Time (Some rambling thoughts)

 Time

2024-12-08 to 11 

Einstein’s Special Relativity (SR) says that time is one of the four dimensions of spacetime. String theory claims there are more dimensions, but that’s a side issue.

We move through the three space dimensions. SR shows that our motion affects how we perceive motion and time.

We measure our own motion within our frame of reference. In fact, measuring motion defines a frame of reference. We ride in a car sitting still. But the car moves at 100 kph along the highway, so we are moving at 100kph along the highway, too. And the Earth spins, and orbits the sun, and the solar system moves within the local star cluster, which moves within the spiral arm that orbits the Galaxy. The Galaxy spins, and moves towards Andromeda. And so on.

Within us, the blood moves, air moves, muscles expand and contract, molecules move about and react with each other. Within larger molecules, groups of atoms move this way and that as the molecule changes shape. The atoms themselves move, and within the atom, the electrons and nucleus move. In fact, they move so much that the best we can do to specify their motion is to describe it as a cloud of possibilities, using a wave function that’s said to collapse when we measure those motions.

Heisenberg says the more precisely we measure the motion of electrons etc, the less precise the measurement of their location. Or the more we know about how the electron moves, the less we know about where it is. Which interpretation of the math is correct? I don’t know. Take your pick.

Why do I emphasise motion? Because all motion “takes time.” That is, any change in a space dimension entails a change in the time dimension. This seems to me the intimate integration of space and time that Einstein formalised as General Relativity. I hope this interpretation Einstein’s insight is correct.

So the other day I was thinking about time as a dimension, for about the 777th time. It had occurred to me that if we move through space, what would it mean to say that we move through time?

We normally think of time as “passing”, and point to clocks that measure that passage one tick at a time. Where a tick is a small motion of something. In the international standard of time  measurement that tick is a single cycle of the vibration of caesium:

The second [...] is defined by taking the fixed numerical value of the caesium frequency, ΔνCs, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be 9192631770 when expressed in the unit Hz, which is equal to s−1.[1]

That “.... one tick at a time...” is either evidence of our brain’s conceptualising limits, or else proof that time is real in the same sense that space is real. Take your pick. I mention this puzzle because recently Carlo Rovelli and other physicists have wondered whether time is real or an illusion. Maybe space is all there is, and the feeling that time passes is created by our brains. The question may have been instigated by the awareness that being aware means being aware of time passing.

We speak of “spending time”, and continue with the terrifying thought that once we’ve spent a chunk of time, we can’t (unlike with money) earn an equivalent chunk of time to replace what was spent. Heraclitus supposedly said that we never step in the same river twice, since the water has flowed on between steps. Time, he said, is like that river. There’s a hymn that includes the phrase “time, like an ever-flowing stream”, which is a cliche by now. These ways of thinking all imply that time is some kind of entity. It’s not like space. Which may be why we have trouble dealing with Einstein’s concept of spacetime.

Does thinking of time as something we move through solve these conceptual problems? Maybe. Let’s try it.

Begin by supposing that there’s more than one time dimension. We happen to be confined to a line within that space, our timeline. Specify a frame of reference and you specify a timeline. We move through time along that line whenever we move through space. And as I’ve sketched above, we are always moving with respect to some other entity. Utter repose is impossible. Even death entails motion: as our body decays, its bits and pieces move in all directions, transported by the critters that eat them or the wind and water that carries them away. The skeleton that remains moves with the Earth.  

Now suppose that we could move off that timeline, in any direction, sideways, up and down, at an angle, in a circle. Just as in space we can take a shortcut, we could take a shortcut in time, and arrive at a future point on out timeline without passing through the intermediate ones. Time travel the would be moving off our timeline, moving around in time, and rejoining our timeline.

If time is multidimensional, would there be some way of writing a formal theory that could be tested? I’ll leave that up to the people who can handle the math. But the concept could work as a premise for sci-fi story. I’m sure the idea has occurred to someone else. If not, I hereby claim first invention (or discovery), and grant a non-transferable licence to anyone who wants to use it. Just give me a cut of the royalties.

© W. Kirchmeir

Existential Physics (Hossenfelder 2022)

     Sabine Hossenfelder. Existential Physics (2022) Hossenfelder has made a YouTube reputation as a disturber and explainer. Search for her videos; they’re fun and enlightening. She believes that modern physics is in crisis because it claims more insight and understanding than is warranted by experiment and observation, especially when it comes to dark matter and energy. The theories, the sets of interlocking equations, describe what’s measured, but for consistency’s sake, theorists have added entities that haven’t been observed to interact with the entities that we know about. In her Warning (Foreword), she says, “Science has limits, and yet humanity has always sought meaning beyond those limits.” Quite so.
     Then Hossenfelder goes on to show how science can inform some of the answers to the questions that exceed the limits of science. Science can clarify and disambiguate some of those questions. For example, do we have free will? The scientific answer (summarised) is: “No, if by free will you mean the ability to choose without being subject to the laws of physics.”

