Field of Science

Computer simulations and the Universe

There is a sense in certain quarters that both experimental and theoretical fundamental physics are at an impasse. Other branches of physics like condensed matter physics and fluid dynamics are thriving, but since the composition and existence of the fundamental basis of matter, the origins of the universe and the unity of quantum mechanics with general relativity have long since been held to be foundational matters in physics, this lack of progress rightly bothers its practitioners.
Each of these two aspects of physics faces its own problems. Experimental physics is in trouble because it now relies on energies that cannot be reached even by the biggest particle accelerators around, and building new accelerators will require billions of dollars at a minimum. Even before it was difficult to get this kind of money; in the 1990s the Superconducting Supercollider, an accelerator which would have cost about $2 billion and reached energies greater than those reached by the Large Hadron Collider, was shelved because of a lack of consensus among physicists, political foot dragging and budget concerns. The next particle accelerator which is projected to cost $10 billion is seen as a bad investment by some, especially since previous expensive experiments in physics have confirmed prior theoretical foundations rather than discovered new phenomena or particles.
Fundamental theoretical physics is in trouble because it has become unfalsifiable, divorced from experiment and entangled in mathematical complexities. String theory which was thought to be the most promising approach to unifying quantum mechanics and general relativity has come under particular scrutiny, and its lack of falsifiable predictive power has become so visible that some philosophers have suggested that traditional criteria for a theory’s success like falsification should no longer be applied to string theory. Not surprisingly, many scientists as well as philosophers have frowned on this proposed novel, postmodern model of scientific validation.
Quite aside from specific examples in theory and experiment, perhaps the most serious roadblock that fundamental physics seems to be facing is that it might have reached the end of “Why”. That is to say, the causal framework for explaining phenomena that has been a mainstay of physics since its very beginnings might have ominously hit a wall. For instance, the Large Hadron Collider found the Higgs Boson, but this particle had already been predicted thirty years before. Similarly, the gravitational waves predicted by LIGO were a logical prediction of Einstein’s theory of relativity proposed almost a hundred years before. Both these experiments were technical tour de forces, but they did not make startling, unexpected new discoveries. Other “big physics” experiments before the LHC had validated the predictions of the Standard Model which is our best theoretical framework for the fundamental constituents of matter.
The problem is that the basic fundamental constants in the Standard Model like the masses of elementary particles and their numbers are ad hoc quantities. Nobody knows why they have the values they do. This dilemma has led some physicists to propose the idea that while our universe happens to be the one in which the fundamental constants have certain specific values, there might be other universes in which they have different values. This need for explanation of the values of the fundamental constants is part of the reason why theories of the multiverse are popular. Even if true, this scenario does not bode well for the state of physics. In his collection of essays “The Accidental Universe”, physicist and writer Alan Lightman says:
Dramatic developments in cosmological findings and thought have led some of the world’s premier physicists to propose that our universe is only one of an enormous number of universes, with wildly varying properties, and that some of the most basic features of our particular universe are mere accidents – random throws of the cosmic dice. In which case, there is no hope of ever explaining these features in terms of fundamental causes and principles.
Lightman also quotes the reigning doyen of theoretical physicists, Steven Weinberg, who recognizes this watershed in the history of his discipline:
We now find ourselves at a historic fork in the road we travel to understand the laws of nature. If the multiverse idea is correct, the style of fundamental physics will be radically changed.
Although Weinberg does not say this, what’s depressing about the multiverse is that its existence might always remain postulated and never proven since there is no easy way to experimentally test it. This is a particularly bad scenario because the only thing that a scientist hates even more than an unpleasant answer to a question is no answer at all.
Do the roadblocks that experimental and theoretical physics have hit combined with the lack of explanation of fundamental constants mean that fundamental physics is stuck forever? Perhaps not. Here one must remember Einstein when he said that “Our problems cannot be solved with the same thinking that created them”. Physicists may have to think in wholly different ways, to change the fundamental style that Weinberg refers to, in order to overcome the impasse.
Fortunately there is one tool in addition to theory and experiment which has not been prominently used by physicists but which has been used by biologists and chemists and which could help physicists do new experiments. That tool is computation. Computation is usually regarded separately from experiment, but computational experiments can be performed the same way that lab experiments can as long as the parameters and models underlying the computation are well defined and valid.  In the last few decades, computation has become as legitimate a tool in science as theory and experiment.
Interestingly, this problem of trying to explain fundamental phenomena without being able to resort to deeper explanations is familiar to biologists: it is the old problem of contingency and chance in evolution. Just like physicists want to explain why the proton has a certain mass, biologists want to explain why marsupials have pouches that carry their young or why Blue Morpho butterflies are a beautiful blue. While proximal explanations for such phenomena are available, the ultimate explanations hinge on chance. Biological evolution could have followed an infinite number of pathways, and the ones that it did simply arose from natural selection acting on random mutations. Similarly one can postulate that while the fundamental constants could have had different values, the ones that they do have in our universe came about simply because of random perturbations, each one of which rendered a different universe. Physics turns into biology.
