{"id":252,"date":"2025-03-07T17:10:30","date_gmt":"2025-03-07T17:10:30","guid":{"rendered":"https:\/\/experimentalfrontiers.peachpuff-wolverine-566518.hostingersite.com\/?p=252"},"modified":"2025-03-07T17:12:28","modified_gmt":"2025-03-07T17:12:28","slug":"physical-time-and-time-as-we-experience-it","status":"publish","type":"post","link":"https:\/\/scienceblog.com\/experimentalfrontiers\/2025\/03\/07\/physical-time-and-time-as-we-experience-it\/","title":{"rendered":"Physical time and Time as we experience it"},"content":{"rendered":"

A CLEFT BETWEEN the future and the past
\nthe breath between tomorrow and today
\nthe lonely isle or sandy, sea-locked cay
\nsurrounded, compassed by the ocean vast
\nupon whose shore my soul is stranded, cast,
\nmarooned and shipwrecked, spirit washed away
\nthat bounded by horizon of the day
\nuntil I spied the telltale sail at last
\na phrase\u2019 turn that awaits its crowning rhyme
\ncausality is intimate relating
\nthe watches-of-the-night-denoting chime
\nto signal that the darkness is abating
\nfor all good things will come to me in time
\nand I can make the flowers grow by waiting<\/p>\n

\u2014 Max Leyf<\/p><\/blockquote>\n

The way physicists think about time includes built-in contradictions. No one denies this, and there is an extensive literature in the philosophy of physics, with little agreement.<\/p>\n

The paradox most commonly addressed is that the thermodynamic \u201carrow of time\u201d is nowhere to be found in the fundamental equations of physics. Thermodynamics is supposed to be a derived science, based on the microscopic equations of physics, which are fundamental. But the fundamental equations are exactly the same going forward or backward in time, while the derived equations (about increasing entropy) tell of irreversible change happening in one time direction.<\/p>\n

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Thanks for reading Unauthorized Science! Subscribe for free to receive new post.<\/p>\n<\/div>\n<\/div>\n<\/div>\n

We experience past and future as different. We have a sense of agency about the future, while we regard the past as set in stone. Where does the asymmetry come from? If the equations of particle physics are indeed the root of all reality, why, in our experience, is the forward direction of time so different from the backward direction?<\/p>\n

But there is a bigger paradox, addressed only obliquely, if at all, by physicists. The most salient feature of our experience of time is that there is a \u201cnow\u201d, distinguished from all other times. Essential to our conscious experience is a sense of moving through time. But this \u201cnow\u201d is nowhere to be found, in all the equations and laws of physics.<\/p>\n

\u201cThe Moving Finger writes; and, having writ,
\nMoves on: nor all thy Piety nor Wit
\nShall lure it back to cancel half a Line,
\nNor all thy Tears wash out a Word of it.\u201d
\n\u2015\u00a0Omar Khayy\u00e1m<\/strong>\u00a0(tr Edward Fitzgerald)<\/p><\/blockquote>\n

You could pore through all the equations of physics \u2014 equations that work so well to describe everything from particles in a high-energy collider to the motion of galaxies \u2014 all these equations contain no idea of a special \u201cpresent moment\u201d. Our subjective experience of time as something that moves has no place in Newton\u2019s equations that govern motion, and this remains true in quantum physics.<\/p>\n

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The sense of a moving \u201cnow\u201d is so essential a feature of our experience that it is inseparable. Conscious awareness and the \u201cflow of time\u201d are parts of one concept, or different ways of speaking about the same thing.<\/p>\n

It gets worse. Our conviction that \u201cnow\u201d is special is powerfully reinforced by the fact that everyone we know experiences the same \u201cnow\u201d that we do. For people who are close enough to interact with us, their \u201cnow\u201d is the same as ours to within a millionth of a second, which is a time too short for our perceptual apparatus to distinguish. Communication at the speed of light connects any human to any other within a few hundredths of a second, which is right at the threshold of a time interval that our senses might perceive. In everyday conversations, time lags from the speed of sound are similarly in the range of hundredths of a second.<\/p>\n