     For choosing is a brain-function, and brains function according the laws of physics. This fact has funked recent philosophers, who see no way out of the answer. But there is one: when we deliberately choose we figure alternatives, and weigh their desirability. We may choose differently than we chose in the past or will choose in the future. We will often choose differently than others choose. Thus, while our choices may not be freely willed, neither are they automatic. We aren’t automatons; we are agents. But we can’t choose without preferring one alternative to the others. Since our preferences are shaped by our genetics and our experience, in that sense, the choice is not “free”. However, we can choose to change our preferences. Odd, that. Is the choice to change our preference free or not? At the neurological level, I think no. At the psychological level, I think yes. And then there's  the spoiler question: How would you distinguish between free and determined choice? To choose is to exercise preferences and desires. Even if those preferences and desires are determined, the choice could still be free. You just can't tell.
     Hossenfelder does fall into what I think is the common philosophical error of physicists: She believes that physics reveals reality as it really is. Or at least that it is closer to doing so than the messier, less abstract sciences such as chemistry, biology, psychology, and so on. She reminds us that every "emergent property" that biology describes can be explained by chemistry and physics, and that everything that chemistry describes can be explained by physics. Neurology is solving some of the puzzles of psychology by showing how brain function varies with different behaviours, and emotions. Or at least suggesting how to reframe the puzzles.
     In short, she says, no so-called “emergent” phenomenon has (so far) been found to be inexplicable by the lower level from it which supposedly emerged. AFAIK, she’s right. But since the more abstract theories are derived from and explain the less abstract ones, that’s not, I think, a surprise. Logically, the more abstract explanation is equivalent to the less abstract one, just simpler.
     As I see it, physics describes the structure of reality. Einstein’s space-time makes this absolutely clear: What we observe depends on where in space-time we are and how we are moving relative to other entities. Special relativity describes how one observer’s worldview (measurements) is precisely transformable into another observer’s worldview: a clock runs fast from one POV, runs slow from another, and we can calculate exactly how much the measurements differ. (These calculations are necessary for GPS systems to function.) General relativity (GR) describes the geometry of space-time, within which we entities live and move and have our being - and observe each other within the constraints descibed by special relativity.
     Quantum mechanics (QM) shows that what we observe depends on the event’s context: Electrons behave like particles in some contexts, and like waves in others. Or better, wave equations describe some electron behaviours, and particle equations describe others. None describe electrons. And those equations are the best descriptions we have, so far. There are probably better ones “out there”, and maybe they’ll be discovered. But not in my lifetime, I think. Bummer.

     The fact that GR and QM cannot (at present) be reconciled should not surprise us either, I think. Both are highly abstract descriptions of what’s common and different in our perceptions of reality. Our experience of reality is a simulation created by our brains. We can compare each other’s perceptions, and note whether we perceive the same differences and similarities. That’s the beginning of science, and it’s already one level of abstraction away from the simulation which is our experience of the world around us. But that simulation is itself an abstraction, constructed (computed?) by our brains from the sense data delivered  to it, data that already processed by the sensors. The simulation is sufficiently accurate that we can navigate the world, get our food, find our mates, etc. It must be structurally similar to reality, else we could not survive. It may make sense to say that the topology of our experience (the simulation) must be similar enough to the topology of reality to enable our survival. I don’t know enough about topology or brain function to be able to say. I also haven’t a clue how the brain’s simulation becomes what “I” experience. I suspect it’s because “I” is part of the simulation, probably the essential part, but how would one test that notion?
     I enjoyed this book, because (as the above may show) it prompted rethinking many of my ideas. I will read it again. Hossenfelder is an excellent explainer.
     Recommended. ****

Why Right and Left are (almost) indistingushiable.

  Martin Gardner. The New Ambidextrous Universe (rev. ed. 1990) A revised version of what  Gardner understood of physics in 1990. He acknowledges the book is outdated (evidence for the Higgs boson has since been found, for example), but it’s still a good overview of the Standard Model and its implications. The title refers to the arbitrariness of the terms Left and Right. Our usage is purely conventional. Without a face-to-face encounter, even a picture can’t define the convention, since one has to know it in order to reproduce the picture the right (!) way round. That would severely limit attempts to communicate with aliens. Left-right happens to be a necessary category of symmetry, without which theories of physics don't make sense.

    Gardner writes well and clearly, with a sly wit that sometimes breaks through his earnestness. One does need at least a high school knowledge of physics to grasp some of the explanations, but the central thesis is accessible to anyone.

     Oh, about "almost indistinguishable": I don't understand it, but it seems to have something to do with C-parity. Clarifications and corrections desired.

    Recommended ****

Consciousness and Reality (essay)

 Consciousness and the real world

The New York Times recently reprinted an essay by Galen Strawson. Read it here:
Strawson Essay

I don’t usually review articles, but this one is I think worth reading. Strawson’s argument reverses the commonplace conception of what we know and don’t know about reality.

Briefly, this is how I interpret his thesis: The Hard Problem is not Consciousness. It’s Physical Reality. Physics offers an incomplete view of reality. It tells us how reality works, but it does not and it cannot tell us what reality is. This point was commonplace 100 years ago, Strawson writes, but it has gotten lost in the recent discussion of consciousness. Stephen Hawking makes this point dramatically in his book A Brief History of Time. Physics, he says, is “just a set of rules and equations.” The question is what “breathes fire into the equations and makes a universe for them to describe?” What is the fundamental stuff of physical reality, the stuff that is structured in the way physics reveals? The answer, again, is that we don’t know — except insofar as this stuff takes the form of conscious experience.

In a post about Schrödinger’s Cat, I made the point that what physics offers us is a model of reality, of whatever-it-is that’s out there. Models are inherently limited. Whether built of equations or of plastic and metal, a model is not the prototype. It’s not even a replica of its prototype. (1) A model behaves in some limited respects like its prototype, which can be useful. A bridge design, that is, a conceptual model of a bridge, allows us to calculate the stresses well enough that the real bridge built according to that design will carry traffic without falling down. (2)

The model of the bridge can exist in several media: drawings, sets of equations and algorithms, physical objects made of wood or plastic or metal. None of them is the actual bridge, and none of them captures the total reality of the bridge. But, says Strawson, we can know the real bridge, “insofar as [the bridge] takes the form of conscious experience”. Indeed we can. We can look at it, we can hear the wind make the supporting cables hum, we can feel it shake as a truck passes over it, we can feel the texture of the railings as we hold on to them. That, says Strawson, is the physical reality that our theoretical models can never capture. But our conscious experience is what we know, and all that we can know directly of physical reality.

So the hard problem is the problem of matter (physical stuff in general). If physics made any claim that couldn’t be squared with the fact that our conscious experience is brain activity, then I believe that claim would be false. But physics doesn’t do any such thing. It’s not the physics picture of matter that’s the problem; it’s the ordinary everyday picture of matter. It’s ironic that the people who are most likely to doubt or deny the existence of the conscious self (on the ground that everything is physical, and that consciousness can’t possibly be physical) are usually also those who are most insistent on the primacy of science, because it is precisely science that makes the key point shine most brightly, the point that there is a fundamental respect in which the ultimate intrinsic nature of the stuff of the universe is unknown to us — except insofar as it is consciousness.

 

 

Strawson implies that reality is consciousness.  I’m not sure that I agree with that. But his stance has at least two advantages over the notion that Consciousness is the Hard Problem.