Is there a way to test this kind of thinking in the absence of concrete experiments? One way would be to think of different universes as different local minima in a multidimensional landscape. This scenario would be familiar  to biochemists who are used to thinking of different folded structures for a protein as lying in different local energy minima. A few years back a biophysicist named Collin Stultz in fact made this comparison as a helpful way to think about the multiverse. Computational biophysicists test this protein landscape by running computer simulations in which they allow an unfolded protein to explore all these different local minima until it finds a global minimum which corresponds to its true folded state. In the last few years, thanks to growing computing power, thousands of such proteins have been simulated.
Similarly, I postulate that computational physicists could perform simulations in which they simulate universes with different values for the fundamental constants and evaluate which ones resemble our real universe. Because the values of the fundamental constants dictate chemistry and biology, one could well imagine completely fantastic physics, biology and chemistry arising in universes with different values for Planck’s constant or for the fine structure constant. A 0.001% difference in some values might lead to a lifeless universe with total silence, one with only black holes or spectacularly exploding supernovae, or one which bounced back between infinitesimal and infinite length scales in a split second. Smaller variations on the constants could result in a universe with silicon-based life, or one with liquid ammonia rather than water as life’s essential solvent, or one with a few million earth-like planets in every galaxy. With a slight tweaking of the cosmic calculator, one could even have universes where Blue Morpho butterflies are the dominant intelligent species or where humans have the capacity to photosynthesize.
All these alternative universes could be simulated and explored by computational physicists without the need to conduct billion dollar experiments and deal with politicians for funding. I believe that both the technology and the knowledge base required to simulate entire universes on a computer could be well within our means in the next fifty years, and certainly within the next hundred years. In some sense the technology is already within reach; already we can perform climate and protein structure simulations on mere desktop computers, so simulating whole universes should be possible on supercomputers or distributed cloud computing systems. Crowdsourcing of the kind done for the search for extraterrestrial intelligence or protein folding would be readily feasible. Another alternative would be to do computation using DNA or quantum computers: Because of DNA’s high storage and permutation capacity, computation using DNA can multiply required computational resources manyfold. One can also imagine taking advantage of natural phenomena like electrical discharges in interstellar space or in the clouds of Venus or Jupiter to perform large-scale computation; in fact an intelligence based on communication using electrical discharges was the basis of Fred Hoyle’s science fiction story “The Black Cloud”.
On the theoretical side, the trick is to have enough knowledge about fundamental phenomena and to be able to abstract away the details so that the simulation can be run at the right emergent level. For instance, physicists can already simulate the behavior of entire galaxies and supernovae without worrying about the behavior of every single subatomic particle in the system. Similarly, biologists can simulate the large-scale behavior of ecosystems without worrying about the behavior of every single organism in them. In fact physicists are already quite familiar with such an approach in the field of statistical mechanics where they can simulate quantities like temperature and pressure in a system without simulating every individual atom or molecule in it. And they have measured the values of the fundamental constants to many decimal places to use them confidently in the simulations.
In our hypothetical simulated universe, all the simulator would have to do would be to input slightly different values of the fundamental constants and then hard-code some fundamental emergent laws like evolution by natural selection and the laws of chemical bonding. In fact, a particularly entertaining enterprise would be to run the simulation and see if these laws emerge by themselves. The whole simulation would in one sense largely be a matter of adjusting initial values, setting the boundary value conditions and then sitting back and watching the ensuing fireworks. It would simply be an extension of what scientists already do using computers albeit on a much larger scale. Once the simulations are validated, they could be turned into user-friendly tools or toys that can be used by children. The children could try to simulate their own universes and can have contests to see which one creates the most interesting physics, chemistry and biology. Adults as well as children could thus participate in extending the boundaries of our knowledge of fundamental physics.
Large-scale simulation of multiple universes can help break the impasse that both experimentation and theory in fundamental physics are facing. Computation cannot completely replace experiment if the underlying parameters and assumptions are not well-validated, but there is no reason why this cannot happen as our knowledge of the world based on small-scale experiments grows. In fields like theoretical chemistry, weather prediction and drug development, computational predictions are becoming as important as experimental tests. At the very least, the results from these computational studies will constrain the number of potential experimental tests and provide more confidence in asking governments to allocate billions of dollars for the next generation of particle accelerators and gravitational wave detectors.
I believe that the ability to simulate entire universes is imminent, will be part of the future of physics and will undoubtedly lead to many exciting results. But the most exciting ones will be those that even our best science fiction writers cannot imagine. That is something we can truly look forward to.