Absolute, true, and mathematical time, of itself, and from its own nature, flows equably without relation to anything external, and by another name is called duration: relative, apparent, and common time, is some sensible and external (whether accurate or unequable) measure of duration. \u2014 Isaac Newton<\/p><\/blockquote>\n

Our subjective experience is of a moving \u201cnow\u201d. Einstein showed us that the subjectivity of time is relative, and he went further to opine that \u201cnow\u201d is an artifact of our human condition, an illusion without physical significance. More recently,\u00a0Julian Barbour<\/a>\u00a0has written articles and an entire book denying that time has any reality. This, in my view, is an extreme perversion of science. The purpose of science is to explain our experience, to make it comprehensible and (somewhat) predictable. When science tells us that there are no explanations to be had because our experience is an illusion, science is gaslighting us.<\/p>\n

It\u2019s tough to make predictions, especially about the future.
\n\u2014 Yogi Berra<\/p><\/blockquote>\n

It remains true in quantum mechanics that the equations themselves are symmetric with respect to forward and backward time; and yet, in practice, we always use the equations of quantum mechanics to predict the future from the past, never to \u201cretrodict\u201d the past from the future. This could be regarded as an extra, unstated rule in the foundations of quantum physics: The wave function must be used to predict probabilities of the future, but never of the past. This suggests a way in which quantum mechanics might offer a basis for a subjective \u201cnow\u201d.<\/p>\n

\u201cNothing ever happened in the past; it happened in the Now. Nothing will ever happen in the future; it will happen in the Now.\u201d \u2014 Eckhart Tolle<\/p><\/blockquote>\n

Quantum mechanics famously requires \u201cobservers\u201d to complete the theory. For each observer, observation happens in the subjective \u201cnow\u201d. The choice of observation is akin to our feeling that we are free to direct our attention as we wish. It is by this choice that consciousness enters the physical world, and by which we assert our influence on the future.<\/p>\n

Is there a relationship between quantum measurement and life that gives direction to physical time?<\/h2>\n
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A thought I’ve entertained of late is to identify what we call “consciousness” with the sense of a moving “now”. Observation is the means by which consciousness enters the schema of quantum physics. The Schr\u00f6dinger equation tells how probabilities evolve between observations, but the human (or animal or plant) choice of what to observe shares with the equations a causal role in bringing the past forward to create a future.<\/p>\n

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Dali<\/figcaption><\/figure>\n
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We (and all of life) participate in creation by our presence as witness. In choosing the focus of our attention, we are participating in creating the future each moment. This is the physical significance of the “now”.<\/p>\n

There is a quantum phenomenon called the\u00a0Inverse Zeno Effect<\/a>\u00a0by which repeatedly choosing what to measure can influence a quantum state to morph into a different state.<\/p>\n

I suggest that the incorporation of consciousness into the foundations of physics invests time with its physical character \u2014 including causality and the increase in entropy \u2014 that separates one-way macroscopic physics from the time-symmetric equations of fundamental physics.<\/p>\n

If this seems too distant for you to hang on to\u2026<\/h2>\n

Background \u2014 if this is starting to make your head spin, I suggest reviewing\u00a0what I have written about the quantum measurement problem<\/a>\u00a0in the past. More\u00a0here<\/a>\u00a0and\u00a0here<\/a>.<\/p><\/blockquote>\n

If you\u2019re at all interested in the conceptual replacement of a physical universe with a\u00a0living universe<\/a>\u00a0at the foundations of science, I recommend reading the background. This is the subject of a\u00a0book that I hope to complete this year<\/a>, and I will be publishing excerpts on this ScienceBlog as I write them.<\/p>\n

For those who are impatient, here is a much-too-condensed summary of a revolutionary reconception of the foundations of science.<\/p>\n