A Time Machine:John Archibald Wheeler, and Delayed Choice

How is it possible to change an event after the event happens? At the quantum level, that is what can occur. Time is not linear but somehow jumbled. (Does this have philosophic implications for the study of free will? That is, events can be changed at the micro level.)

If you aren't confused by quantum physics, you really haven't understood it. (Neils Bohr)

In a sense, time machines already exist. In quantum theory, actions in the present could change the past, or at least determine it.

To explain very puzzling quantum phenomena Neils Bohr and Werner Heisenberg provided our world with the 1927 Copenhagen Interpretation of the double slit experiment (see Schrödinger's Cat, 2 January 2004). The Interpretation still stands.

When passed through two slits, a particle behaves strangely indeed. It presents an interference pattern, which can only be accomplished by a wave. The particle has become a wave, and is no longer a particle. To understand how this could possibly happen, physicists sought to record and measure a particle as it passed through a slit. But the very act of observation causes the particle to no longer behave as a wave. This is termed wave function collapse. How can this be? How can it change into one thing, then change again, simply because it is being measured and recorded? Recall Neils Bohr, above.

The interpretation regards as meaningless questions like, Where was the particle before I measured its position? Measurement itself causes wave function collapse.

How is it possible that observation/measurement somehow alters that which is observed/measured? It's cartoonish. Imagine Bugs Bunny firing bullets, which become a spray of water, splitting in order to go through two holes at once to reach the target. Imagine Bugs with a water hose that becomes a pistol again. Some aspects of the world at the quantum level are out of Looney Tunes.

In considering the relationship of observer to experiment, John Archibald Wheeler concluded that choice by an observer may determine experiment outcome. And this, regardless of when the choice is made, even after the "bullet" (particle) is fired. On our "common sense" level this is akin to saying that experimenter choice will determine what a bullet will do after it leaves a gun muzzle.

This is partly how it works:

Fire a photon toward a screen with double slits.

The photon passes through one slit, the other, or both. Presumably whatever the photon does, it does so while passing through the slits.

Past the slits, it heads toward a back wall.

At the back wall, the experimenter has two separate photon detection choices. One is leaving in place a screen while the photon is in transit to the back wall. The other is removing the screen.

After the photon is shooting to the back wall, choice is made to remove the screen or not. This is the delayed choice.

The experiment is much more detailed but the paradox is this. The delayed choice determines whether the particle passes through one slit, the other, or both. The delayed choice of how to measure the particle determines how the particle behaved at an earlier time. A choice in the present seems to have changed the past.

The quantum level experiment has yielded results largely as Wheeler expected them.

Déjà Vu and Physicist Julian Barbour

Déjà Vu and Physicist Julian Barbour

An old woman sits in her wheel chair in a nursing home, a photo album on her lap. She shows another old lady pictures of herself with her first beau on the village green, of herself in bridal gown, of her child sitting on her knee. She looks up at the bare walls, and sees somewhere herself at sixteen, turning many heads, her father carefully screening suitors at the door. It all happened so fast, first that and now this. She opens the album to a new page to show her husband in the year before he died, proudly washing their new Ford in the driveway.

Consume my heart away, sick with desire and fastened to a dying animal. (W.B. Yeats)

In Julian Barbour's world, every first date, every kiss, every senior prom, every marriage, every departing is repeated precisely and endlessly. Every hot dog at a baseball game will be eaten again and again. A teenager's coolness lasts forever. Couples meet and fall in love for the first time and their love never dies. They grow old together or become divorced. Or one watches the other become sick and waste into death. Gew gaws hanging from their crib, as infants they awaken to the bright world and it starts over. Sometimes during the night as middle aged men and women, they dimly recollect something, but life presses them forward and they forget.

It has all happened millions of times before, Earth, the cosmos, hot dogs, the World Series, Caesar's conquests, everything. Nothing changes. Time and motion are illusions, according to Julian Barbour.

Before dismissing Barbour, consider that common sense doesn't tell you that without Earth gravity you would hurtle off into space. It doesn't tell you that passing through your body each second are 400 trillion neutrinos, some left over from the Big Bang that created the universe.

Barbour understands the outrageousness of his ideas and has trouble accepting them himself. Still, reason has led him to his view. He believes that most theoretical physicists have ignored time.

His credentials are solid, and prominent physicists take him and his unconventional ideas seriously.

