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Showing posts from January, 2018

Back to Plato

I noticed that Lumo posted on a talk by Nima Arkani-Hamed at some group of philosophs.  A-H was talking about the need to replace space time by something - and his idea of the amplituhedron. 

So he outlined the amplituhedron program, the picture that the amplitudes have so many complicated terms because the amplitudes are really volumes of a polytope in an auxiliary space and the polytope is cut to many complicated pieces in some ad hoc ways. This program interprets a scattering process as a generalization of the process where just numerical labels scatter – and their scattering means a permutation. Polytopes cut into many complicated pieces?  Shades of Plato's Timaeus, where he constructs a cosmology of the regular polytopes he knew - the so-called Platonic solids, and their pieces, taking special note of the fact that all except the dodecahedron can be decomposed into 30-60-90 triangles.

I was going to mention this on his blog, but he has me banned.  My theory is that he's af…

Really, Truly, Virtually

And as imagination bodies forth 
The forms of things unknown, the poet’s pen 
Turns them to shapes and gives to airy nothing 
A local habitation and a name. 

Such tricks hath strong imagination, 
That if it would but apprehend some joy, 
It comprehends some bringer of that joy. 
Or in the night, imagining some fear, 
How easy is a bush supposed a bear!...................Midsummer Night's Dream, Act V, Scene 1

Sometimes the pen belongs to a physicist or a mathematician.

Are virtual particles real?  Are imaginary numbers real?   How about negative numbers?

As usual, it all depends on what we mean by real.  Not many mathematicians, physicists, or engineers would quarrel with the reality of imaginary numbers, but most of us would admit, I think, that the natural numbers are a bit more "real" than all those other numbers, including the Real Numbers.

The world is constructed of such figments of our imagination, and close analysis shows that some of the most dependable realities of our…

Really?

I was reading an old post of Sabine H. which attracted a large number of comments, including a zillion from philosopher Tim Maudlin, whose article was the subject of the post. One statement of his was something like "virtual particles aren't real. They are just convenient fictions in a mathematical calculation." It turns out that the subject is somewhat controversial even among physicists. Many seem to insist that virtual particles are quite real, and demonstrated by such phenomena as the Lamb shift and the Casimir effect. Others take the more moderate tact of saying something like "it depends on what you mean by real." Thoughts?

How a Smart Person Takes Apart a Puzzle

I mean one of those little wooden block puzzles. As you figure out how each piece comes out, make sure you know how to put it back in and reassemble. How I took apart my wooden puzzle: Not that way.

Contracting Out The Government

Conservatives, especially those of the libertarian strain, fell in love with the idea of contracting out services paid for by the government. Not only did this get rid of a whole flock of pesky civil servants, but it also provided a convenient way to funnel cash into the pockets of wealthy people who could reward politicians. Britain pioneered this trend and the US is following hard in its footsteps. Andrew Bastani, writing in The New York Times, says the model is collapsing. Last Monday Carillion, a Wolverhampton-based infrastructure and facilities management company, went into liquidation. The company has become an emblem of Britain’s public sector reforms over the last two decades, and its collapse represents a signal moment for the country.A series of "reforms" reduced the size of the bureaucracy by contracting out work the government paid for and used to do. This was part of a wider trend: In the five years following 2010, state money spent on outsourcing — contra…

Anaximenes was the Man

Anaximenes is the third of the Milesian philosophers who actually seem to have invented philosophy from scratch, in that they sought naturalist explanations rather than supernatural ones. As with his predecessors, Thales and Anaximander, most of what we know about his thought comes from later philosophers, like Aristotle, who criticised it. Anaximenes is most famous for believing that the basic substance was air, and that everything else was made up of it through condensation. At first thought, I found this silly, but on second thought, not so much. Suppose a modern time traveling cosmologist found himself in ancient Miletus, and wanted to explain his science to his fellow citizens. What might he tell them? Maybe something like "In the beginning there was a hot dense energy plasma." Of course nobody would know what energy or plasma was, so he might try to cast his discussion in terms of something more familiar, like air. His fellows likely knew that water existed in…

Collapse

Interstellar molecular clouds of dust and gas exist in a quasi-stable balance between self-gravity and internal pressure. If the mass and density are large enough, and the temperature and pressure low enough, they can collapse to form stars, usually in clusters of a few dozen to a few thousand. Both gaseous and magnetic pressure can be factors. Various factors can trigger collapse, including shocks from collisions with other interstellar clouds, passing through one of the spiral density waves that give spiral galaxies their names, or the shockwave of a nearby supernova. Once a collapse starts, it can become irreversible, as gravity gets stronger as the cloud shrinks. The cloud will heat up as a result of the collapse, but if it contains plenty of dust, it can radiate that heat away in the infrared. Actual stellar formation seems to take place in localized regions of overdensity called cloud cores. Because the molecular clouds are turbulent, individual pieces are likely to have …

White House Shithole

It's not news that Trump is a vulgar man with racist tendencies. Nevertheless, I don't think that the infamous "shithole countries" remarks are best understood as racist. The real disdain, I think, is for poor countries and poor people - the kind who can really benefit from coming to the US and are desperate to do so. Unfortunately, this kind of loose cannon remark is exactly the thing guaranteed to torpedo any rational discussion of sensible immigration policies. Exactly what constitutes "sensible immigration policies" is a difficult and extremely emotional subject of course, but I think that there are a couple of principles that ought to be paramount: US immigration should be regulated for the benefit of the US and its citizens and should not violate our principles of equality under the law.