First published on 3 Quarks Daily.

Book review: Roger Williams and the Creation of the American Soul

Roger Williams and the Creation of the American Soul: Church, State, and the Birth of LibertyRoger Williams and the Creation of the American Soul: Church, State, and the Birth of Liberty by John M. Barry

If anyone wants to know what makes the United States unique, part of the answer can be found in this book. At its center is a wholly remarkable, extraordinary, awe-inspiring individual who was light years ahead of his time. Roger Williams founded Rhode Island (then Providence Plantation) in 1636 and it became the world's first model of both full religious tolerance as well as individual rights, and it established government by the consent of the governed as a foundational principle. At that time nothing like it existed anywhere, and certainly not in Europe where Catholics and Protestants were killing each other over absurdly trivial matters like the age for baptism and Calvinist predestination. Williams's teachings and writings set the stage for fundamental debates about the role of religion and the state in individuals' lives with which we are still grappling.

Williams had fled from England when Charles I intensified his father James I's campaign to persecute Protestant Puritans who wanted a purer, more rigorous form of worship. Growing up in London, Williams had been enormously influenced by Edward Coke and Francis Bacon, two men who ironically were sworn enemies. Coke was the most eminent jurist in English history and had challenged the divine right of kings and emphasized rights to property and due process. Bacon was one of the fathers of the scientific method and put a premium on evidence and observation. From both these men Williams imbibed a deep set of ethics about free, secular thinking.

He arrived in Massachusetts a decade after the Mayflower docked at Plymouth and a few years after the Massachusetts Bay Colony was established by John Winthrop, the "city on a hill". A talented lawyer, minister and linguist who was steeped in Bacon's scientific method, he became friends with the Indians, learnt their customs and and became fluent in their language. He was received with great respect and offered the post of minister in the newly-established Boston's first church. His time in history came when he made a historic break by opposing two basic tenets of the Puritans and Christians in general: that the state should have no authority to enforce the first four commandments dealing with God, and that Indians had property rights too and the Puritans did not have the authority to simply seize them and needed to buy their lands. This went not just against the fundamentalist religious beliefs of the colony but was something wholly new that directly contradicted both the meld between church and state and in fact all the political and religious philosophy that existed at the time.

For his novel views Williams was duly banished from Massachusetts under threat of execution, but he kept on privately preaching his creed in the more tolerant Salem. When Massachusetts sent out a squad of soldiers to haul him onto a ship bound for England for imprisonment, they found that (goaded by a tip from Winthrop), Williams had already escaped into the bitter, snowy winter wilderness. The only reason he remained alive was because he found refuge and friendship among the Narragansett and other Indians who lived in the area, and the fact that his friends and colleagues had denounced him while strangers had saved his life fundamentally changed his views of race, of religion, of Native Americans, of freedom and individual rights, of how much control men should have over other men. His colony became a refuge for the rejected, the denounced, the banished of Massachusetts, Plymouth and Connecticut; the three major colonies of the time.