He lives in South Newington, twenty miles north of Oxford, and not far from the fields where little Alice Liddell played, the child who inspired Lewis Carroll's Alice in Wonderland. She will forever play there if Barbour is right. Today other children frolic in the fields.

The central problem in modern science is the disjuncture between the gravitational world, where we live, and the quantum mechanical world, with tiny particles. Barbour contends that the problem arises because physicists mistakenly take time as real for their purposes.

Time differs, depending on the level of observation. At the quantum level it ticks away as it does in our lives. At the larger level of relativity things aren't that easy. Einstein bent the universe into spacetime, a seamless fabric. Space and time curve around stars and planets, causing light to bend rather than travel straight. Time slows down or stops near black holes.

Barbour arrived at his proposal through an equation developed by Bryce DeWitt and John A. Wheeler which tried to join the two worlds, quantum mechanics and Einsteinian general relativity. Imagine a grain of sand, then imagine all the beaches on ours and other planets. The grain is the quantum world; the beaches, the gravitational. DeWitt and Wheeler used Schrödinger's equation as the basis for calculations. (Irwin Schrödinger of Schrödinger's Cat fame)

Because their approach allows that energy changes with time, which doesn't happen in the universe at large, Barbour eliminated time. Unlike atomic interaction, the universe has nothing to interact with except itself. Get rid of time, and the Wheeler-DeWitt equation becomes a means to merge quantum and cosmic realities.

The crux of Barbour's argument is that each, past, present, and future, exists separately everywhere and John A. Wheeler. Our universe isn't single nor does it pass through time. He calls the now the universe completely frozen like a snapshot. If in an instant we could look at our hemoglobins, we would see one hundred million million of these hemomolecules change, which means that every split second we are a different person. Or, think of a movie film. Each frame captures one possible now. Nothing moves within the frame but the reel gives the illusion of motion.

We are everywhere at once, inhabiting a huge, static, everlasting tableaux that includes the entire universe at any given moment. Call the tableaux Now Forever.

As he develops his position, perhaps Barbour would lead the illusioned people of Plato's cave into the light of reality. Each now never changes, is timeless. Each life, so to say, is still. Barbour calls this world of still lives, Platonia, after Plato, who argued that reality is composed of eternal and changeless forms. The shadows in Plato's analogy compose the illusory flux of time.

Barbour says only a madman would deny we don't change much from second to second, but still asks in what sense can we be said to move. Nothing really moves, he contends. Each of our separate nows contains information about our senses of identify, memories, hopes, and fears. They are like snapshots. We are part of the snapshots.

We are immortal. Of that Julian Barbour is convinced, although he acknowledges that we should still buy life insurance. His immortality implies that life exists alongside death, that we do not pass through time.

I am not sure how this would console the old woman in the nursing home. Her loneliness is palpable, her yearnings real. Yes, she would experience her youth and happiness again, but so, too, would the photo album reappear on her lap as she sits, gray, wrinkled, in the home.

While Barbour would bridge the disjuncture between the quantum and gravitational worlds, we must live with the transit of what we call time. The old woman again opens the photo album, looks at herself as a young girl, skirt spread daintily on the village green. Her swain, she recalls, had taken the photo. Oh yes, what was his name? So handsome, so full of fun. At nineteen, he was killed in action at the Somme. What if she had married him? She closes the book as she hears the nurse with meal tray entering the hall to her room.

Like Julian Barbour, T.S. Eliot reveals profound fascination with time. Eliot wrote these lines for her, for all of us, in Burnt Norton:

Footfalls echo in the memory
Down the passage which we did not take
Towards the door we never opened

Notes on Time and Choice: Daniel Dennett, Benjamin Libet, Roger Penrose, John Wheeler, and Advaita

Notes on Time and Choice: Daniel Dennett, Benjamin Libet, Roger Penrose, John Wheeler, and Advaita

Everything humanity thinks and believes about itself is predicated upon two concepts. One is free will; the other is self. Look wherever you will, whatever society you find, and all cultures contain a belief in some kind of will, and self. Civilizations, economies, legal systems, art, religion, all arise from them. But what if they are illusory? Pedro Calderón de la Barca (1600-1681) said that life is a dream. Nobody wants to believe that; such belief seems to threaten entire human edifices, our history and struggle to arrive at these Twenty First Century shores.

Still, both concepts are based more on belief than on indisputable evidence. They are similar to St. Augustine's description of time, of which he said, " When you don't ask, I know; when you ask, I know not." Look within, show me your self. No, not that. That is only a name, an occupation, a physical description, a life history, or a relationship to others. Your self. Where is it? You see my point.