First, it reminds us that physics itself is motivated by a desire to make sense of our conscious experience. The fact that our models become ever more abstract, that  they become “sets of rules and equations”, is a side effect of the experimental process that we believe yields objectively true insights. (3)

Secondly, it validates the empirical stance. We test accounts of reality, no matter how abstruse or abstract, against our own experience. “Truth” is the feeling we have that what’s being said corresponds to reality as we perceive it. This applies as much to the most mystical theology as to the most concrete engineering problem. It applies as much to the silliest confabulations as to the most tested and proven theory.

“The truth is out there” undergirds all our sense of reality. But we know the truth only by sensing congruences between different experiences, both remembered by ourselves and shared with others. Whatever is “out there” will forever be a mystery. That was Plato’s point in his image of the cave. His mistake was to believe that reasoning could access the reality outside the cave. He began the line of thought that ends with the blithe assumption that the “sets of rules and equations” describe reality not only more accurately but more completely than the accounts of our subjective experience.

There’s an irony here: The more we try to understand the nature of reality, the more we retreat from it. As Russel commented, in mathematics we know whether what we are saying is true, but we don’t know what it’s about; while in poetry we know what we are talking about, but we don’t know whether what we are saying is true.

With all its quirks and imperfections, the world presented by our conscious experience is the only reality we know.

Footnote 1: There is a difference between a scale model of a steam locomotive that runs on a steam, and a full size replica of the same locomotive. The model’s boiler, for example, will have to have thicker than scale walls, else it cannot sustain the necessary steam pressure. The model will not accelerate and decelerate in scale proportion, because its power to mass ratio will be different. See https://en.wikipedia.org/wiki/LNER_Peppercorn_Class_A1_60163_Tornado

Footnote 2: Nineteenth century theories of bridge behaviour were incomplete enough that many bridges fell down, and many people died. The real bridge does not behave exactly as modelled, thus giving graduate students in engineering lots of opportunity to observe them and refine the models.

Footnote 3: Quoting Bertrand Russell, Strawson writes:  “We know nothing about the intrinsic quality of physical events,” [Russell] wrote, “except when these are mental events that we directly experience.” In having conscious experience, he claims, we learn something about the intrinsic nature of physical stuff, for conscious experience is itself a form of physical stuff.

 Edited 2022-09-23

Two by Feynman: Occasional pieces add up to an autobiography

 

Feynman explaining one of his diagrams, and a couple of helpful hints for his students

Richard P. Feynman. Surely You’re Joking, Mr. Feynman? (1985) Feynman’s memoirs, recorded, assembled and edited by his student and friend Ralph Leighton.

Feynman is one of my heroes. Ever since I heard his anecdote about how his father showed him the difference between knowing words and knowing things, I’ve been hooked on his straightforward common sense. I don’t understand his contributions to quantum mechanics, because I can’t do the math of quantum mechanics. But I understand that his approach to making sense of the world works.

He was an intensely curious man. If he came across something he didn’t understand, he tried to figure it out. The puzzles that he loved most were about physics, but he also strove to make sense of art (he learned to draw, which trained his perception well enough that he could tell the difference between a Raphael and painting by one of Raphael’s students). He wanted to understand dreams, and how we can make images when we don’t have sensory stimuli to prompt perception (he died before fMRI scans provided the basis for an answer). He wanted to understand hallucinations, and spent several sessions in Dr Lilly’s sensory deprivation tanks.

He liked mastering gadgets, earning pocket money as a boy by fixing broken radios. He wanted to master drumming, so he practiced, practiced, practiced. He did the same with combination locks used on file cabinets at Los Alamos when he worked at the Manhattan Project, demonstrating how insecure they were, which eventually prompted the authorities to buy better safes. (He tells how a big-wig colonel who wanted the best safe for himself didn’t bother resetting the combination from the factory setting, thus proving well before computers that the greatest weakness in any security scheme is the human being). When he discovered something that mattered to him, he changed his behaviour: when he was still a young man he stopped drinking because he didn’t want to screw up his thinking machine.

He didn’t suffer fools gladly, especially when they came on stage with pompous claims to scientific rigour. His Caltech commencement address dissected “cargo cult science”, of which he found depressingly many examples in the social sciences. He didn’t like what receiving the Nobel Prize did to his reputation: he found his fame was used by many institutions to attract audiences. To have a Nobelist as a guest speaker reflected glory on the sponsor. Feynman hated that.

I’ve heard Feynman speak on recordings and in videos available on YouTube. Reading this book, I heard his voice again. A wonderful book by a wonderful human being. ****

Richard P. Feynman. “What Do You Care What Other People Think?” (1988) More memoirs, lectures, and anecdotes, as well as letters, sketches, and reports. Part 1 includes the title piece,  Feynman’s memoir of his first wife Arlene, who died of tuberculosis of the lymph glands. Part 2 is a dossier of his participation in the Challenger investigation. His key insight, that the rubber sealing rings in the booster joints could not adapt to cold temperatures, was prompted by his Pentagon minder, a General Kutyna, who was savvy in the ways of Washington, and so was able to give Feynman the hint that set him on the trail. The book also includes photographs, badly printed, but good enough to get an impressions of people and the occasion.

Two things stood out for me. First, that Feynman was a private man, who took great care in showing only what he wanted to show of his inner life. His love for his wives and his family nevertheless comes through, as do his essential playfulness, and his fierce love of the truth. Then there’s his integrity. He won’t fudge the truth as he sees it, nor will he pretend certainty where there is none. A remarkable man. ****

Update 2026-05-11: I've come across a video supposedly showing Feynman explaining why getting to Mars is impossible. It was generated using AI.  Th explanations are valid, but they're not quite in the style of Feynman. "Feynman" is shown in colour, but his facial expressions are limited, and he doesn't move around like Feynman actually did. Beware: there will be many more of these.

 

Once more with feeling: Climate Change (longish read)

A comment based on my current understanding of the science

     Climate is a chaotic system. It consists of a web of interconnected feedback loops. For example, cloud cover cools the ground below, which reduces evaporation, which reduces the amount of water in the air, which reduces the odds that there will be rain. However, water doesn’t cool as rapidly as the ground, so evaporation from large lakes continues, which increases the amount of water vapour in the air, which increases the odds that there will be rain. Which is why cloud cover over the Great Lakes usually signals rain, while cloud cover over the Prairies does not.