He decided to codify his beliefs in a formal document. Massachusetts kept on being threatened by its freethinking neighbor to the South and kept on trying to usurp its territories, so Williams went back again to the same England from which he had fled about fifteen years ago. At this point England itself had become roiled up in what was going to lead to the English Civil War and the execution of Charles I. He befriended Oliver Cromwell and managed to get a charter for Rhode Island written and later endorsed by Charles II (who seems to have forgiven his friendship with Cromwell). In an age when almost every piece of paper including the founding charter of Puritan Massachusetts was infused throughout with the names of God and Christ, the Rhode Island charter is an extraordinary document, not mentioning God even once. It established almost complete freedom of religion and made it clear that no one should be persecuted simply for their beliefs; a groundbreaking assertion at a time when even minor differences in religious beliefs between Catholics and Protestants, let alone ones between Protestants and Jews or Quakers, were enough to ignite religious wars that killed thousands. Finally, with his charter safely establishing the legality of Rhode Island, Williams returned back to his colony and lived to be an old man, still preaching the gospel of tolerance.

Williams's writing serve as the foundation for the novelty of the American experiment. He was a devout Christian who conceived a separation of church from state, private from public activity. He might have been the first bonafide libertarian. There is a straight line between his teachings, John Locke, the Declaration of Independence and all the worldwide events that the American Revolution inspired. No wonder that when the tide of history met the shores of fate, not only did Rhode Island become the first to protest against unlawful behavior by the English even before the Boston Tea Party, but it became the first state in the colonies to declare independence from Great Britain in 1776.

Book review: Fur, Fortune and Empire

Fur, Fortune, and Empire: The Epic History of the Fur Trade in AmericaFur, Fortune, and Empire: The Epic History of the Fur Trade in America by Eric Jay Dolin

A marvelous and highly revealing history of the fur trade in America, right from the first permanent European settlements in the 17th century to the end of the 19th century. A story of inspiring doggedness against an incredibly unforgiving environment and of the tragic clash of civilizations.

Dolin's basic thesis is that fur was to the 17th and 19th centuries what oil was to the 20th, and it was the possibility of buying beaver furs in unprecedented quantities for fashion-hungry Europe from Indians that largely drew first the Dutch and French and later the English to North America, so the settling and expansion of North America especially to the West tracks very closely with the fur trade. Having access to the Mississippi and the Hudson rivers, the former were much better placed to buy fur in exchange for European goods, at first trinkets like utensils and clothing but later deadlier commodities like guns and alcohol. The Dutch started trading for beaver pelts in their New Amsterdam colony, while the French swept in from Canada and controlled the Mississippi. This led to an inevitable clash between the British and the French for control of the Great Lakes region. After the French and Indian War, clashes arose between the British and the colonies regarding jurisdiction over the newly-opened vast Ohio territory and its lucrative fur possibilities, and this was at least one of the factors leading to the American Revolution. Americans continued to duke it out with the British even as both expanded into the Northwest, this time killing sea otters in unprecedented numbers for trade with China with brutal techniques and gleeful avarice. The Lewis and Clark expedition was at least in part a quest to map lucrative locations for the fur trade.

One of the highlights of the book is the light it sheds on early European-Indian relations which were much more benign compared to later years. In almost every case the Indians welcomed the Europeans at first contact and were in awe of their guns and other modern technology. Partly out of necessity - the Europeans were completely dependent on the natives at first for fetching furs from the deep interior - and partly out of genuine respect and curiosity, Europeans established trading relationships with the Indians through trading posts, and the Indians were often canny enough to play competing French and British trappers and companies against each other to get the best price. The relationship started changing when the Europeans became more land-hungry and when they started taking advantage of the Indians by plying them with alcohol; the independent forays of European trappers also started reducing their dependence on native fur acquisition. But there were violent clashes on both sides, sometimes instigated by Indians but more often invoked by European greed.

