Brains, Computation And Thermodynamics: A View From The Future?

Rolf Landauer
Progress in science often happens when two or more fields productively meet. Astrophysics got a huge boost when the tools of radio and radar met the age-old science of astronomy. From this fruitful marriage came things like the discovery of the radiation from the big bang. Another example was the union of biology with chemistry and quantum mechanics that gave rise to molecular biology. There is little doubt that some of the most important future discoveries in science in the future will similarly arise from the accidental fusion of multiple disciplines.
One such fusion sits on the horizon, largely underappreciated and unseen by the public. It is the fusion between physics, computer science and biology. More specifically, this fusion will likely see its greatest manifestation in the interplay between information theory, thermodynamics and neuroscience. My prediction is that this fusion will be every bit as important as any potential fusion of general relativity with quantum theory, and at least as important as the development of molecular biology in the mid 20th century. I also believe that this development will likely happen during my own lifetime.
The roots of this predicted marriage go back to 1867. In that year the great Scottish physicist James Clerk Maxwell proposed a thought experiment that was later called ‘Maxwell’s Demon’. Maxwell’s Demon was purportedly a way to defy the second law of thermodynamics that had been proposed a few years earlier. The second law of thermodynamics is one of the fundamental laws governing everything in the universe, from the birth of stars to the birth of babies. It basically states that left to itself, an isolated system will tend to go from a state of order to one of disorder. A good example is how a bottle of perfume wafts throughout a room with time. This order and disorder was quantified by a quantity called entropy.
In technical terms, the order and disorder refers to the number of states a system can exist in; order means fewer states and disorder means more. The second law states that isolated systems will always go from fewer states and lower entropy (order) to more states and higher entropy (disorder). Ludwig Boltzmann quantified this relationship with a simple equation carved on his tombstone in Vienna: S = klnW, where k is a constant called the Boltzmann constant, ln is the natural logarithm (to the base e) and W is the number of states.
Maxwell’s Demon was a mischievous creature which sat on top of a box with a partition in the middle. The box contains molecules of a gas which are ricocheting in every direction. Maxwell himself had found that these molecules’ velocities follow a particular distribution of fast and slow. The demon observes these velocities, and whenever there is a molecule moving faster than usual in the right side of the box, he opens the partition and lets it into the left side, quickly closing the partition. Similarly he lets in slower moving molecules from left to right. After some time, all the slow molecules will be in the right side and the fast ones will in the left. Now, velocity is related to temperature, so this means that one side of the box has heated up and the other has cooled down. To put it another way, the box went from a state of random disorder to order. According to the second law this means that the entropy of the system of the system decreased, which is impossible.
Maxwell’s demon seemingly contravenes the second law of thermodynamics (University of Pittsburgh)
For the next few years scientists tried to get around Maxwell’s Demon’s paradox, but it was in 1922 that the Hungarian physicist Leo Szilard made a dent in it when he was a graduate student hobnobbing with Einstein, Planck and other physicists in Berlin. Szilard realized an obvious truth that many others seem to have missed. The work and decision-making that the demon does to determine the velocities of the molecules itself generates entropy. If one takes this work into account, it turns out that the total entropy of the system has indeed increased. The second law is safe. Szilard later went on to a distinguished career as a nuclear physicist, patenting a refrigerator with Einstein and becoming the first person to think of a chain reaction.
Perhaps unknowingly, however, Szilard had also discovered a connection – a fusion of two fields – that was going to revolutionize both science and technology. When the demon does work to determine the velocities of molecules, the entropy that he creates comes not just from the raising and lowering of the partition but from his thinking processes, and these processes involve information processing. Szilard had discovered a crucial and tantalizing link between entropy and information. Two decades later, mathematician Claude Shannon was working at Bell Labs, trying to improve the communication of signals through wires. This was unsurprisingly an important problem for a telephone and communications company. The problem was that when engineers were trying to send a message over a wire, it would lose its quality because of many factors including noise. One of Shannon’s jobs was to figure out how to make this transmission more efficient.
Shannon found out that there is a quantity that relates to the information transmitted over the wire. In crude terms, this quantity was inversely related to the information as well as to the probability of transmitting that information; the higher the probability of transmitting accurate information over a channel, the lower this quantity was and vice versa. When Shannon showed his result to the famous mathematician John von Neumann, von Neumann with his well-known lightning-fast ability to connect disparate ideas, immediately saw what it was: “You should call your function ‘entropy’”, he said, “firstly because that is what it looks like in thermodynamics, and secondly because nobody really knows what entropy is, so in a debate you will always have the upper hand.” Thus was born the connection between information and entropy. Another fortuitous connection was born – between information, entropy and error or uncertainty. The greater the uncertainty in transmitting a message, the greater the entropy, so entropy also provided a way to quantify error. Shannon’s 1948 paper, “A Mathematical Theory of Communication”, was a seminal publication and has been called the Magna Carta of the information age.
