence is unaltered yet the repair (identical replacement segments)now give rise to gene expressions differing from the expressions the original DNA strands expressed.

The order in which damage and subsequent repair occurs is the order which humans have now(!) come to label "time" - philosophically as well as scientifically.

There is no "erasure" of any of all neurons' repaired DNA.
(You can brute force remove neurons physically which is synonymous with "erasure", "loss", "destruction" or "annihilation")

"Loss" of memory is simply more damage&repair to undamaged neurons who expressions now favor signal pathways to themselves and discourage travel "withering through non-use" from pathways to previous damage and repaired DNA neurons strands.

Electroshock is uncontrolled damage and repair. Too bad.
Continues to this day.

I am boring you. You wanted more physics and less neuroscience.

I did not make any of this up.
The rest of neuroscience is imagined. All this mystical chatter about the mind and brain.

You are damaged. We all are.
Now repaired. And much better off than time, the arrow, and now.

hush said...

Dear Busy as a Bee,

A Blog search on this blog for Quantum Zeno effect returns no results.

Are you willing to waste two words on the subject?

Bee:
No way!

Just kidding, Bee. All in jest.
All the best.