Declarations about choice are time-bound, whether they be fatalist, determinist, or free volitional.

Calm, sustained introspection reveals that "choice" arises after the fact. This occurs for jnanis, enlightened Hindu masters, as taught by advaita. Benjamin Libet's experiments also demonstrate as much. An event, either thought or muscle response, precedes volitional sense. The analytical approach of advaita espouses that through such introspection freedom eventually occurs. The self disappears, seen for an illusion, a shackle. Nobody chooses because nobody exists to choose. Does choice get done? Ramana Maharshi, a revered modern master, dismissed the question with this remark: "There is neither freedom nor destiny. This is the final truth." He meant that any analysis, any attempt to explain, plunges the sage back into objects of consciousness, things perceived, when actually only the Perceiver is.

The realization is liberating, but is the explanation deceptive?

Daniel Dennett would argue that it is deceptive. Essentially, he says that we must develop a new paradigm about volition. Our ways of thinking are faulty. In his book Freedom Evolves, he considers free will as morally important, and of course, he is right. Our entire legal system is predicated upon the belief that people can avoid wrong doing. He holds that free will does exist but not in the way people normally think about it. This may seem contradictory because he also says that conscious will is an illusion. He means that it does not exist in the traditional sense. We have no conscious voluntary volition. Nothing we choose is decided upon consciously. Yet, we remain morally responsible. How is this possible? How can we be morally responsible if free will is not conscious?

Dennett would say, Not so fast. The problem here is with words. We accept that an atom can be split, although we cannot sense it as an event. Still, the concept serves thinking about quantum events. We cannot experience free will, but we can gain understanding if we accept that words have limits and we think about them in new ways. They can yield different meanings. Like many current thinkers and researchers, he acknowledges that the old view of free will is gone forever, but he asserts that another kind is available. We can still value free will. In order to survive, we can value life with an artificial heart rather than one that no longer pumps. What is this new heart, this new free will?

Today, discussion of volition must account for Benjamin Libet's pioneering experiments. (This brief article cannot do them justice, but they are explained elsewhere in this blog.) To discuss free will, a key element of Benjamin Libet's experiments must first be explained.* Subjects were told by Libet to flick their wrists whenever they chose to do so. When Libet's subjects indicated they had "chosen," they revealed a 300 millisecond lapse between the unconscious behavior trigger and the brain's sense of a "decision." This gap is termed the moral void, a time indicating the lag between the actual trigger and the awareness of choice. The conscious sense provided the illusion of control, of decision-making, but the "decision" had already been made. *(For a fuller explanation, see the references to Libet at the bottom of this article.)

Since they were first conducted in the early 1980s, Benjamin Libet's experiments have had researchers and thinkers debating the issue of free will, as on the face of it the experiments suggest that the sense of decision occurs after the action, not before it.

Dennett is one of the thinkers in the debates, and to explain his view of free will, he takes Libet's experiments as his starting point. The problem, he says, has to do with understanding of the self. We must develop new understandings for the word, self. Dennett illustrates self in relation to these locations in the brain: in the rear, at the vision center; in the middle at the classic Cartesian theater; in front at practical reasoning. He then offers three scenarios.

The sense of self sits in practical reasoning, awaiting the contents from the vision center. Perhaps visual content is late by the time it arrives. The self thus gets dated information.

The sense of self sits in the vision center, and also experiences, say, a 300 millisecond time delay.

The sense of self sits at the classic command headquarters, in the Cartesian theater, where all supposedly comes together and consciousness happens. Contents arrive at the same time, but one message, the decision to flick the wrist, left 300 milliseconds ago, while another, the readiness potential, or planning stage, left 550 milliseconds ago. Even though they happened differently, they are sensed as happening simultaneously.

Dennett observes that each of these scenarios prescribes a locus for the self, but what if the self doesn't preside in a single place? One explanation he offers is that the self could have been at practical reasoning, the vision center, and the command headquarters--at all of them. The self simply misjudged the clock when reporting the moment of decision. Why? Because the self had to return to command HQ to pick up the new information, and by that time the clock hand had moved past the point of actual decision. This is one explanation. He offers various hypotheses, but his essential point is that the self must be distributed by space and time within the brain.

The self, he maintains, is not a point within the neural loop, but is the loop. That is how it exists within space. But it must also be spread in time. It cannot be measured in instants. Dennett construes the self as a decisional entity presiding over longer durations.