Even before Shannon, another pioneer had published a paper that laid the foundations of the theory of computing. In 1936 Alan Turing published “On Computable Numbers, with an Application to the Entscheidungsproblem”. This paper introduced the concept of Turing machines which also process information. But neither Turing nor von Neumann really made the connection between computation, entropy and information explicit. Making it explicit would take another few decades. But during those decades, another fascinating connection between thermodynamics and information would be discovered.
Stephen Hawking’s tombstone at Westminster Abbey (Cambridge News)
That connection came from Stephen Hawking getting annoyed. Hawking was one of the pioneers of black holes, and along with Roger Penrose he had discovered that at the center of every black hole is a singularity that warps spacetime infinitely. The boundary of the black hole is its event horizon and within that boundary not even light can escape. But black holes posed some fundamental problems for thermodynamics. Every object contains entropy, so when an object disappears into a black hole, where does its entropy go? If the entropy of the black hole does not increase then the second law of thermodynamics would be violated. Hawking had proven that the area of a black hole’s event horizon never decreases, but he had pushed the thermodynamic question under the rug. In 1972 at a physics summer school, Hawking met a graduate student from Princeton named Jacob Bekenstein who proposed that the increasing area of the black hole was basically a proxy for its increasing entropy. This annoyed Hawking and he did not believe it because increased entropy is related to heat (heat is the highest- entropy form of energy) and black holes, being black, could not radiate heat. With two colleagues Hawking set out to prove Bekenstein wrong. In the process, he not only proved him right but also made what is considered his greatest breakthrough: he gave black holes a temperature. Hawking found out that black holes do emit thermal radiation. This radiation can be explained when you take quantum mechanics into account. The Hawking-Bekenstein discovery was a spectacular example of another fusion: between information, thermodynamics, quantum mechanics and general relativity. Hawking deemed it so important that he wanted to put it on his tombstone in Westminster Abbey, and so it has been.
This short digression was to show that more links between information, thermodynamics and other disciplines were being forged in the 1960s and 70s. But nobody saw the connections between computation and thermodynamics until Rolf Landauer and Charles Bennett came along. Bennett and Landauer were both working at IBM. Landauer was an √©migr√© who fled from Nazi Germany before working for the US Navy as an electrician’s mate, getting his PhD at Harvard and joining IBM. IBM was then a pioneer of computing; among other things they had built computers for the Manhattan Project. In 1961, Landauer published a paper titled “Irreversibility and Heat Generation in the Computing Process” that is destined to become a classic of science. In it, Landauer established that the basic act of computation – the change of one bit to another, say a 1 to a 0 – requires a bare minimum amount of entropy. He quantified this amount with another simple equation: S = kln2, with k again being the Boltzmann constant and ln the natural logarithm. This has become known as the Landauer bound; it is the absolute minimum amount of entropy that has to be expended in a single bit operation. Landauer died in 1999 and as far as I know the equation is not carved on his tombstone.
The Landauer bound applies to all kinds of computation in principle and biological processes are also a form of information processing and computation, so it’s tantalizing to ask whether Landauer’s calculation applies to them. Enter Charles Bennett. Bennett is one of the most famous scientists whose name you may not have heard of. He is not only one of the fathers of quantum computing and quantum cryptography but he is also one of the two fathers of the marriage of thermodynamics with computation, Landauer being the other. Working with Landauer in the 1970s and 80s, Bennett applied thermodynamics to both Turing machines and biology. By good fortune he had gotten his PhD in physical chemistry studying the motion of molecules, so his background primed him to apply ideas from computation to biology.
Charles Bennett from IBM has revolutionized our understanding of the thermodynamics of computation (AMSS)
To simplify matters, Bennett considered what he called a Brownian Turing machine. Brownian motion is the random motion of atoms and molecules. A Brownian Turing machine can write and erase characters on a tape using energy extracted from a random environment. This makes the Brownian Turing machine reversible. A reversible process might seem strange, but in fact it’s found in biology all the time. Enzyme reactions occur from the reversible motion of chemicals – at equilibrium there is equal probability that an enzymatic reaction will go forward or backward. What makes these processes irreversible is the addition of starting materials or the elimination of chemical products. Even in computation, only a process which erases bits is truly irreversible because you lose information. Bennett envisaged a biological process like protein translation as a Brownian Turing machine which adds or subtracts a molecule like an amino acid, and he calculated the energy and entropy expenditures involved in running this machine. Visualizing translation as a Turing machine made it easier to do a head-to-head comparison between biological processes and bit operations. Bennett found out that if the process is reversible the Landauer bound does not hold and there is no minimum entropy required. Real life of course is irreversible, so how do real-life processes compare to the Landauer bound?