     These links between feedback loops makes it difficult to precisely model the weather and hence the climate. Some feedback loops cancel the effects of other loops, and some feedback loops enhance the effects of other loops, and all of them are entangled with one or more other feedback loops. Such systems are characterised by non-linear relations between causes and effects. Small (sometimes very small) changes in some factor can become magnified into huge effects. Hence the sometimes rapid development of afternoon thunder storms after a bright, cloudless morning.

     A chaotic system cycles through a series of states ("the seasons") that vary within some range but average out over time (average annual seasonal temperatures, etc.) This average is called the attractor. "Regression to the mean" is a common effect: Think of a baseball pitcher's performance over time. Pitching is the influenced by many factors, most of which affect each other. The pitcher's performance is a chaotic system: sometimes he's hot, sometimes he's not, most of the time he performs near his average level.

     Chaotic systems can change radically. If some factor or factors exceed some limit (too much or too little), the whole system will shift into a new series of states, some or all of which are radically different from the previous ones. Hence climate change, or global warming.

     There is no question that burning fossil fuels has increased CO2 concentration in the atmosphere, now (about 400 parts per million) coming closer to double the concentration of pre-Industrial Revolution levels (about 280 parts per million). (See this graph) This is having an effect on climate, the  annual weather cycles. The important questions IMO are:
a) How fast is this happening?
b) Is it happening faster in some climate zones than others?
c) How far will it go?

     Answer to a) Unknown, but climate models so far have understated the expected changes. This is shown in:
     Answer to b) Yes. For example, the Arctic is warming about twice as fast as the temperate zone. Predictions of the extent of summer sea ice have repeatedly underestimated the numbers. The general trend is melt beginning earlier and proceeding more quickly than predicted by the models available at the time. Thus, there is less sea ice, and it’s thinner. The last ten years or so have seen record ice loss almost every year.
     Answer to c) Nobody knows for sure how far climate change will go. Models are continually updated and tested with new data, both current and historical (from Greenland ice cores, for example). As these models get better, they imply what I think are several important conclusions:

1) Climate can change very rapidly from one normal limit to the other. For example, the Little Ice Age, a fairly sudden cooling of the northern winter, which among other things destroyed the Viking settlements in Greenland.

2) Seasonal weather patterns can change in opposite directions, for example, rainfall shifting from winter and summer, hence wetter springs and falls, and dryer summers and winters. This means flash flooding and drought when neither was common in the past.

3) Weather patterns can change from historic averages within two or three years, for example the now five-year drought on the West Coast of the USA.

4) There's a lag between the warming effects of CO2 and climate change because of heat-sinks, chief of which is the ocean: Over half of the recent rise in ocean levels is caused by the expansion of water as the oceans warmed up.

It's true that climate models aren't good enough to satisfy the non-scientist's yearning for certainty. But I think the certainty is higher than required in a civil law case ("balance of probabilities"), and close to that required in a criminal case ("beyond reasonable doubt”, emphasis on "reasonable").

(Revised 2020 09 21)

How to Misunderstand Physics

 On Metaphor and Misunderstanding
Why physics is misunderstood

Originally part of  Usenet post Re: Empirical Utility of Dualism Posted: Dec 2, 2005 11:01 PM . Wolf Kirchmeir said: [...]
The three types of quarks could've been called anything at all. The terminology was preceded by the mathematical models that confirmed and predicted observations. The theoreticians could have used Greek letters, like they did for the tau, the mu, etc. Or Egyptian letters (which IIRC was actually suggested.)

Hint: learn the math.

"Quark" is borrowed from Joyce's Finnegan's Wake. Joyce borrowed the word from the German, wherein it refers to a kind of cottage cheese.

Me, I'd've proposed "flush" and "skint"; "womble" and "gronk"; and "tvepji" and "bsanji".

But nobody asked me. :-(

[A response to this post implied that naming the flavours of quarks up/down, top/bottom would lead to a “more interesting understanding” than the terms I suggested. “Flavours” is of course another metaphor. My comment on that post follows:]

The terminology was chosen to be deliberately arbitrary. The intent was to avoid what was called "a more interesting understanding," since quarks of all three types simply aren't like anything we can understand. Only the mathematical models make true sense of the phenomena they refer to. Ordinary-language accounts are metaphors, and like all metaphors they obscure as much as they illuminate.

It's somewhat like reading music. Some people can "hear the music" when they read the score, others (like me) can more or less accurately sing or play it, but for many a written score is just so many black spots, and they can't even "follow the score" when they hear the music played. When it comes to the mathematics of sub-atomic physics, very few of us can even follow the score, let alone pick out the tune or hear the music just by looking at the score. The physicists, bless their hearts, try to make their theories understood, but what their well-intentioned attempts actually do is foster a great deal of misunderstanding.

Addendum 2015-06-02: I think the misunderstanding applies to the physicists, too. I don’t think it’s useful to say that photons are waves or particles. All we know is that in some situations, we can use wave equations to describe their behaviour, and in other situations we can use particle equations. To say that the “wave function collapses” I think merely means that the probabilities described by the wave function are replaced by certainties when we observe/measure the consequences of some interaction. To refer to entities that interact as some entities that exist in and of themselves apart from the interactions is I think a mistake. All we can ever know is the interactions.

The cost of externals: An accumulating debt

Steel, concrete, and climate change: the cost of zero-priced externals

New Scientist (November 16-22, 2019) has published an article showing the high carbon cost of making steel and cement, the two raw materials that make our techno-civilisation possible.

