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Posts Tagged ‘Galileo

“Facts alone, no matter how numerous or verifiable, do not automatically arrange themselves into an intelligible, or truthful, picture of the world. It is the task of the human mind to invent a theoretical framework to account for them.”*…

PPPL physicist Hong Qin in front of images of planetary orbits and computer code

… or maybe not. A couple of decades ago, your correspondent came across a short book that aimed to explain how we think know what we think know, Truth– a history and guide of the perplexed, by Felipe Fernández-Armesto (then, a professor of history at Oxford; now, at Notre Dame)…

According to Fernández-Armesto, people throughout history have sought to get at the truth in one or more of four basic ways. The first is through feeling. Truth is a tangible entity. The third-century B.C. Chinese sage Chuang Tzu stated, ”The universe is one.” Others described the universe as a unity of opposites. To the fifth-century B.C. Greek philosopher Heraclitus, the cosmos is a tension like that of the bow or the lyre. The notion of chaos comes along only later, together with uncomfortable concepts like infinity.

Then there is authoritarianism, ”the truth you are told.” Divinities can tell us what is wanted, if only we can discover how to hear them. The ancient Greeks believed that Apollo would speak through the mouth of an old peasant woman in a room filled with the smoke of bay leaves; traditionalist Azande in the Nilotic Sudan depend on the response of poisoned chickens. People consult sacred books, or watch for apparitions. Others look inside themselves, for truths that were imprinted in their minds before they were born or buried in their subconscious minds.

Reasoning is the third way Fernández-Armesto cites. Since knowledge attained by divination or introspection is subject to misinterpretation, eventually people return to the use of reason, which helped thinkers like Chuang Tzu and Heraclitus describe the universe. Logical analysis was used in China and Egypt long before it was discovered in Greece and in India. If the Greeks are mistakenly credited with the invention of rational thinking, it is because of the effective ways they wrote about it. Plato illustrated his dialogues with memorable myths and brilliant metaphors. Truth, as he saw it, could be discovered only by abstract reasoning, without reliance on sense perception or observation of outside phenomena. Rather, he sought to excavate it from the recesses of the mind. The word for truth in Greek, aletheia, means ”what is not forgotten.”

Plato’s pupil Aristotle developed the techniques of logical analysis that still enable us to get at the knowledge hidden within us. He examined propositions by stating possible contradictions and developed the syllogism, a method of proof based on stated premises. His methods of reasoning have influenced independent thinkers ever since. Logicians developed a system of notation, free from the associations of language, that comes close to being a kind of mathematics. The uses of pure reason have had a particular appeal to lovers of force, and have flourished in times of absolutism like the 17th and 18th centuries.

Finally, there is sense perception. Unlike his teacher, Plato, and many of Plato’s followers, Aristotle realized that pure logic had its limits. He began with study of the natural world and used evidence gained from experience or experimentation to support his arguments. Ever since, as Fernández-Armesto puts it, science and sense have kept time together, like voices in a duet that sing different tunes. The combination of theoretical and practical gave Western thinkers an edge over purer reasoning schemes in India and China.

The scientific revolution began when European thinkers broke free from religious authoritarianism and stopped regarding this earth as the center of the universe. They used mathematics along with experimentation and reasoning and developed mechanical tools like the telescope. Fernández-Armesto’s favorite example of their empirical spirit is the grueling Arctic expedition in 1736 in which the French scientist Pierre Moreau de Maupertuis determined (rightly) that the earth was not round like a ball but rather an oblate spheroid…

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One of Fernández-Armesto most basic points is that our capacity to apprehend “the truth”– to “know”– has developed throughout history. And history’s not over. So, your correspondent wondered, mightn’t there emerge a fifth source of truth, one rooted in the assessment of vast, ever-more-complete data maps of reality– a fifth way of knowing?