In 2017, a group of researchers published a fascinating paper in the Philosophical Transactions of the Royal Society in which they explicitly calculated the thermodynamic efficiency of biological processes. Remarkably, they found that the efficiency of protein translation is several orders of magnitude better than the best supercomputers, in some cases as better as a million fold. More remarkably, they found that the efficiency is only one order of magnitude worse than the theoretical minimum Landauer bound. In other words, evolution has done one hell of a job in optimizing the thermodynamic efficiency of biological processes.
But not all biological processes. Circling back to the thinking processes of Maxwell’s little demon, how does this efficiency compare to the efficiency of the human brain? Surprisingly, it turns out that neural processes like the firing of synapses are estimated to be much worse than protein translation and more comparable to the efficiency of supercomputers. At first glance, the human brain thus appears to be worse than other biological processes. However, this seemingly low computational efficiency of the brain must be compared to its complex structure and function. The brain weighs only about a fiftieth of the weight of an average human but it uses up 20% of the body’s energy. It might seem that we are simply not getting the biggest bang for our buck, with an energy-hungry brain providing low computational efficiency. What would explain this inefficiency and this paradox?
My guess is that the brain has been designed to be inefficient through a combination of evolutionary accident and design and that efficiency is the wrong metric for gauging the performance of the brain. Efficiency is the wrong metric because thinking of the brain in digital terms is the wrong metric. The brain arose through a series of modular inventions responding to new environments created by both biology and culture. We now know that thriving in these environments needed a combination of analog and digital functions.; for instance, the nerve impulses controlling blood pressure are digital while the actual change in pressure is continuous and analog. It is likely that digital neuronal firing is built on an analog substrate of wet matter, and that higher-order analog functions could be emergent forms of digital neuronal firing. As early as the 1950s, von Neumann conjectured that we would need to model the brain as both analog and digital in order to understand it. Around the time that Bennett was working out the thermodynamics of computation, two mathematicians named Marian Pour-El and Ian Richards proved a very interesting theorem which showed that in certain cases, there are numbers that are not computable with digital computers but are computable with analog processes; analog computers are thus more powerful in such cases.
If our brains are a combination of digital and analog, it’s very likely that they are this way so that they can span a much bigger range of computation. But this bigger range would come at the expense of inefficiency in the analog computation process. The small price of lower computational efficiency as measured by the Landauer bound would come at the expense of the much greater evolutionary benefits of performing complex calculations that allow us to farm, build cities, know stranger from kin and develop technology. Essentially, the Landauer bound could be evidence for the analog nature of our brains. There is another interesting fact about analog computation, which is its greater error rate; digital computers took off precisely because they had low error rates. How does the brain function so well in spite of this relatively high error rate? Is the brain consolidating this error when we dream? And can we reduce this error rate by improving the brain’s efficiency? Would that make our brains better or worse at grasping the world?
From the origins of thermodynamics and Maxwell’s Demon to the fusion of thermodynamics with information processing, black holes, computation and biology, we have come a long way. The fusion of thermodynamics and computation with neuroscience just seems to be beginning, so for a young person starting out in the field the possibilities are exciting and limitless. A multitude of general questions abound: How does the efficiency of the brain relate to its computational abilities? What might be the evolutionary origins of such abilities? What analogies between the processing of information in our memories and that in computers might we discover through this analysis? And finally, just like Shannon did for information, Hawking and Bekenstein did for black holes and Landauer and Bennett did for computation and biology, can we find out a simple equation describing how the entropy of thought processes relates to simple neural parameters connected to memory, thinking, empathy and emotion? I do not know the answers to these questions, but I am hoping someone who is reading this will, and at the very least they will then be able to immortalize themselves by putting another simple formula describing the secrets of the universe on their tombstone.
Further reading:
  1. Charles Bennett – The Thermodynamics of Computation
  2. Seth Lloyd – Ultimate Physical Limits to Computation
  3. Freeman Dyson – Are brains analog or digital?
  4. George Dyson – Analogia: The Emergence of Technology Beyond Programmable Control (August 2020)
  5. Richard Feynman – The Feynman Lectures on Computation (Chapter 5)
  6. John von Neumann – The General and Logical Theory of Automata
First published on 3 Quarks Daily