The article reports several projects to reduce the carbon cost. One is to use hydrogen instead of coal in blast furnaces. “If the economics work out”, that is. All these projects are priced at the actual costs of development and deployment. This makes them look expensive compared to traditional methods of making steel and cement. (1)

Steel and concrete are a prime example of how traditional economics has misstated the costs of our life style. Neo-liberal (Chicago school) economics prices externals at zero. Thus steel and cement have seemed to be cheap materials for making the things we want. In fact externals do have a price. We just haven’t bothered to work out good methods for pricing them, still less for paying them. (2)

As a species, we have evolved to use our environment as a freely available resource for making what we want, eg, spears. The cost of making these tools was the labour of making them. The cost to the ecosystems was ignored. Our ancestors didn’t notice or care that the tree they destroyed to make sticks for poking game animals to death meant that the ecosystem had to make another tree. As long as humans were a small component of the ecosystems, the long-term effects of our use of natural resources were minimal. (3)

However, the costs of externals accumulate. If we don’t pay them, they become a debt. Mother Nature always collects her debts. We either spend our resources now to mitigate and if possible reverse climate change, or we will pay with the loss of property and life.

(1) Concrete is made by using cement to bind the sand and gravel particles together. This process requires CO2, so some of the CO2 used to make cement is recovered from the air.

(2) Zero-priced externals mean that the goods are under-priced. The market works efficiently if and only if prices express costs accurately relative to each other. Mispriced goods distort the market, which leads to market failure.

(3) Human effects were actually not balanced by ecosystem recovery: archeologists have found evidence that agriculture began the climate warming cycle at least 7,000 years ago. Also, many local or regional extinctions of animals were caused by humans.

David Feldman. When Do Fish Sleep? (1989) Second in Feldman’s series of “imponderables”, which attempt to answer those nagging questions that  our high school classes didn’t cover. Such as the title question. Do fish sleep? Well, they do exhibit episodes of near-zero activity, which I suppose could be seen as sleep. Wrasses cover themselves in a thick blanket of mucus, not to keep warm, but to obliterate their odour, which would attract predators.
     A nicely done potato chip book, with an index, which makes it a useful reference for the times when you can’t be bothered to start up your device and search online. Online searching for fishes’ sleep patterns offers so many hits that deciding which one to open may be more trouble than opening the index in this book and finding the answer on page 161 to 162.
     I like these books (and many others like them, for example the urban legend compendiums), hence ***

Perception: Colours

Fragment of a conversation in a newsgroup. The book did not figure inthe conversation. I think it supports my stance that colour is in the brain.

[A]
  I was once asked "How many colors are there?". A difficult question,   which many people can't answer, they've confused "how many colors" with   "how many WORDS for colors". 2^24 (16,777,216) is a better answer than that.

[B]
 I agree with 2^24, that seems to be as much as the eye can distinguish.

[C]
 Which doesn't mean that reality is so limited. Note that some animals see better than humans, which isn't relevant either.

[Me]
There's a difference between colours as measured by a spectrometer and colours as perceived by a human. Eg, there is no such colour as "brown" in the spectrum. Or "pink". Or "grey". Or etc.

The 2^24 number of colours is the combinations of colour data used to display colours on a screen. Whether there are actually that many colours displayable on a given screen is another issue: screens vary quite a bit in quality, though much less nowadays than they did in the Olden Days. And whether a human can distinguish them all is another issue. And whether they can replicate natural colours in all weathers is another issue again. As anyone who's tried to make a photo "look right" knows.

As for "see better", that's not a clear concept either.

When it comes to perception, the only thing we can objectively measure or observe is what colour (or other sensory) differences the animal can distinguish. While it's true that bees can distinguish ultraviolet wavelengths, that doesn't mean they "see better". They see well enough for their survival, and that's what counts.

Or take frogs. Judging by their behaviour, they can't see fly-sized blobs unless those blobs move. I surmise that's similar to human peripheral vision, which is much better at distinguishing moving blobs of light than still ones.

Bottom line: what's "out there" isn't what we think it is.

How efficient is a car?

The Second Law of Thermodynamics puts an upper limit on the efficiency of a heat engine. As I understand it, the most efficient heat engine is a Carnot cycle engine, named after Sadi Carnot, who worked out the  maximum theoretical efficiency of any heat engine. It’s (1- Tc/Th), where Tc is the temperature of the cold side of the engine, and Th is the temperature of the hot side. Heat flows from the hot to the cold side, and on the way some of it can do useful work.

So how much work can a gasoline engine do?

In real life, friction and other factors reduce the efficiency of the engine. Long years of experience with gasoline engines shows that typically they operate at about 25% efficiency. That is, of every 100 litres of fuel you put in your tank, about 25 litres move the car and what’s in it. The other 75 litres are wasted in the form of exhaust gases, friction, heating the engine, etc.

That’s the efficiency of the engine. It’s not the efficiency of the car.

To calculate the efficiency of the car we need to know the total weight of “the car and what’s in it”. You, the driver, are in it.

Let’s say you are a typical Canadian male and weigh about 200 lbs (90kg). A car itself typically weighs about a ton (2000 lbs, or 900kg). Together, you and the car weigh about 2200 lbs, or 1 tonne (1,000kg). So you weigh about 10% of the total.

So only about 10% of those 25 litres that move the car and you actually move you. Or, thinking about the fuel in the tank, out of 100 litres, 2.5 litres are used to move you down the highway.

That means the overall efficiency of the car as a means of transporting its lone driver is 2.5%.
Since fuel costs money, that means of every $10 you spend, 25 cents will pay for your transportation, and the other $9.75 pay for moving the car, wearing down its parts, and heating the air.

You can increase that efficiency. A lighter car is more efficient, because you make up a larger fraction of the total weight. A car loaded with passengers and their gear is also more efficient, for the same reason. A vehicle that carries a lot of passengers and a lot of gear, like a van or a bus, will be even more efficient. However, with just the driver, a van or bus will be less efficient. A pickup truck, which weighs considerably more than a car, will always be less efficient.

From a selfish point of view, one should buy the lightest car one can use, and use it as little as possible. From a social point of view, one should probably not use a car at all, or only when absolutely necessary.

Economics 201: Thermodynamics and efficiency

 Thermodynamics and economics: Why a car is the most expensive mode of transport.

A typical gasoline engine in a car runs at about 25% efficiency. That is, the energy in 1 out of every 4 litres (or gallons) of fuel in the tank does “useful work”. The energy is mostly converted to waste heat, but some is wasted in "internal losses", such friction in the engine and transmission, pumping coolant etc. (Efficiency in the lab can be much higher, but we’re talking real-world here, not lab conditions).