Dennett debunks Descartes' self, the self of I think, therefore I am fame. For Dennett, we do not exist as a self, a little man or woman, inside the mind who pulls levers and pushes switches in the conduct of our daily affairs. Most of what we do is unconscious and automated. That is why he says the old view of free will is dead. He instead argues that we should not discard volition, but should see it in a new light, as he tries to explain. His new free will is neither centralized nor immediate in its volition. In this, he is similar to Francisco Varela's Emergent Self. * ( See Dennett in Shakey, Beavers, and Cartesian Theater, and Cartesian Anxiety: Francisco Varela: The Emergent Self and Its Implications for Eastern No-self.)

Think about sports in this regard. Nobody has time to make decisions. Inside a tennis player, nobody pulls levers, nor pushes any buttons. The player does not decide how to return a serve. He acts as a result of pre-conditioning. His intention is prepared by mind-set and a plan to defeat the opponent. Attention always allows response faster than any effort at decision. With attention, intention can advantageously occur. Without attention, the best of intentions may go astray.

My comments on Dennett: He has tricked self out in new clothes, but he offers a different concept, not any pioneering new theory, or further evidence. Nothing is new here--just the usual clever, ingenious Dennett. Although I don't buy his concept, I also understand his concern for the sense of moral responsibility. He regards people as self-monitoring, which provides a feedback loop for future behavior.

Somewhere in his discussions, he speaks of Dumbo The Flying Elephant, who cannot fly until crows give Dumbo a "magic" feather. Holding the feather in his trunk, the little elephant believes that he can and with it he does fly. In Dennett's book, Freedom Evolves, the author offers our feedback loops a new feather, a different understanding of self. Still, it remains a feather. Would Dennett deny the fact? I don't think so, but he would insist that people are enabled by understanding its function and believing in its potential. Feedback loops reinforce belief systems. He realizes that belief systems have powerful effects. They condition both individuals and entire societies. For a discussion of this, see My comments, in the article The Illusion of Free Will: Physicist Amit Goswami, Sage Ramesh Balsekar, and Neuroscientist Benjamin Libet.

Dennett premises his argument on cause and effect and this assumption is time-bound. From the point of view of advaita, however, cause and effect, time itself, may be regarded as illusory. (This is indeed how advaita holds causality in its other teachings, many of which derive not from dogma but from empirical introspection.)

Quantum consciousness. Does the issue of self and choice involve a form of wave function collapse in which a state becomes determinate in accordance with the observer? * That is, does the reported time sequence (choice after the fact) fall into place only when observed? (This would explain why advaita posits non-causality on the one hand and causality on the other. One is apprehended in "higher" consciousness while the other is seen in a normal state.) * (See Schrödinger's Cat.)

Of Roger Penrose, Bernard Baars says that " The really daring idea in contemporary science is that consciousness may be understandable without miracles, just as Darwin's revolutionary idea was that biological variation could be understood as a purely natural phenomenon. We are beginning to see human conscious experience as a major biological adaptation, with multiple functions. It seems as if a conscious event becomes available throughout the brain to the neural mechanisms of memory, skill control, decision-makings, anomaly detection, and the like, allowing us to match our experiences with related memories, use them as a cue for skilled actions or decisions, and detect anomalies in them. By comparison, unconscious events seem to be relatively isolated. Thus consciousness is not just any kind of knowledge: It is knowledge that is widely distributed, that triggers off widespread unconscious processing, has multiple integrative and coordinating functions, aids in decision-making, problem-solving and action control, and provides information to a self-system." (Bernard J. Baars, "Can Physics Provide a Theory of Consciousness?: A Review of Shadows of the Mind by Roger Penrose," in Psyche: An Interdisciplinary Journal of Research of Consciousness, May 1995)

Baars refers to Penrose's efforts to find a consciousness counterpart to wave function collapse in physics, the central modern mystery, and the one that has caused "new-agers" to invoke Eastern mysticism as an explanation, although in some ways apples are being compared to oranges.

The problem lies with observations that cause wave function collapse. The observation itself seems to cause the collapse. By the act of perceiving, the observer changes that which is observed. In double slit experiments, somehow waves become particles in specific places, despite abstract probability that they should be distributed across a target. Physicist and mathematician Roger Penrose has argued that wave-function collapse within brain microtubules alters consciousness so that we observe events at the quantum level that we can't explain. Microtubules are tiny enough to fit at the quantum level while neurons belong at the level of classical physics. Within neurons, cytoskeletons form the structures that are the "glue" for cells. Inside them are microtubules, only 25 nanometers in diameter, which control synapse function. This suggests that our time-bound perception distorts whatever the case might be.