    On free speech, crossing the Rubicon and the need to unite

    I woke up to some welcome news today, news that after an extended period of disappointment and disillusionment, has left me feeling better than I have in a long time. Harper’s Weekly published an open letter signed by an eclectic blend of writers, political scientists, journalists and thinkers across the political spectrum, many of whom have been pillars of the liberal intellectual community for decades. In the letter, Noam Chomsky, Margaret Atwood, Salman Rushdie, Steven Pinker, Nicholas Christakis, Fareed Zakaria, Arlie Russell Hochschild and many others deplore the state in which liberal discourse has descended into for several years.

    "The free exchange of information and ideas, the lifeblood of a liberal society, is daily becoming more constricted. While we have come to expect this on the radical right, censoriousness is also spreading more widely in our culture: an intolerance of opposing views, a vogue for public shaming and ostracism, and the tendency to dissolve complex policy issues in a blinding moral certainty." 

    The entire letter is worth reading and takes aim at several acts by self-described liberals and Democrats over the years that have been attacks on the values of free expression and debate that they professed to have stood up for for decades. It takes to task institutions which are dealing out disproportionate punishments for minor infractions, if one can call them that. It makes the seemingly obvious case that writers can only thrive when they are allowed to experiment and say controversial things – a whole string of historical writers ranging from Virginia Woolf and D. H Lawrence to Nabokov and Franzen attest to this fact. Rushdie himself of course infamously had to go into hiding for several years after the fatwah. The writers of the letter cite dozens of cases of controversial speakers being disinvited from college campuses, professors being censured for citing “controversial” books like Greek classics, editorials being withdrawn from leading newspapers because of internal rebellion and people’s livelihoods and reputations being threatened for simply tweeting about or referring to something that their detractors disliked. In most cases there was a small group of outraged people, usually on Twitter, responsible for these actions.

    Most of this of course has been going on for years, even as those of us who believed in free speech without retaliation and diversity of viewpoints have watched with increasing dismay from the sidelines. Some of us have even been targets in the past, although we have not had to face the kind of retribution that other people did. And yet, compared to what has been happening this year, the last few years have seemed tame. I have to say that as much as my disillusionment has grown steadily over time, this year truly seems like the watershed, one that should squarely force us to take a stand.