The “useful work” consists of moving the car. So about 1 of 4 litres of fuel is used to move the car and its driver. Let’s assume the car plus driver weighs a tonne (1000kg), of which the driver weighs 90kg. Since a litre is 1,000ml, the system burns 1ml of fuel per kg of weight. Of this, 90ml will be used to move the driver. The rest (910ml) is used to move the car. So out of a total of  4,000ml of fuel, 90 ml is used to move the driver. That’s approximately 1/4%.

Therefore: If the fuel costs $1/litre, you’ve spent $4 to move yourself, of which 1 cent's worth of fuel moves you, 99 cents’ worth moves the car, and $3 pays for internal losses and waste heat. One can scavenge some of that waste heat to warm the cabin in winter, so it’s not entirely wasted.

The above calculation ignores the effect of speed, because speed increases fuel consumption overall. However, since with increasing speed an increasing fraction of the energy is used to push air out of the way, the fraction used to move the driver decreases. In other words, at most 1/4% of the fuel moves the driver down the highway.

I’ve also ignored the effect of passengers, stuff in the trunk, etc, since those merely increase total weight and hence total fuel consumption. The amount of available useful work will still be about 25% of the energy in the fuel. The fractions for moving the car and moving the people in it will change somewhat: a loaded car will transport people and their gear a little more efficiently than a nearly empty one.

But however you tweak the scenario, using a car to transport people is appallingly wasteful.

The Improbability Pirnciple: Why we don't notice the improbability of eveyday life (re-read)

 

David Hand. The Improbability Principle (2014) Suppose you’re playing bridge. You get a hand of all 13 hearts. How unusual! In fact, this deal is one of  635 013 559 600 possible hands. “Ordinary” hands are much more likely, right? Well, yes and no. The fact is that any combination of 13 cards is equally likely. The all-hearts hand is unusual only in that you notice it. A hand with a mix of values and suits looks normal, and it is, in the sense that there are only four all-suit hands, and 635 013 559 596 mixed-suit hands. But each one is unique. So each one is as unlikely to be dealt as any other. All bridge hands are equally improbable. 

     The same goes for lottery number picks.  

And when you have absorbed that fact, you are on the way to understanding Hand’s book. He explores odds and chance, our perceptions of odds and chance, and the tools available for estimating odds and chance more accurately. The exploration shows that “Coincidences, miracles, and rare events [will] happen every day”. He demonstrates several laws of probability that combine to make the improbable happen.

                                                  Ian Fleming was wrong.

    Hand’s book will help the reader realise how improbable every event is. It’s a good introduction to probability and statistics, with many real-life examples as well the standard text-book ones. It will help the reader see the world in which they live with more understanding, and I hope more curiosity. Hand writes well, his tone is conversational, he allows himself the occasional dry joke.
     Recommended. ****
     

Here’s my take on his work. It builds on his book, and other books I have read.
     Improbable events must happen, for there are long and convoluted chains of cause and effect leading up to every event. Call them event-chains. Looking forward from here and now, an enormous number of possible event-chains stretches into the future. They intersect and criss-cross in unpredictable ways. The future is a network of possible events. Any one event lies on a node, where several possible paths through the network meet. Which paths through this network could lead to events involving you, tomorrow morning, while you are having breakfast? An enormous number. You can list some of the most likely events (the cat will want to go out just before you set the breakfast table, you will fetch the cereal from the pantry, etc).

Jung didn't understand probability. Nor did he notice that "meaningful coincidence" is meaningless. What's meaningful for one person is a mere oddity to someone else, and triviality to a third.

      But there are other ones, trillions of them in fact (a meteor will crash into the garden, a storm will strip the leaves from the oak tree, two cars will collide in front of your house, the water heater will spring a leak, etc). The odds that any one of them will happen is small (the microwave will stop functioning). For most of them, the odds are very small (one of the people in the collision is a schoolmate whom you haven’t seen in twenty years). Some are extremely small (on the back seat of the blue car there’s a paperback that you donated to the Goodwill in another town seven years ago).
     One of these unlikely events will happen. True, some event-chains are more likely than others, but in general, there are far more unlikely possible events than likely ones. There are so many that unlikely events are more likely to happen than likely ones. The likely ones just happen more often.

      As with the all-hearts hand, most events are equally unlikely. Or equally unlikely enough that it makes no difference. We pay attention to the ones that we feel are strange in some way. (That's why Jung was wrong about "synchronicity".)

     Think about it this way:
     You go to buy a box of ball-point pens. Consider the event-chain leading up to your purchase. Dozens, perhaps hundreds, of people were involved in producing the raw materials, shaping them into parts, assembling them into pens, packaging them, distributing the pens to the store. Then there’s the event-chain leading up to your decision to buy the pens. Today, not yesterday. This store, and not another. And so on. What are the odds that you would buy this particular box of pens, today?
     Exactly.
     So why don’t you think of it as improbable?
     We don’t usually notice the improbability of any given event. That’s why we’re flummoxed when we do notice one.

 Another review of this book:  https://kirkwood40.blogspot.com/2016/05/the-odds-that-odd-things-will-happen.html

 