The brain does not seem to be wholly alienated from quanta. Evidence indicates that it is capable of consciousness at the quantum level. Adjusted to darkness, an eye can detect a photon. These single photons, though, do not involve wave function collapse.

The full article can be found at Borderland: The Last Frontier of Science, 23 January 2004.

For quantum observations, John A. Wheeler proposed a delayed choice experiment with profound implications. Assume a galaxy many light years away with light emitted billions of years ago. In brief, it implies that as we observe the light we alter its path. The paradox is that our observation changes the path of light that billions of years ago had already reached the point of our observation. How can the light have been emitted before observation, if the observer can alter what happened before it was observed? At the quantum level, the experiment has yielded results largely as Wheeler expected them.

A detailed article is at John Archibald Wheeler, Delayed Choice, and Time.

We are indeed time-bound, and time appears to be necessary for the way we apprehend "reality." All theories of volition include time, cause and effect, in their explanations as this is how the classical world is experienced. But is it a final truth to say one thing follows another? Or is it descriptive of a perception mechanism? (See Peter Lynds and time.) Julian Barbour: "Most physicists have a deeply rooted notion of causality: explanations for the present must be sought in the past. . . This instinctive approach will be flawed if the very concept of the past is suspect." (The End of Time: The Next Revolution in Physics) For more of Barbour on time, see Déjà Vu and Physicist Julian Barbour.

For Articles on Libet see Benjamin Libet and Free Won't and  Balsekar, Goswami, Libet as well as Looking For Self: Yogi Berra, Forks in The Road, and Free Will.

Dennett can be found at Shakey, Beaver, and Cartesian Theater, as well as  Daniel Dennett and Choice Machines, and Compatibilism.

Home______Julian Barbour & The End of Time

Here is an excerpt from the Science & Spirit interview with Julian Barbour. A link to the magazine is at the bottom.

Is time an illusion, a piece of quantum trickery that fools us into a false sensation of flow in the midst of a static reality?

Julian Barbour is an independent theoretical physicist, who lives and works just outside Oxford, England. In his ground-breaking new book, The End of Time, Barbour argues that while the laws of physics create the powerful illusion that the flow of time is real, there is increasingly strong evidence that the universe is in fact timeless. Barbour draws on quantum theory to show how the structures of the universe may in fact be static, while giving rise to the appearance of the flow of time, and he brings together quantum mechanics with the theory of relativity in a bid to solve one of the greatest paradoxes of contemporary science: the gap between classical and modern physics. . . .

Science & Spirit: We all have a strong everyday experience of time. How is that experience problematic from the perspective of theoretical physics?

Barbour: I think that our psychological experience of time--our very powerful sense that it flows, and our ability to make clocks and keep appointments and so on--may be distorting our view of the world. The human brain may be the most complicated, intricately ordered part of the universe that there is. And it's particularly slanted towards temporal aspects of things. I think we are projecting our psychological experience out into the external world when it probably isn't there. I think the evidence that there isn't a time out there in the way that we feel it inside ourselves is strong. I always quote the great sentence of Copernicus: "We should be careful not to attribute to the heavens what is really in the observer." . . .

S&S: What about the actual experience of time, as opposed to the mental models we make of the universe?

Barbour: . . . I recently heard of a Frenchman who was shut up in a cave for five days. . . . . And after five days, he was counting two and a half times too slowly. All his other bodily functions were functioning at the same rate, so the conclusion the experimenters drew from this was that our sense of the passage of time is not directly linked to our other bodily functions. . . .

S&S: Do you think the seasons, like the body, are there as natural clocks, regardless of our psychological relationship to them?

Barbour: I am a realist, and certainly the seasons are real as far as I am concerned. . . . I actually see timekeeping as no more than accurate grid locations in Platonia. When we said we would meet at six o'clock, I see that as a place in Platonia. A watch is a kind of compass to direct us to the right place.

S&S: What is Platonia?

Barbour: Platonia is the land of Nows--and a Now is a frozen moment. Imagine freezing the whole universe, taking a snapshot of it: not just you and me sitting here, but the whole of Oxford, all the way out to the most distant galaxy in one instant, that would be my idea of a Now. And then consider the collection of all possible, conceivable such Nows: every one that would be possible with the makeup of the universe. The totality of such Nows is the land I call Platonia. (More at Science & Spirit. The link is current as of this blog article date.)