Well, those days may be upon us…

A novel computer algorithm, or set of rules, that accurately predicts the orbits of planets in the solar system could be adapted to better predict and control the behavior of the plasma that fuels fusion facilities designed to harvest on Earth the fusion energy that powers the sun and stars.

he algorithm, devised by a scientist at the U.S. Department of Energy’s (DOE) Princeton Plasma Physics Laboratory (PPPL), applies machine learning, the form of artificial intelligence (AI) that learns from experience, to develop the predictions. “Usually in physics, you make observations, create a theory based on those observations, and then use that theory to predict new observations,” said PPPL physicist Hong Qin, author of a paper detailing the concept in Scientific Reports. “What I’m doing is replacing this process with a type of black box that can produce accurate predictions without using a traditional theory or law.”

Qin (pronounced Chin) created a computer program into which he fed data from past observations of the orbits of Mercury, Venus, Earth, Mars, Jupiter, and the dwarf planet Ceres. This program, along with an additional program known as a ‘serving algorithm,’ then made accurate predictions of the orbits of other planets in the solar system without using Newton’s laws of motion and gravitation. “Essentially, I bypassed all the fundamental ingredients of physics. I go directly from data to data,” Qin said. “There is no law of physics in the middle.”

The process also appears in philosophical thought experiments like John Searle’s Chinese Room. In that scenario, a person who did not know Chinese could nevertheless ‘translate’ a Chinese sentence into English or any other language by using a set of instructions, or rules, that would substitute for understanding. The thought experiment raises questions about what, at root, it means to understand anything at all, and whether understanding implies that something else is happening in the mind besides following rules.

Qin was inspired in part by Oxford philosopher Nick Bostrom’s philosophical thought experiment that the universe is a computer simulation. If that were true, then fundamental physical laws should reveal that the universe consists of individual chunks of space-time, like pixels in a video game. “If we live in a simulation, our world has to be discrete,” Qin said. The black box technique Qin devised does not require that physicists believe the simulation conjecture literally, though it builds on this idea to create a program that makes accurate physical predictions.

This process opens up questions about the nature of science itself. Don’t scientists want to develop physics theories that explain the world, instead of simply amassing data? Aren’t theories fundamental to physics and necessary to explain and understand phenomena?

“I would argue that the ultimate goal of any scientist is prediction,” Qin said. “You might not necessarily need a law. For example, if I can perfectly predict a planetary orbit, I don’t need to know Newton’s laws of gravitation and motion. You could argue that by doing so you would understand less than if you knew Newton’s laws. In a sense, that is correct. But from a practical point of view, making accurate predictions is not doing anything less.”

Machine learning could also open up possibilities for more research. “It significantly broadens the scope of problems that you can tackle because all you need to get going is data,” [Qin’s collaborator Eric] Palmerduca said…

But then, as Edwin Hubble observed, “observations always involve theory,” theory that’s implicit in the particulars and the structure of the data being collected and fed to the AI. So, perhaps this is less a new way of knowing, than a new way of enhancing Fernández-Armesto’s third way– reason– as it became the scientific method…

The technique could also lead to the development of a traditional physical theory. “While in some sense this method precludes the need of such a theory, it can also be viewed as a path toward one,” Palmerduca said. “When you’re trying to deduce a theory, you’d like to have as much data at your disposal as possible. If you’re given some data, you can use machine learning to fill in gaps in that data or otherwise expand the data set.”

In either case: “New machine learning theory raises questions about nature of science.”

Francis Bello

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As we experiment with epistemology, we might send carefully-observed and calculated birthday greetings to Georg Joachim de Porris (better known by his professional name, Rheticus; he was born on this date in 1514. A mathematician, astronomer, cartographer, navigational-instrument maker, medical practitioner, and teacher, he was well-known in his day for his stature in all of those fields. But he is surely best-remembered as the sole pupil of Copernicus, whose work he championed– most impactfully, facilitating the publication of his master’s De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres)… and informing the most famous work by yesterday’s birthday boy, Galileo.

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“Immigrants, we get the job done”*…

When the Piccirilli Brothers arrived in New York from Italy in 1888, they brought with them skill, artistry, and passion for stone-carving unrivaled in the United States. At their studio at 467 East 142nd Street, in the Mott Haven Section of the Bronx, the brothers turned monumental slabs of marble into some of the nation’s recognizable icons, including the senate pediment of the US Capitol Building and the statue of Abraham Lincoln that sits resolutely in the Lincoln Memorial on the National Mall.