    Let’s first understand that America in 2020 has made everyone’s job difficult: the country is now being led by a racist, ignorant child-president with dictatorial aspirations who calls the press the enemy of the people and whose minions take every chance they can to try to silence or threaten anyone who disagrees with them, who actively spread misinformation and lies, whose understanding of science and reason is non-existent, and who have been collectively responsible not just for the dismantling of critical public institutions like the EPA and the justice department but for orchestrating, through inaction, one of the deadliest public health crises in the history of the country that has killed hundreds of thousands. One would think that all of us who are opposed to this administration and their abandonment of the fundamental values on which this country has been founded would be utterly horrified and unified at this time.

    Sadly, the opposite has happened, and it’s why the Harper’s letter seems like a bright pinprick in a dark landscape to me. For an increasing portion of the self-professed liberal establishment, the answer to Trump has been to go crazy in the other direction. Until this year, I generally used to reject the slippery slope argument – the argument that those even with whom I strongly disagreed will keep on going down a slippery slope. I thought that that would stop at a reasonable juncture. Sadly, I no longer think that way. Three examples among many will suffice, and I think all three are emblematic of larger trends:

    First: After the horrific murder of George Floyd, while we were standing in solidarity with the black community and condemning the use of excessive force by police departments across the country, peaceful protests across the country turned into violent demonstrations accompanied by looting. Now most of the protestors were peaceful, so I thought that my fellow liberals would cleanly draw a line and denounce the looters while supporting the protests. But this seldom happened; both on my private social media accounts as well as publicly, people started excusing the looting as a justified act of desperation. Worse still, they started to recruit cherry-picked historical examples of civil rights leaders to make their case, including this speech by MLK Jr. in which he seems to justify violence as a desperate act before making it very clear that it is not the right way of going about things. But even if you hadn’t heard the entire speech, to hold someone who is literally the biggest symbol of non-violent protests in modern times along with Mahatma Gandhi as a spokesperson for violent protests is bizarre to say the least. 

    The ahistorical anomalies continued. One of my favorites was a tweet by Charles Blow of the New York Times who justified the looting by comparing it with the Boston Tea Party. I find it hard to believe that Blow doesn’t know what happened after they threw the tea into the water – they not only stripped naked and castigated a fellow Son of Liberty after they found out that he had secretly pocketed the tea, but they came back later and replaced the lock of the ship they had broken. Unlike the looters, the Boston Patriots had a profound respect for private property. In fact, it was precisely British insults to private property by way of quartering soldiers in private residences that served as a spark for the revolution. In addition, as Richard Rothstein painstakingly documents in his superb book "The Color of Law", laws were explicitly enacted precisely to deny African-Americans and other minorities access to private housing for decades, so it's ironic to see mobs destroying private property in their own communities and crippling the livelihoods of folks - many of whom are poor immigrants with small businesses - who had nothing to do with the cause of the protests.

    But all these distinctions were lost, especially at the New York Times who tied themselves up into a real knot by publishing an op-ed by Senator Tom Cotton. In the last few years Cotton has emerged as one of the most racist and xenophobic of all Trump supporters and I detest him. Cotton wrote a biased and flawed op-ed that called for the army to step in to pacify cities where looting was taking place. Knowing his past this was a convenient position for him and I completely disagreed with it; I did think there needed to be some way for law and order to be imposed, but the last thing we need in the middle of a militarized police force is the actual military. Nevertheless, it turned out that a fair percentage of the country agreed with him, including a fair share of Democrats, and Cotton is a sitting United States senator after all, so as an elected public official his views needed to be known, not because they were right but because they were relevant. I suddenly felt newfound respect for the New York Times for airing dissenting views that would allow their readers to get out of their echo chambers and take a stroll in a foreign country, but it didn't last long. As we now know, there was a virtual coup inside the paper and the op-ed editor resigned. As Andrew Sullivan said in a must-read piece it is deeply troubling when an ideological faction – any ideological faction – can hold a news source hostage and force it to publish only certain viewpoints conducive to their own thinking.

