Category Archives: Science

Quantum Physics Revealed As Non-Mysterious

This is one of several shortened indices into the Quantum Physics Sequence.

Hello!  You may have been directed to this page because you said something along the lines of "Quantum physics shows that reality doesn’t exist apart from our observation of it," or "Science has disproved the idea of an objective reality," or even just "Quantum physics is one of the great mysteries of modern science; no one understands how it works."

There was a time, roughly the first half-century after quantum physics was invented, when this was more or less true.  Certainly, when quantum physics was just being discovered, scientists were very confused indeed!  But time passed, and science moved on.  If you’re confused about a phenomenon, that’s a fact about your own state of mind, not a fact about the phenomenon itself – there are mysterious questions, but not mysterious answers.  Science eventually figured out what was going on, and why things looked so strange at first.

The series of posts indexed below will show you – not just tell you – what’s really going on down there.  To be honest, you’re not going to be able to follow this if algebra scares you.  But there won’t be any calculus, either.

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An Intuitive Explanation of Quantum Mechanics

This is one of several shortened indices into the Quantum Physics Sequence.  It is intended for students who are having trouble grasping the meaning of quantum math; or for people who want to learn the simple math of everything and are getting around to quantum mechanics.

There’s a widespread belief that quantum mechanics is supposed to be confusing.  This is not a good frame of mind for either a teacher or a student.  Complicated math can be difficult but it is never, ever allowed to be confusing.

And I find that legendarily "confusing" subjects often are not really all that complicated as math, particularly if you just want a very basic – but still mathematical – grasp on what goes on down there.

This series takes you as far into quantum mechanics as you can go with only algebra.  Any further and you should get a real physics textbook – once you know what all the math means.

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The Quantum Physics Sequence

This is an inclusive guide to the series of posts on quantum mechanics that began on April 9th, 2008, including the digressions into related topics (such as the difference between Science and Bayesianism) and some of the preliminary reading.

You may also be interested in one of the less inclusive post guides, such as:

My current plan calls for the quantum physics series to eventually be turned into one or more e-books.

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Why Quantum?

This post is part of the Quantum Physics Sequence.
Followup toQuantum Explanations

"Why are you doing these posts on quantum physics?" the one asked me.

"Quite a number of reasons," I said.

"For one thing," I said, "the many-worlds issue is just about the only case I know of where you can bring the principles of Science and Bayesianism into direct conflict."  It’s important to have different mental buckets for "science" and "rationality", as they are different concepts.  Bringing the two principles into direct conflict is helpful for illustrating what science is and is not, and what rationality is and is not.  Otherwise you end up trusting in what you call "science", which won’t be strict enough.

"For another thing," I continued, "part of what goes into becoming a rationalist, is learning to live into a counterintuitive world – learning to find things underneath the surface that are unlike the world of surface forms."  Quantum mechanics makes a good introduction to that, when done correctly without the horrible confusion and despair.  It breaks you of your belief in an intuitive universe, counters naive realism, destroys your trust in the way that your cognitive algorithms look from inside – and then you’re ready to start seeing your mind as a mind, not as a window onto reality.

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Class Project

Followup toThe Failures of Eld Science, Einstein's Superpowers

"Do as well as Einstein?" Jeffreyssai said, incredulously.  "Just as well as Einstein?  Albert Einstein was a great scientist of his era, but that was his era, not this one!  Einstein did not comprehend the Bayesian methods; he lived before the cognitive biases were discovered; he had no scientific grasp of his own thought processes.  Einstein spoke nonsense of an impersonal God – which tells you how well he understood the rhythm of reason, to discard it outside his own field! He was too caught up in the drama of rejecting his era's quantum mechanics to actually fix it.  And while I grant that Einstein reasoned cleanly in the matter of General Relativity – barring that matter of the cosmological constant – he took ten years to do it.  Too slow!"

"Too slow?" repeated Taji incredulously.

"Too slow!  If Einstein were in this classroom now, rather than Earth of the negative first century, I would rap his knuckles!  You will not try to do as well as Einstein!  You will aspire to do BETTER than Einstein or you may as well not bother!"

Jeffreyssai shook his head.  "Well, I've given you enough hints.  It is time to test your skills.  Now, I know that the other beisutsukai don't think much of my class projects…"  Jeffreyssai paused significantly.

Brennan inwardly sighed.  He'd heard this line many times before, in the Bardic Conspiracy, the Competitive Conspiracy:  The other teachers think my assignments are too easy, you should be grateful, followed by some ridiculously difficult task – 

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Timeless Beauty

This post is part of the Quantum Physics Sequence.
Followup toTimeless Physics

One of the great surprises of humanity’s early study of physics was that there were universal laws, that the heavens were governed by the same order as the Earth:  Laws that hold in all times, in all places, without known exception. Sometimes we discover a seeming exception to the old law, like Mercury’s precession, but soon it turns out to perfectly obey a still deeper law, that once again is universal as far as the eye can see.

Every known law of fundamental physics is perfectly global. We know no law of fundamental physics that applies on Tuesdays but not Wednesdays, or that applies in the Northern hemisphere but not the Southern.