The Piccirillis not only helped set our national narrative in stone but they also left an indelible mark on New York City. They carved hundreds of commissions around the five boroughs, including the 11 figures in the pediment of the New York Stock exchange, the “four continents” adorning the Customs House at Bowling Green, the two stately lions that guard the New York Public Library, both statues of George Washington for the Arch at Washington Square, and upwards of 500 individual carvings at Riverside Church…

The remarkable story of a remarkable family: “How six Italian immigrants from the South Bronx carved some of the nation’s most iconic sculptures.” 

* Lin-Manuel Miranda (as Hamilton, to Lafayette in Hamilton)

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As we celebrate sculpture, we might wish a grateful Happy Birthday to another son of Italy, Galileo Galilei, the physicist, mathematician, astronomer, and philosopher who, with Francis Bacon, pioneered the Scientific Method; he was born on this date in 1564.  It was Galileo’s observations that gave conclusive support to Copernicus’ heliocentric theory of the solar system.

Tintoretto’s portrait of Galileo

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“We forced our opponents to change their minds”*…

 

Change

 

There are those who say this pandemic shouldn’t be politicised. That doing so is tantamount to basking in self-righteousness. Like the religious hardliner shouting it’s the wrath of God, or the populist scaremongering about the “Chinese virus”, or the trend-watcher predicting we’re finally entering a new era of love, mindfulness, and free money for all.

There are also those who say now is precisely the time to speak out. That the decisions being made at this moment will have ramifications far into the future. Or, as Obama’s chief of staff put it after Lehman Brothers fell in 2008: “You never want a serious crisis to go to waste.”

In the first few weeks, I tended to side with the naysayers. I’ve written before about the opportunities crises present, but now it seemed tactless, even offensive. Then more days passed. Little by little, it started to dawn that this crisis might last months, a year, even longer. And that anti-crisis measures imposed temporarily one day could well become permanent the next.

No one knows what awaits us this time. But it’s precisely because we don’t know because the future is so uncertain, that we need to talk about it…

In a crisis, what was once unthinkable can suddenly become inevitable. We’re in the middle of the biggest societal shakeup since the second world war…

In a fundamentally optimistic essay, historian Rutger Bregman peers through the Overton Window to explain the seemingly-sudden ripening of ideas that seemed impossible just months ago: “The neoliberal era is ending. What comes next?

See also: “Bruno Latour: ‘This is a global catastrophe that has come from within’.”

And for some (more) historical context, in the form of a scientist’s computer model that tracks “cycles” he has detected in the U.S. since 1780– culminating (so far) in his prediction in Nature in 2010 that 2020 would see huge unrest– see “This Researcher Predicted 2020 Would Be Mayhem. Here’s What He Says May Come Next.”

* Margaret Thatcher in 2002, alluding to Tony Blair and New Labour when asked what she saw as her great achievement.  (N.B., as the piece excerpted above explains, in 2020, Bernie Sanders’s “moderate” rival Joe Biden is proposing tax increases

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As we buckle up, we might recall that it was on this date in 1633 that Galileo delivered his Fourth (and final) Deposition to the court of the Inquisition, which had raised theological objections to his heliocentric view of the solar system (for the second time, he had been tried in 1616 for the same offense, and both censured and censored– his books were banned).  This second trial, occasioned by his publication of Dialogue Concerning the Two Chief World Systems, which resurfaced his heliocentric view, ended the following day, when the Inquisitor issued these rulings:

 

  • Galileo was found “vehemently suspect of heresy”, namely of having held the opinions that the Sun lies motionless at the center of the universe, that the Earth is not at its center and moves, and that one may hold and defend an opinion as probable after it has been declared contrary to Holy Scripture.  He was required to “abjure, curse, and detest” those opinions.
  • He was sentenced to formal imprisonment at the pleasure of the Inquisition.  (On the following day this was commuted to house arrest, under which he remained for the rest of his life.)
  • His offending Dialogue was banned; and in an action not announced at the trial, publication of any of his works was forbidden, including any he might write in the future

300px-Galileo_before_the_Holy_Office

Galileo before the Holy Office, a 19th-century painting by Joseph-Nicolas Robert-Fleury

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Written by LW

June 18, 2020 at 1:01 am

“Memories, you’re talking about memories”*…

 

blade-runner-still-1-

It’s natural, here at the lip of a new year, to wonder what 2019 might hold.  And it’s bracing to note that Blade Runner (released in 1982) is one of 14 films set in a future that is this, the year on which we’re embarking.