    A similar reaction against what were entirely reasonable responses to the looting spilled over into other institutions and individuals’ lives. In perhaps the most bizarre example, David Shor who is an analyst at a New York City firm - and whose Twitter profile literally includes the phrase “I try to elect Democrats” - was fired for tweeting a study by a black professor at Princeton that said that non-violent protests are more effective than violent ones. Just chew on that a bit: an individual was fired merely for tweeting, and not just tweeting anything but tweeting something that MLK Jr. would have heartily approved of. When people actually face retribution for pointing out that non-violence works better than violence, you do feel like you are in a mirror universe.

    Second: The statue controversy. The killing of Floyd set off a wave of protests that extended to many other areas, some because of feuds brewing for years; for more than a hundred years in this particular case. I am all for the removal of Confederate Statues; there is nothing that is redeeming in them, especially since many of them were put up by white supremacists decades after the war ended. While the bigger issue of acknowledging memory and history is complicated, the latest ray of light for me came from Eliot Cohen, a dean at Johns Hopkins who cut through the convoluted thicket to come up with a simple rule that’s as clear as anything in my opinion for weighing historical figures in the scales of justice. Cohen asked those who were demanding the statues to be taken down to ask if the thing that they were criticizing a person for was the most important thing he or she was known for. This question immediately creates a seismic divide between Confederates and Founding Fathers. If the Civil War had not happened, Robert E. Lee would have been a better than average soldier who fought with distinction during the Mexican-American War. If Thomas Jefferson had never owned and abused slaves and had illegitimate children with Sally Hemings, he would have still been the father of religious freedom, the Louisiana Purchase, the University of Virginia, scientific inquiry and the Declaration of Independence – a document that, even if it was not applied universally, had such abstract power that it kept on being cited all the time by figures as diverse as Abraham Lincoln and Ho Chi Minh, not to mention Frederick Douglass and MLK Jr. Jefferson would have still done these great things if you took away his slavery and hypocrisy. Washington is even more unimpeachable since he led the country to freedom during the war and unlike Jefferson freed his slaves. The fact that these were flawed men who still did great things is hardly a novel revelation.

    Sadly, you know that your side is losing the war of ideas when they start handing propaganda victories to the side you despise on a platter. Three years ago, in the context of a Lee statue that was going to be taken down, after that terrible anti-Semitic Charlottesville rally by white supremacists, Trump made a loathsome remark about there being “fine people” on all sides and also asked a journalist that if it was Lee today, would it be Jefferson or Washington next? I of course dismissed Trump’s remark as racist and ignorant; he would not be able to recite the Declaration of Independence if it came wafting down at him in a MAGA hat. But now I am horrified that liberals are providing him with ample ammunition by validating his words. A protest in San Francisco toppled a statue of Ulysses S. Grant – literally the man who defeated the Confederacy and destroyed the first KKK – and defaced a statue of Cervantes, a man who as far as we know did not write “Don Quixote” while he was relaxing from a day’s fighting for the Confederacy or abusing slaves. University of Wisconsin students recently asked for a statue of Lincoln to be removed because he had once said some uncomplimentary words about black people. And, since it was just a matter of time, the paper of record just published an op-ed calling for the Jefferson Memorial in Washington to be taken down. Three years ago, if you had asked me if my fellow liberals would go from Robert E. Lee to Jefferson and Washington and Grant so quickly, I would have expressed deep skepticism. But here we are, and based on recent events it won’t be paranoid at all to ask that if Washington statues are next, would streets or schools named after Washington also be added to the list? How about statues of Plato and Aristotle who supported slavery as a natural state of man? And don’t even get me started on Gandhi who said some very unflattering words about Africans. The coefficient of friction on the slippery slope is rapidly going to zero.