Schrödinger's Cat has Kittens

     John Gribbin. Schrödinger’s Kittens (1995) Gribbin’s follow-up to his In Search of Schrödinger’s Cat, an earlier attempt to explain quantum mechanics. Here, he begins with an overview of the weird results of experiments inspired by various interpretations of QM, and an overview of several attempts to explain the weirdness. He focusses on non-locality, as evidenced in entanglement for example. Non-locality appears to require instantaneous exchange of information: If you determine the polarisation of one electron, the other instantly “collapses” into the complementary polarisation.
     And so on.
     I’ll note in passing that Gribbin spends a lot of time debunking the Copenhagen Interpretation (CI), which he claims requires a conscious observer. I don’t think it does, but let that pass. Either way, the CI relies on the metaphor of collapsing probability waves.
     Gribbin’s first insight, with which I agree, is that interpretations are metaphors or analogies. The question is of what? Gribbin says “Models!”, by which he means theories. And fails to see that "Models" is another metaphor. But he does say a couple of useful things about the relationship between theories (or models) and what they purport to explain, in particular that they are stories we make up in order to make sense of our observations. I don’t think he emphasises enough that these stories are told in mathematics.
     His second insight is that all experiments, and hence all theories that explain experimental results, are deliberate reductions of degrees of freedom, aka variables. Hold as many variables as possible constant, and see what happens when you mess with the rest, preferably just one if you can manage it. Create a model of just one aspect of reality (whatever it is). E.g., the laws of motion don’t concern themselves with the chemical properties of the objects whose motion they describe.
     So which of the many models of reality embodied in QM and its interpretations is “true”? They all are, as far as they go. Which one goes farthest?
     Gribbin plumps for string theory, which was fairly new in 1995, and Cramer’s transaction interpretation, which hasn’t gained as much traction as string theory has. Cramer points out that a key equation in QM has two solutions, one of which implies that “waves” propagate backwards in time. Gribbin claims that this “myth for our time” resolves the paradoxes and weirdnesses of QM.
     Well, it made sense while I was reading it.
     Throughout his book, Gribbin, like other scientists who’ve offered interpretations of QM, talks as if theories are descriptions of reality. He does this even when he reminds us that any theory that works is true only as far as it goes. Thus the Rutherford atom works just fine in chemistry, which deals with the interactions of the electrons that surround the atom. Newton’s equations work just fine for small jaunts into space. The notion of a photon as a wave works for certain experiments, and not for others.
     By “works”, I infer that Gribbin means “predicts observations accurately to the desired degree of precision”. Gribbin neither states this concept explicitly nor examines what it might mean. I think he doesn’t think about what a model is. I’ve built models, so I’m acutely aware that a model is not a replica of its prototype. You can get close, as with a model steam locomotive that operates on steam. But its boiler will have thicker than scale-size walls because otherwise it would be too weak to hold the necessary steam pressure. Its control handles must be bigger than scale so you can work them. And so on.
     In short, all models compromise, and in doing so they misrepresent what they model. A model is limited to the features that the modeller finds interesting, and leaves out or caricatures everything else. So if we declare that a theory is a model, just what does that imply?

     A theory is a collection of interconnected equations that describe the possible states of some natural system and how it may change states. In this sense, a theory is a model of the system. More precisely, if it’s well enough constructed, it’s an algorithm. Input some data (say, the present position and velocity of a rocket), turn the crank, and output some data (the position and velocity of the rocket a few minutes or days or weeks from now). The simple model of rocket motion ignores the effects of wind as it rises through the atmosphere, and the effects of gravity as passes by the Moon and Mars. To fix that, more complex models are devised. Divergence between calculated and observed values require that the model be rerun with the new actual values. And so on.
     In short, the model supplies information. It tells us where to look for the rocket. It’s not a description of reality, but a recipe for acquiring knowledge. But it’s limited: The Newtonian model tells us about the rocket’s velocity and location, but it doesn’t tell us how the crew is doing, and whether they will survive. For that, we need a different model (and a rather more complicated one).
     A theory is about how we can know some things about some entities. It is not a description of those entities. Philosophically, it’s epistemological, not ontological.
     So also with QM. It doesn’t tell us what an electron is, or even where it will be. It only tells where it’s been, and where it might be if you look again. The probability wave isn’t a description of possible states of the electron, it’s a description of how likely we are to know that the electron is in any given state.
     Even if you don’t go as far down the epistemological path as I’ve gone, you still don’t know what an electron is. All we know of the electron is a list of interactions, and some recipes for predicting which interactions will be observed when and where. Those recipes are amazingly accurate. Well, they amaze people who know how difficult it is to make accurate and precise observations, which includes me. I think it’s the success of QM that tempts physicists into thinking they are talking about reality. They aren’t. They’re talking about interactions, of which observation by a human is merely one more, and which I don’t believe is privileged in any way.
     Still, the book is worth a read if you have the time. It’s a good introduction to some of the wonderful strangeness of our universe. Gribbin has continued to publish his ruminations about QM and many other topics, his website will tell you more. The Wikipedia entry includes a complete bibliography.
     Recommended, but sometimes heavy going. ***
     Reposted 2016-07-13 after accidental deletion.

 

Scientific ideas we should forget

 

    John Brockman, ed. This Idea Must Die (2015) A compilation of answers to the question, “What scientific idea is ready for retirement?”, posed on https://www.edge.org/ in 2014. Brockman arranges the answers, starting with general ones, then roughly by topic, such as quantum physics, neurology, evolution, etc, and ending with math and statistics. Often, a short sequence of essays reads like a dialogue.

     Most answers are directed at a general audience, which of course includes scientists in other fields. The writers try to explicate how the target concept causes mistakes or worse, what a better understanding would look like, and sometimes what concept should replace the target. A handful read like part of an ongoing dispute between the writer and the other specialists in the field.

     I was pleased to see that many of my objections, puzzlements, and exasperations were confirmed or clarified in these essays. One of these is the wave-particle duality interpretation of some experiments in quantum physics, which I think is a holdover from the days when observations and models made a nice clean distinction between things that rippled through, and things that bumped into, each other. QM equations show that this distinction isn’t much use. It’s nonsense to say that entities are both waves and particles. It would be like arguing that because people sometimes exhibit fear and at other times exhibit joy, that human beings are somehow both fearful and joyful all at once.

     Another of my annoyances is Schrödinger’s Cat. I’m glad to see that Freeman Dyson notes that the wave function isn’t a thing, so it doesn’t collapse. It’s statement of probabilities in some specific context. (Or conversely, it’s a context defined by a distribution of probabilities). An observation measures one of the probable states. At another time, another state will be observed. To argue that somehow all probable states exist at once is like arguing that because Jack is sometimes angry and sometimes happy when he goes to a baseball game, that therefore Jack is both angry and happy until he goes to the game.

     I found some of the best entertainment in the essays dealing with psychology. One writer attacks a concept, another assumes that same concept in order to attack another one. So what’s an non-expert to do?

     However, the overall effect of reading these essays is the somewhat depressing reminder that we all hold erroneous or misunderstood scientific ideas. They appear in news reports and TV punditry hourly, and many of them have very bad effects on public understanding and thereby on public opinion, which in turn limits politicians’ beliefs about what can and should be done.