But lest we dwell on the dark prognostication they tend to portray, we might take heart from Jill Lepore’s wonderfully-entertaining review of predictions: “What 2018 looked like fifty years ago” and recent honoree Isaac Asimov’s 1983 response to the Toronto Star‘s request for a look at the world of 2019.

Niels Bohr was surely right when he observed that “prediction is difficult, especially about the future.”

* Rick Deckard (Harrison Ford), Blade Runner

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As we contend with the contemporary, we might spend a memorial moment honoring two extraordinary explorers who died on this date.  Marco Polo, whose coda to his remarkable travelogue was “I did not tell half of what I saw,” passed away on this date in 1324.

A page from “Il Milione” (aka” Le Livre des Merveilles” (“The Book of Wonders”)… and in English, “The Travels of Marco Polo”

And Galileo Galilei, the Italian physicist, philosopher, and pioneering astronomer, rose to his beloved heavens on this date in 1642.  Galileo (whom, readers will recall, had his share of trouble with authorities displeased with his challenge to Aristotelean cosmology), died insisting “still, it [the Earth] moves.”

Draft of Galileo’s letter to Leonardo Donato, Doge of Venice, in which he first recorded the movement of the moons of Jupiter– an observation that upset the notion that all celestial bodies must revolve around the Earth.

Written by LW

January 8, 2019 at 1:01 am

“Equipped with his five senses, man explores the universe around him and calls the adventure Science”*…

 

Caleb Scharf wants to take you on an epic tour. His latest book, The Zoomable Universe, starts from the ends of the observable universe, exploring its biggest structures, like groups of galaxies, and goes all the way down to the Planck length—less than a billionth of a billionth of a billionth of a meter. It is a breathtaking synthesis of the large and small. Readers journeying through the book are treated to pictures, diagrams, and illustrations all accompanied by Scharf’s lucid, conversational prose. These visual aids give vital depth and perspective to the phenomena that he points out like a cosmic safari guide. Did you know, he offers, that all the Milky Way’s stars can fit inside the volume of our solar system?

Scharf, the director of Columbia University’s Astrobiology Center, is a suitably engaging guide. He’s the author of the 2012 book Gravity’s Engines: How Bubble-Blowing Black Holes Rule Galaxies, Stars, and Life in the Universe, and last year he speculated in Nautilus about whether alien life could be so advanced as to be indistinguishable from physics.

In The Zoomable Universe, Scharf puts the notion of scale—in biology and physics—center-stage. “The start of your journey through this book and through all known scales of reality is at that edge between known and unknown,” he writes…

Another entry in a collection that long-time readers know your correspondent cultivates, visualizations of relative scale (inspired by Charles and Ray Eames’ Powers of Ten—see, e.g., here, here, here, and here): “This Will Help You Grasp the Sizes of Things in the Universe.”

* Edwin Powell Hubble

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As we keep things in perspective, we might spare a thought for Paolo Frisi; he died on this date in 1784.  A mathematician, astronomer, and physicist who worked in hydraulics (he designed a canal between Milan and Pavia) and introduced the lightning conductor into Italy, he is probably best remembered for his compilation, interpretation, and dissemination of the work of other scientists, especially Galileo Galilei and Sir Isaac Newton.

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Your correspondent is headed into the Thanksgiving Holiday– and so into a brief hiatus in posting.  Regular service will resume on Sunday the 26th… or when the tryptophan haze clears, whichever comes first.

Written by LW

November 22, 2017 at 1:01 am

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