    Third item in the parade of items signifying a spiraling descent into intolerance - A call to bar Steven Pinker from the Linguistic Society of America’s list of distinguished fellows and media experts. This call would be laughable if it weren’t emblematic of a deeper trend. My fellow liberal Scott Aaronson has already indicated the absurdity of the effort in his post not in the least because Pinker has championed liberalism, evidence-based inquiry and rational thought all throughout his long career. The depressing thing is that the tactics are not new: guilt by association, cherry-picking, an inability to judge someone by the totality of their behavior or contributions, no perception of gray in an argument and so on. The writers don’t like the fact that Pinker tweeted a study showing that police encounters with black people aren’t particularly violent (but that there are more encounters to begin with, so the probability of one turning violent is higher), tweeted that a horrific fatal attack by a disgruntled man at UCSB on women did not imply higher rates of violence against women in general and said in his widely-praised book “The Better Angels of our Nature” that a seemingly mild-mannered man in New York City shockingly turned out to be violent. Pinker has never denied the suffering of individuals but has simply pointed out that that suffering should not blind us to progress at large. As hard is it might be to believe this, liberals are punishing someone who says that the world has at large become a better place because we have embraced liberal values. Again, this feels like we have stepped into a surreal mirror universe.

    As biologist Jerry Coyne has explained on his blog, none of these accusations hold water and the protestors are on exceedingly thin ice, but what is noteworthy is the by now all-too-common accusation by selective misrepresentation and the detailed combing through (and a disastrous one at that) of every tweet, every “like” from Pinker that would be evidence of his awfulness as a human being and affront to the orthodoxy. If this does not seem like a job for an incompetent and yet obsessive Orwellian bureaucrat or a member of the NKVD during Stalin’s show trials, I don’t know what is (as Robert Conquest described in his famous account of Stalin’s purges, going through someone’s entire life history with a fine-toothed comb and holding up even the slightest criticism of the dear leader or disagreement with party orthodoxy was almost de rigueur for the Soviets and the Stasi). Perhaps completely unsurprisingly, the doyen of American linguistics, Noam Chomsky, refused to sign the letter and instead signed the other one; Chomsky has consistently been an exemplary supporter of free speech and has famously pointed out that if you support only free speech that you like, you are no different from Goebbels who was also a big fan of speech he liked. But Pinker’s example again goes to show that the slippery slope argument is no longer a fictitious one or a strawman. If we went from Milo Yiannopoulos to Steven Pinker in three years, it simply does not feel paranoid to think that we could get to a very troubling place in three more years.

    The whole development of course is very sad, certainly a tragedy but rapidly approaching a farce. Liberals and Democrats were supposed to be the party of free speech and intelligent dialogue and tolerance and viewpoint diversity. The Republican Party, meanwhile, is not a political party anymore but a “radical insurgency” as Chomsky puts it. It is a blot not just on true conservatism but on common sense and decency. The reason I feel particularly concerned this year is because I have always felt that, with Republicans having descended into autocracy and madness, liberal Democrats are the one and only thing standing between democracy and totalitarianism in this country. I have been disillusioned with their abandonment of unions and disparaging of “middle America” for a long time, but I still thought they upheld traditional, age-old liberal values. With Republicans not even making a pretense of doing this, one would think the Democrats have a golden opportunity to pick up the baton here. But instead you have a party that has embraced diversity provided it’s of the kind they like, allows for no nuance or sliding scale of disagreement, accuses people of being some kind of “ist” with the spirit of the Inquisition and refuses to see individuals as individuals rather than as part of their favorite or their despised groups. If Democrats give up on us, what other group of influence can save the country?

    Quite apart from how this behavior abandons the values that have made this country a great one, it is a disastrous political strategy. Currently, the number one goal of any American citizen with any amount of decency and intelligence should be to hand Donald Trump and his unscientific, racist, ignorant administration the greatest defeat in American electoral history. Almost nothing else is as important this year. There are sadly still people who are on the fence – these people cannot let go of the Republican Party for one reason or another, but especially in the last few months one hopes that enough of them have become disillusioned with the Trump administration’s utter incompetence, casual cruelty and dog whistle signaling to consider voting for the other guy. The Democrats should be welcoming these people into their ranks with open arms, so would it be harder or easier for fence-sitters to think of voting Democrat when they see self-proclaimed Democrats toppling random statues, unleashing Twitter mobs on people they disagree with and trying to destroy their careers and basically trying to disparage or eliminate anyone who may think slightly differently from the sphere of discourse?