Beauty in Physics

Bee has been on a tear against the concept of beauty in physics. She has even written a book about it. It won't be out for a few months, so of course I haven't read it, but I have my doubts. My short list of beautiful ideas in physics: (a)Kepler's Laws (b)Newtonian physics (c)Newtonian gravity (d)Lagrangian mechanics (e)The Principle of Least Time (f)Hamiltonian mechanics (g)Faraday's Law (h)Maxwell's Equations (i)Planck's Black Body Law (j)The Bohr-Rutherford atom (k)De Broglie's relation (l)Schroedinger's equation (m)Heisenberg's Uncertainty Principle (n)Dirac's Equation (o)Special Relativity (p)General Relativity (q)Feynman's path integrals (r)The gauge principle Is there an ugly law that worked?

Plato Nails This One

How a state gets transformed into an oligarchy: SOCRATES: That storehouse filled with gold we mentioned,169 which each possesses, destroys such a constitution. First, you see, the timocrats find ways of spending their money, then they alter the laws to allow them to do so, and then they and their women disobey the laws altogether. ADEIMANTUS: Probably so. SOCRATES: Next, I suppose, through one person seeing another and envying [e] him, they make the majority behave like themselves. ADEIMANTUS: Probably so. SOCRATES: After that then, they become further involved in moneymaking; and the more honorable they consider it, the less honorable they consider virtue. Or isn’t virtue so opposed to wealth that if they were set on the scale of a balance, they would always incline in opposite directions? [551a] ADEIMANTUS: It certainly is. SOCRATES: So, when wealth and the wealthy are honored in a city, virtue and good people are honored less. Readings in Ancient Greek Philosophy: From T…

Soc Flop

SOCRATES: Then the same applies to the good. Unless someone can give an account of the form of the good, distinguishing it from everything else, and can survive all examination as if in a battle, striving to examine things [c] not in accordance with belief, but in accordance with being; and can journey through all that with his account still intact, you will say that he does not know the good itself or any other good whatsoever. Readings in Ancient Greek Philosophy: From Thales to Aristotle (p. 364). Hackett Publishing Company, Inc.. Kindle Edition. Of course Plato/Socrates utterly fails to give an "account of the form of the good," relying entirely on vague analogies.

Truthy

Having described his ideal state, and the series of elaborate lies it is based on, Plato/Socrates concludes that the only fit ruler would be a philosopher king. And what is the central qualification of the PK? SOCRATES: Then let’s begin our dialogue by recalling the starting point of our description of the nature that someone must have if he is to become a fine and good person. First of all, if you remember, he was led by truth,133 [490a] and he had to follow it wholeheartedly and unequivocally, on pain of being a lying imposter with no share at all in true philosophy. Readings in Ancient Greek Philosophy: From Thales to Aristotle (p. 337). Hackett Publishing Company, Inc.. Kindle Edition.

Beauty as a Thing in Itself

SOCRATES: Now, didn’t we say earlier that if something turned out both to be and not to be at the same time, it would lie in between what purely is and what in every way is not, and that neither knowledge nor ignorance would deal with it; but whatever it was again that turned out to lie in between ignorance and knowledge would? CIPACON: Are we talking about that cat again? SOCRATES: And now, what we are calling belief has turned out to lie in between them? CIPACON: Between live cats and dead ones? SOCRATES: Apparently, then, it remains for us to find what partakes in [e] both being and not being, and cannot correctly be called purely one or the other, so that if we find it, we can justifiably call it the object of belief, thereby assigning extremes to extremes and in-betweens to in-betweens. Isn’t that so? CIPACON: Whatever. SOCRATES: Now that all that has been established, I want him to tell me this—the excellent fellow who believes that there is no beautiful itself, no f…

"I'm a Stable Genius"

These wise words of the Dear Leader set me thinking about a situation that comes up every year or ten. I had a bunch of X-rays taken today and was quite intrigued by the giant CCD array being used, so I asked the tech some technical questions about it, only a few of which she knew answers for. She asked why I wondered and when I mentioned that I was currently an Astro student and interested in imaging, she said something like: "You must be really smart." Usually I'm forced to give an honest answer and admit that I'm not nearly smart enough, but Dear Leader has given me an option. I could just say that I'm a stable genius. I have spent more than a few hours in stables, and, often as not, I find that I'm one of the smarter animals present.