The book has memorable portraits of key fur trappers, sailors and soldiers who braved unbelievable rigors of starvation, predation and hostile engagements with Indians to get the furs, living for months in inhospitable, sub-zero temperatures in the Midwest and the Great Plains. One of these "mountain men" was Hugo Glass who was mauled by a grizzly bear and left for dead before he endured an astonishing foot journey to reach civilization; Glass was the inspiration for the movie "The Revenant". The mountain men are fascinating; mostly originating from Kentucky, Tennessee and other border states, they were the most free-lancing among the free-lancing trappers, traveling with aplomb whenever and wherever they wanted, yet 80% of them were married and a third took Indian wives. What is truly interesting is that these uneducated, hardy men were often as well read as an East Coast businessman and practiced a kind of equality among themselves and their wives, often living in communal camps, that might have been unique on the continent for the times. Other memorable characters include John Jacob Astor, one of America's first millionaires who thrived on and greatly expanded the fur trade, Captain James Cook who was the first to discover the Northwest before he was killed in Hawaii and frontiersmen like Kit Carson, Daniel Boone and Manuel Lisa.

The last part of the book deals with the tragic effects the fur trade had on America's fauna as well as on the Indians. By the 1850s or so Europeans and Indians had both hunted the beaver nearly to extinction before they discovered a new source of fur: the American buffalo or bison. With that discovery began probably the greatest episode of manmade carnage in history. At the beginning tens of millions of buffalo roamed the Great Plains and the Southwest; by the end of 1890 there were a few hundred. The building of the transcontinental railroad sealed the fate of both the buffalo and the Indians in whose life the buffalo was so intimately integrated that they would use and consume every single part of it, including the scrotum and the tail, the heart and the blood. Meanwhile, Europeans started killing the animal for sport, sometimes lazily shooting it from train compartments and leaving the carcasses rotting. The long-range rifle made it possible for a single hunter to kill dozens in a day and waste most of their meat. Soon the plains were literally dotted with rotting carcasses and skulls for as far as the eye could see. The westward expansion also split the Indian population into small groups which were at the mercy of settlers and the U.S. Army, leading to their complete subjugation. This was truly a sad chapter in the history of the United States, and one that frankly brought tears to my eyes.

Not just the buffalo but the beaver and the sea otter were killed in the tens of millions and hunted to near extinction, so it's perhaps a miracle that they are still around. While the history of the fur trade tells the story of expansion, greed, killings and conquest along with one of resilience, doggedness and adventure, its aftermath tells a story of hope even as Teddy Roosevelt, John Muir, Thoreau and others reminded Americans of humans' deep connection to nature, made a strong push for conservation and assigned large areas of the country to conservation where bison, otters and other animals killed during the fur trade started thriving again. A few years ago a beaver was spotted on the Bronx River in New York for the first time in two hundred years. Perhaps there is a kernel of compassion and hope in the gnarly undergrowth of man's cruelty after all.

Book review: Miracle at Philadelphia

Miracle at Philadelphia: The Story of the Constitutional Convention, May to September 1787Miracle at Philadelphia: The Story of the Constitutional Convention, May to September 1787 by Catherine Drinker Bowen

A superb, must-read day-by-day account of the Constitutional Convention which took place in Philadelphia between May and September 1787. The writing and description of not just the deliberations and the personalities but the stuffy, hot, Philadelphia weather, the shops, the clothes and the impressions of European visitors of a society that snubs its nose at class are so vivid that you get the feeling you are there. I have read a few other accounts of this all-important episode, but none so revealing as to the spirit of the times.

Present here are the great men of American history in all their glory and flaws: Washington, Hamilton, Madison, Franklin, Gouverneur Morris (from whose pen came “We the people” in the preamble to the Constitution), and even a lobbyist for land companies, Manasseh Cutler, who helped draft the Northwest Ordinance that created the vast Northwest Territory and sealed the fate of millions of Indians. Exerting their influence subtly from Europe were Jefferson and Adams. There were fiery speakers both for and against a central government - George Mason and Edmund Randolph from Virginia, Luther Martin from Maryland, Hamilton from New York, Elbridge Gerry from Massachusetts (from whom comes one of my favorite quotes: “The evils we have stem from the excess of democracy. The people do not want virtue, but are the dupes of pretended patriots”) - who made no secret of their feelings. They formed the Federalists and Antifederalists who were to have such bitter debates later.