     Misunderstanding of basic math is nowhere more obvious than in news about statistics. Case in point: This morning, I heard a report on rising rates of STDs in Alberta, a roughly 40% increase overall in the last ten years, with the highest rate increases among the young and the old, and the lowest among the middle aged. Well, without the actual numbers, rate increases are pretty well meaningless. An increase of, say, from 10 to 20 per 10,000 young would be a 100% increase, while from from 100 to 150 per 10,000 middle-aged people would be only a 50% increase. 50% sounds a lot better than 100%, right? But in this example, 50% is worse, since 50 extra cases will cost five times as much as 10 extra cases.

     The final essay, by Paul Saffo, reminds the reader that the more we know, the more unknowns we encounter. Saffo refers to Teilhard de Chardin’s noosphere, the sphere of knowledge. As it expands into the unknown, its surface increases, the contact between known and unknown increases. I developed this idea on my own many years ago, when I thought of the known as an expanding circle. 2D instead of 3D, but otherwise the same. Either way, there will never be an end to the questions we can ask. Even better, there will always be more questions to ask than have already been answered. But Socrates said as much 2,500 years ago. History echoes.

     Highly recommended, as is the website. ****

Jay Ingram. The Velocity of Honey (2003)

     Jay Ingram. The Velocity of Honey (2003) Another collection of essays about the Science of Everyday Life. Ever wonder why honey piles up on your toast as it flows off the spoon? Or why some people are able wake up pretty close to the time they want? Or why you can skip stones on water? The answers are out there, but most of them are incomplete, and lead on to other puzzles. Everyday physics and chemistry is much more complicated than the simplified models of reality that are studied in the lab. Ingram is one of the best popular science writers we have. This book was nominated for the 2003 Science in Society book award.
     The chapter on why bread always lands buttered side down alone is worth the price: the table is just high enough that the toast rotates over 90 degrees before it touches down. It doesn’t always land spread side down of course, occasionally it’s swept off the table with a spin that stabilises it. Spin is one of the main factors in skipping stones, too. Recommended ****

Schrödinger’s Cat (again): Reality is interactions

     Schrödinger’s Cat (again)

A recent issue of New Scientist had a series of articles on Chance. One of these cited quantum physics (QP) to make the point that the universe is fundamentally random. No problem with that, but the reference and a New Yorker cartoon once again made me think about Schrödinger’s cat.

 I can’t do the QP math, but I do understand what QP has shown: that at the atomic level, events happen at random, there are weird linkages between events, that the elementary entities each may exist (if that is the word) in any of a small suite of states, that measurement of one property or state will destroy information about another property or state, and so on. In practical terms, this means that at the most fundamental level we can at best specify probabilities. In QP, the wave-function specifies these probabilities with astonishing precision.

     And that’s where Schrödinger’s Cat comes in. Here’s Wikipedia’s description of Schrödinger’s thought experiment, which I quote because it’s beautifully concise and clear:
     Schrödinger's cat: A cat, a flask of poison, and a radioactive source are placed in a sealed box. If an internal monitor detects radioactivity (i.e. a single atom decaying), the flask is shattered, releasing the poison that kills the cat. The Copenhagen interpretation of quantum mechanics implies that after a while, the cat is simultaneously alive and dead. Yet, when one looks in the box, one sees the cat either alive or dead, not both alive and dead. This poses the question of when exactly quantum superposition ends and reality collapses into one possibility or the other.

     And here’s the pretty picture:

     Schrödinger’s Cat is one of those cultural tokens that people use to point to a presumed common notion, in this case, QP’s weirdness. Imagine, a cat being both alive and dead until you open the lid of the box and look inside!
     Wikipedia takes up the question of how to interpret the weird result:
     In the Copenhagen interpretation, a system stops being a superposition of states and becomes either one or the other when an observation takes place.
    

 That word “observation” includes a lot of assumptions, and it’s these assumptions that create the supposed paradox. It seems obvious to me that Niels Bohr is right that “observation” merely means “measurement”, and does not mean “noticed by a human being”. But I want to go beyond Niels Bohr, and alternative interpretations (see The Wiki article for more). The other interpretations are attempts to resolve a supposed paradox, but I don’t think there’s any paradox to be resolved.
     Note again the question of when exactly quantum superposition ends and reality collapses into one possibility or another. I interpret QP to mean that "superposition" is a label for what we cannot know until we measure it. But measurement is a series of interactions, the last of which triggers a stream of photons that our eyes can detect. There follows another series of interactions, which may end with our saying, “Here kitty, kitty!”

     Measurement is not a privileged interaction. All interactions will change a particle’s state. In Schrödinger's thought experiment, we may suppose that the interaction occurs when the device detects the particle emitted by the radioactive atom. But I think that's not the case. The interaction occurs when the atom decays, when something occurs inside the nucleus. If (and only if) we are able to amplify the effect of that first interaction (e.g, by detecting the radioactivity), can we say, with a good deal of confidence, that the particle was, at the moment of interaction, in some state, that the wave function describing the particle's state has collapsed. “At the moment of interaction” is the key phrase: we cannot know what the state of the particle was before that moment, and we cannot know its subsequent history, any more than we knew anything of its history prior to the measurement. We can make another measurement, in which case we may be faced with the conundrum of what exactly the particle was between measurements.

     You may infer that I don't think Schrödinger’s Cat creates a paradoxical superposition of dead/alive. You will be right.
     I think it’s the word “observation” that has misled people. It implies an observer. But there is no observer. There are only interactions. When we say we “observe” something, that statement is itself an interaction, triggered by a complex series of prior interactions. What’s more, this series of interactions is, according to QP, fundamentally untraceable, because a measurement is an interposition in the chain of interactions, and so from that point on the chain will be different than it would have been absent the measurement. The measurement changes the state of the particle, and therefore determines the result of the next interaction. By measuring it, we change the history of the particle.

      What we may wish to think of as a property of a particle is merely an interaction that is observed in some specified context. For that matter, a particle is merely a collection of consistent interactions.
     In short, reality is interactions. That's all there is.

     2015-03-27 Updated 2015-07-07