Not Exactly a Socratic Dialog

SOCRATES: Now, see whether you agree with me about this: if a carpenter attempts to do the work of a shoemaker, or a shoemaker that of a carpenter, or they exchange their tools or honors with one another, or if the same person tries to do both jobs, and all other such exchanges are made, do you think that does any great harm to the city? CIPCON: Huh? SOCRATES: But I imagine that when someone who is, by nature, a craftsman or some other sort of moneymaker is puffed up by wealth, or by having [b] a majority of votes, or by his own strength, or by some other such thing, and attempts to enter the class of soldiers; or when one of the soldiers who is unworthy to do so tries to enter that of judge and guardian, and these exchange their tools and honors; or when the same person tries to do all these things at once, then I imagine you will agree that these exchanges and this meddling destroy the city. CIPCON: Sounds implausible. SOCRATES: So, meddling and exchange among these three cl…

Republic

OK, I've only read the first three books of Plato's Republic, but I'm not one to let that dissuade me from an opinion. The tone of the Republic seems much different than the dialogs, possibly indicating that Plato is no longer attempting to recreate Socrates, but express his own thoughts, even though he still attributes them to Socrates. The Socrates of the Republic is far more didactic, declaiming his ideas and mostly winning the equivalent of "Well duh" from his interlocutors. I suppose we can credit Plato with the invention of the totalitarian state, at least as an intellectual concept. He argues that by systematic thought control, a few well chosen big lies, and a bit of selective pruning of the unsuitable, the ideal governors and guardians of the state can be educated and entrusted with its governance. My reaction was that this represents a woeful misreading of human nature, but one that continues to be made pretty widely even in our day - what Steven …

America's Illiteracy Problem?

Joe Scarborough has an Op-Ed in the Post today strongly suggesting that that the President doesn't read because he can't: Mika Brzezinski and I had a tense meeting with Trump following what I considered to be a bumbling debate performance in September 2015. I asked the candidate a blunt question. “Can you read?” Awkward silence. “I’m serious, Donald. Do you read?” I continued. “If someone wrote you a one-page paper on a policy, could you read it?” Taken aback, Trump quietly responded that he could while holding up a Bible given to him by his mother. He then joked that he read it all the time. I am apparently not the only one who has questioned the president’s ability to focus on the written word. “Trump didn’t read,” Wolff writes. “He didn’t really even skim. If it was print, it might as well not exist. Some believed that for all practical purposes he was no more than semiliterate. Others concluded that he didn’t read because he didn’t have to . . . He was postliterate —…

Old Times Not Forgotten

Age: Radioisotope 207Pb/ 206Pb dating of refractory inclusions (CAIs) found within chondritic meteorites, the oldest Solar System solids known, yields an age of 4.568 Gyr. Dating with other isotope systems yields similar ages. Chondrules, as well as most differentiated meteorites that originated within small bodies, solidified only a few million years later (§ 8.7). Rocks formed on the Moon and Earth are younger: lunar rocks are typically between 3 and 4.4 Gyr old, and terrestrial rocks are ≲ 4 Gyr old, although terrestrial mineral grains as old as 4.4 Gyr have been found. de Pater, Imke; Lissauer, Jack J.. Planetary Sciences (p. 512). Cambridge University Press. Kindle Edition. The ages of the refractory inclusions and the chrodrites tell us when they first solidified, almost certainly when the solar system was first condensing. From studies of regions of stellar formation, and deductions from basic physics, we know that stellar systems form in relatively dense molecular clouds con…

Planetary Migration

We like to think of our solar system as being stable, and there is plenty of evidence that the Earth's orbit has not changed a lot in the several billions of years of life's existence. It was slightly shocking then, that extrasolar planets discovered to date don't necessarily seem to have behaved this way. In particular, a number of so-called hot Jupiters have been discovered - Jupiter mass planets in very close orbits around their stars. It seems unlikely that they could have formed there, since the environment wouldn't have been cool enough for rocks and metals to condense into planetesimals. Planetary migration had been considered in theory before the discovery of the hot Jupiters, and some migration is believed to have occurred in the outer planets of our own solar system, so the discoveries were hardly impossible to fit into our theories of planetary formation. The mechanisms are somewhat complicated, and include the interactions with density waves induced …

One Socratic Gem

...the uneducated, when they engage in argument about anything, give no thought to the truth about the subject of discussion but are only eager that those present will accept the position they have set forth. Readings in Ancient Greek Philosophy: From Thales to Aristotle (p. 187). Hackett Publishing Company, Inc.. Kindle Edition. Since I have been dissing the man, I ought to give credit now and again. Another: After this, he said, when I had wearied of investigating things, I thought that I must be careful to avoid the experience of those who watch an eclipse of the sun, for some of them ruin their eyes unless they watch its reflection in water or some such material. A similar [e] thought crossed my mind, and I feared that my soul would be altogether blinded if I looked at things with my eyes and tried to grasp them with each of my senses. So I thought I must take refuge in discussions and investigate the truth of things by {192} means of words. Readings in Ancient Greek Philosoph…