In classical physics, the laws are universal; but there are also other entities that are neither perfectly global nor perfectly local. Like the case I discussed yesterday, of an entity called "the lamp" where "the lamp" is OFF at 7:00am but ON at 7:02am; the lamp entity extends through time, and has different values at different times.  The little billiard balls are like that in classical physics; a classical billiard ball is (alleged to be) a fundamentally existent entity, but it has a world-line, not a world-point.

In timeless physics, everything that exists is either perfectly global or perfectly local.  The laws are perfectly global.  The configurations are perfectly local – every possible arrangement of particles has a single complex amplitude assigned to it, which never changes from one time to another.  Each configuration only affects, and is affected by, its immediate neighbors.  Each actually existent thing is perfectly unique, as a mathematical entity.

Newton, first to combine the Heavens and the Earth with a truly universal generalization, saw a clockwork universe of moving billiard balls and their world-lines, governed by perfect exceptionless laws. Newton was the first to look upon a greater beauty than any mere religion had ever dreamed.

But the beauty of classical physics doesn’t begin to compare to the beauty of timeless quantum physics.

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Timeless Physics

This post is part of the Quantum Physics Sequence.
Previously in seriesRelative Configuration Space 

Warning:  The central idea in today’s post is taken seriously by serious physicists; but it is not experimentally proven and is not taught as standard physics.

Today’s post draws heavily on the work of the physicist Julian Barbour, and contains diagrams stolen and/or modified from his book “The End of Time“.  However, some of the arguments here are of my own devising, and Barbour might(?) not agree with them.

I shall begin by asking a incredibly deep question:

What time is it?

If you have the excellent habit of giving obvious answers to obvious questions, you will answer, “It is now 7:30pm [or whatever].”

How do you know?

“I know because I looked at the clock on my computer monitor.”

Well, suppose I hacked into your computer and changed the clock.  Would it then be a different time?

“No,” you reply.

How do you know?

“Because I once used the ‘Set Date and Time’ facility on my computer to try and make it be the 22nd century, but it didn’t work.”

Ah.  And how do you know that it didn’t work?

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Relative Configuration Space

This post is part of the Quantum Physics Sequence.
Previously in seriesMach’s Principle: Anti-Epiphenomenal Physics
Followup toClassical Configuration Spaces

Warning:  The ideas in today’s post are taken seriously by serious physicists, but they are not experimentally proven and are not taught as standard physics.

Today’s post draws on the work of the physicist Julian Barbour, and contains diagrams stolen and/or modified from his book “The End of Time“.

Previously, we saw Mach’s idea (following in the earlier path of Leibniz) that inertia is resistance to relative motion.  So that, if the whole universe was rotating, it would drag the inertial frame along with it.  From the perspective of General Relativity, the rotating matter would generate gravitational waves.

All right:  It’s possible that you can’t tell if the universe is rotating, because the laws of gravitation may be set up to make it look the same either way.  But even if this turns out to be the case, it may not yet seem impossible to imagine that things could have been otherwise.

To expose Mach’s Principle directly, we turn to Julian Barbour.

The diagrams that follow are stolen from Julian Barbour’s The End of Time.  I’d forgotten what an amazing book this was, or I would have stolen diagrams from it earlier to explain configuration space. Anyone interested in the nature of reality must read this book.  Anyone interested in understanding modern quantum mechanics should read this book.  “Must” and “should” are defined as in RFC 2119.

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A Broken Koan

At Baycon today and tomorrow.  Physics series resumes tomorrow.

Meanwhile, here’s a link to a page of Broken Koans and other Zen debris I ran across, which should amuse fans of ancient Eastern wisdom; and a koan of my own:

Two monks were arguing about a flag. One said, "The flag is moving."

The other said, "The wind is moving."

Julian Barbour happened to be passing by.  He told them, "Not the wind, not the flag."

The first monk said, "Is the mind moving?"

Barbour replied, "Not even mind is moving."

The second monk said, "Is time moving?"

Barbour said, "There is no time.  You could say that it is mu-ving."

"Then why do we think that flags flap, and wind blows, and minds change, and time moves?" inquired the first monk.

Barbour thought, and said, "Because you remember."

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Mach’s Principle: Anti-Epiphenomenal Physics

This post is part of the Quantum Physics Sequence.
Previously in seriesMany Worlds, One Best Guess
Followup toThe Generalized Anti-Zombie Principle

Warning:  Mach’s Principle is not experimentally proven, though it is widely considered to be credible.

Centuries ago, when Galileo was promoting the Copernican model in which the Earth spun on its axis and traveled around the Sun, there was great opposition from those who trusted their common sense:

"How could the Earth be moving?  I don’t feel it moving!  The ground beneath my feet seems perfectly steady!"

And lo, Galileo said:  If you were on a ship sailing across a perfectly level sea, and you were in a room in the interior of the ship, you wouldn’t know how fast the ship was moving.  If you threw a ball in the air, you would still be able to catch it, because the ball would have initially been moving at the same speed as you and the room and the ship.  So you can never tell how fast you are moving.

This would turn out to be the beginning of one of the most important ideas in the history of physics.  Maybe even the most important idea in all of physics.  And I’m not talking about Special Relativity.

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