    I came to this country as an immigrant, and while several reasons brought me here just like they do all immigrants, science and technology and freedom of speech were the top two things that I loved and continue to love about the United States. When I was growing up in India, my father who was an economics professor at a well-known college used to tell me how he taught econometrics classes during the Indian Emergency of the 1970s when the Constitution was suspended by the Prime Minister, Indira Gandhi. He told me how he used to occasionally see a government agent standing behind during his classes, taking notes, making sure he was not saying something subversive. It can only be amusing if parts of partial different equations used in econometrics were regarded as subversive (and if the agents understood them), but it was nonetheless a sobering experience. It would have been far worse had my father lived in Cambodia during the same time. While it’s to India’s democratic credit that it escaped from that hole, even today much of freedom of speech in India, while enshrined in the Constitution, is on paper. As several recent incidents have shown, you can get in trouble if you criticize the government, and in fact you can get in trouble even from your fellow citizens who may rat you out and file lawsuits against you. Even in Britain you have libel laws, and of course free speech is non-existent in countries like Saudi Arabia. In my experience, Americans who haven’t lived abroad often don’t appreciate how special their country is when it comes to free speech. Sadly, as the current situation shows, we shouldn’t take it for granted.

    When I complain about problems with free speech in this country, fellow liberals tell me – as if I have never heard of the US Constitution - how it only means that the government cannot arrest you if you say something incendiary. But this point is moot since people can stifle each other’s ideas as thoroughly as the government does, and while informal censure has been around since we were hunter gatherers, when it gets out of hand as it seems to these days, one can see a pall of conformity and a lack of diversity descending over the country. This also puts in a dim light the objection that there cannot be speech without consequences – as David Shor’s example shows, if the results include getting fired or booted out from professional organizations for almost anything you say, these “consequences” are almost as draconian as government oppression and should be unacceptable. As he did with many things, John Stuart Mill said it best in his “On Liberty”,

    “Protection, therefore, against tyranny of the magistrate is not enough: there needs protection also against the tyranny of the prevailing opinion and feeling; against the tendency of society to impose, by other means than civil penalties, its own ideas and practices as rules of conduct on those who dissent from them; to fetter the development, and, if possible, prevent the formation, of any individuality not in harmony with its ways, and compel all characters to fashion themselves upon the model of its own.”

    It’s also worth remembering that there is much less distinction between “the people” and “the government” than we think since today’s illiberal anti-free speech activists are tomorrow’s politicians, community leaders, writers and corporate leaders. And we would be laboring under a truly great illusion if we think that these supposedly well-intentioned activists cannot become repressive; everyone can become repressive if given access to power. The ultimate question is not whether we want a government which does not tread on our freedom - we settled that question in 1787 - it’s about what kind of country we want to live in: one in which ideas, even unpleasant ones, are confronted with other ideas in a sphere of spirited public debate, or one in which everyone boringly thinks the same thing, there is no opportunity for dissent, nuanced thinking is thrown out of the window and anybody who challenges the orthodoxy is to be eliminated from public discourse one way or another? Because those are definitely not the values that made this country the envy of the world and the one that its founding ideals envisaged.

    So what should those of us who squarely believe in free speech, viewpoint diversity, dialogue and good faith debate do? This year it has become clear that we should take a stand, and as Scott indicates, if supposedly traditional, plain vanilla liberal values like speech without harsh retaliation - values which go back to the founding of the country and beyond – are suddenly “radical” values that are increasingly the province of a narrow minority, so be it: we should not only embrace these radical values with alacrity but be unhesitant and full-throated in their defense. The signers of the Harper’s Weekly letter have set an excellent precedent, and they are saying something very simple – if you want to call yourself a liberal, act liberal.