In this blog also see the article, Déjà Vu & Physicist Julian Barbour, 13 January 2004

Home_____Brain in A Vat, Time, and Peter Lynds, College Drop Out

Brain in a vat. Assume that a brain could live in a vat of chemicals and, wired by external electrodes, it would have all the normal experiences: childhood, sex, falling in love, parenting, even skiing, or sky diving. It imagines itself a person capable of a full range of activity. It has beliefs: it is a person with a name, say, Harvey Smedlap; it has a family; it enjoys food; it has orgasms; a god created it and protects it. It regards all this evidence as reliable.

Now, a question: how can one differentiate his own beliefs from that of the brain in the vat? How can one say that his evidence is more reliable than that of the brain?

Peter Lynds. Another, this one antique: How do you reach a goal? You cover half the distance, then half of that, then half of it. You keep halving your distance but always another half remains.

In fact, we do reach goals, but the above paradox has stumped philosophers for centuries. (Newton was able to predict the goal, but his calculations were inferred from a universe quantum physics undermines.) A 28 year old New Zealander and college drop out thinks he has an answer, and he has many physicists impressed with the boldness of his theory.

Tutor at a broadcasting school, Peter Lynds believes that his idea is quite simple and should have been recognized by other thinkers much earlier. Of course, he has uncommon sense. The problem has been with common sense, which gets in the way of understanding and has done so for centuries.

Peter Lynds believes that the mistake lies with thinking of time as a series of moments. From antiquity to the present, philosophers and physicists have assumed that objects in motion have determined positions at any instant in time. It's not true, Lynds says. In an interview with Astroseti.org, he says "People have wrongly assumed that an object in motion has a determined position at any instant in time, thus rendering the body's motion static at that instant and enabling the impossible situation of the paradoxes to be derived." One can infer from this that we believe in time because our brains are hard-wired for us to do so. Neurobiology.

Of course, the implication of his idea is that time has no flow as it would require progression through definite instants. If no progression, and no flow, then there is "freeze." We don't move, you and I. We are frozen in time.

This, too, seems paradoxical but reason offers at least one way out. There is no you or I, at least not in the usual, the common, sense. This requires exploration of one's own mind, as philosopher David Hume did, wherein he found no sufficient empirical evidence for the existence of a self. Of course, he was preceded in this by millennia of consciousness explorers from the Buddha and before.

In brief, can Lynds' theory make sense? Yes, but uncommon sense is required. After all, among the adults, a little boy pointed out that the emperor was naked.

The paradox is enhanced by the evidence of physics. Time does not seem to be inherent in nature, which, so to speak, has no need for it. Einstein's Special and General Theories have demonstrated that

a present moment, or "now," does not underlie physical processes.

judgments of simultaneity depend on position. Recall the relativity thought experiment in which (inside a train) a thrown ball reaches its target sooner for an outside observer than for a passenger on the train.

the mathematics of relativity suggests a block universe in which events don't occur but, rather, are mapped out in space-time so that nothing "happens" because all is rather like "here": one person's "here" (read: "now") may be a cafe on the Left Bank in Paris; another's might be an espresso house in North Beach, San Francisco. The "here"/"now" is "location" rather than "event." Events haven't happened in the "past"; don't happen in the "present"; nor will happen in the "future."

Albert Einstein: "There exists, therefore, for the individual, an I-time, or subjective time. This in itself is not measurable." Time as flow, as progress, is a product of our perceptions, our neurobiology, and has no basis in nature.

All of this is counter-intuitive. It defies common sense.

In its early days, physics wanted to separate the psychological from the evidentuary or traditionally theoretical. It finally accepts that these aspects are hopelessly intertwined. This takes me back to common vis a vis uncommon sense. All calculations, all theories, all experiments ensue from ways of seeing. If the emperor seems clothed, then he will be described thus. What do I mean? Henri Bergson said that time is merely a personal construct (read: psychological) that we force as fact.

I might as well end, then, on the psychological. Marcel Proust exquisitely explored his own psychology, to include how tea tasted in his childhood. I will close with part of a lovely passage, one that opens Swann's Way, of In Search of Lost Time (or Remembrance of Things Past, as I learned it):

"And as I would lay in bed, I would listen to the whistle of trains. At which point I would try to reckon the passage of time."