Discussed were issues both trivial and momentous: the exact terms for Senators and Congressmen, whether the President should be appointed for life, the regulation of trade with other countries, the requirements for voting and citizenship, the provision for a national army. But the three most important issues were taxation, representation in both houses, and Western expansion. In many ways these issues encapsulated the central issue: states’ rights vs a strong national government. The small states were afraid that proportional representation would diminish their influence to nothing; the large ones were afraid that incomplete representation would harm their economy, their manufacturing and their landed gentry; sparsely populated ones worried that it would harm Westward expansion and slavery. Many people spoke openly against slavery, but it was out of concerns for the Southern states’ objections that the Constitution adopted the infamous three-fifths clause relating to “other persons” (there was consolation in the fact that the convention at least set a 1808 date for the ending of the slave trade). To soothe concerns on both sides, Roger Sherman of Connecticut offered the Sherman Compromise which proposed that the House would have proportionate representation while the Senate’s composition would be fixed to two from each state.

Women, white men without property, Africans and Indians famously got fleeced. As Jill Lepore wrote in her history “These Truths”, while Africans were degraded as slaves and considered as three-fifths of men, women fared almost as badly and were completely left out of the Constitution: in 1776, Abigail Adams memorably wrote to her husband, "Do not put such unlimited power into the hands of the husbands. Remember, all men would be tyrants if they could. If particular care and attention is not paid to the ladies, we are determined to foment a rebellion, and will not hold ourselves bound by any laws in which we have no voice or representation”, but her words were far from anyone’s mind in 1787. Women’s rights as we know them were non-existent then. But the Constitution was at least a triumph of religious freedom when, in the face of objections by some prominent Americans, it did away with any religious test for becoming a citizen and for holding office. This was a revolutionary move for the times.

Bowen’s book also does a fantastic job of letting us see the world through the eyes of these men and women. It’s very difficult for us in the age of the Internet to realize how slow communication was during those times and how disconnected people felt from each other in the unimaginably vast expanse of the country and the frontier to the West. The states were so loosely bound to each other by the previous Articles of Confederation and had such disparate geographies and cultures that in some cases they were threatening to fracture (for instance Maine wanted to separate from Massachusetts, and Virginia was planning to form a navy to defend herself against other states) So many of the concerns arose from legitimate worries that a Senator or President from Washington would never understand the concerns of a farmer from South Carolina, or that a farmer from South Carolina would never understand the concerns of a New England artisan. The fear that a central government would run roughshod over individual states was a very real one, although seventy years later it manifested itself in an ugly incarnation. There was also deep skepticism about “the people” (as Hamilton had put it, “If men were angels, governments would be unnecessary.”), and many vociferously asked that the preamble should say “We the states”.

Another revealing aspect of the book is to communicate how many measures were either defeated when they were first proposed or passed by a slim majority; sometimes the delegates even changed their votes. This was democracy in action; giving everyone a chance to voice their concerns while still obeying the wishes of the majority. Fun fact, especially in light of the present times: the presidential veto was struck down ten-to-one when first proposed. And, in what today seems like the most incomprehensible move, a Bill of Rights was also struck down ten-to-one when first proposed. The main argument was: if Americans are already free, why do they need a separate Bill of Rights? And if you are already laying down rules for what the government can do, why is it necessary to explicitly state what it cannot do? It was only after the Constitution was sent to the states for ratification that Massachusetts proposed adding a bill of rights; in fact some of the amendments in the Bill or Rights mirror Massachusetts’ own proposals for a state bill of rights. Once the powerful states like Massachusetts, Virginia and Pennsylvania ratified, the other states quickly fell in line.

It is wonderful to see Antifederalists who had opposed the Constitution immediately concede to the wishes of the people, often in generous terms, when it is ratified by individual states. In fact that is perhaps the single-most important fact that comes across in Bowen’s account; that men with widely differing views reached a compromise and forged a document which, although it contained important flaws, became a trailblazing, unique, enduring piece of work asking for a “more perfect Union” that led to a clarion call for individual rights and liberty not just in the United States but throughout the world.

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