Consciousness: Pushing the boundaries of science and pseudoscience

I attended a conference in La Jolla last week with the ambitious title, “The Science of Consciousness”. As it brought together neuroscientists, psychologists, biologists, physicists (like Roger Penrose), mathematicians, linguists (like Noam Chomsky), and many others, I looked forward to a variety of perspectives, including those outside the mainstream, but I got more than I bargained for. It turns out that it also included people more involved in various kinds of spirituality, wellness, meditation, and…interesting artistic interpretations.

(Image by Robert Fludd, 1619, Wikimedia Commons.)

Instead of shedding light on something as perplexing and seemingly impenetrable as consciousness, which people have been trying to understand for millennia, these other approaches threaten to undermine the whole enterprise. I worry that some of the conference could be better characterized as “The Pseudoscience of Consciousness.” And the distinction between science and pseudoscience never seemed more blurred.

But what do I know. Science hasn’t really given us that much of an understanding of the murky concept. What is consciousness and do only humans have it? What about babies and the elderly and people with debilitating mental illnesses? Exactly what parts of the brain are involved (just the frontal cortex? microtubules in neurons everywhere?) and how did it appear in evolution?

Science is only getting us so far, and consciousness is a fundamental conundrum of the human condition, so why not consider other avenues toward probing it? But some people aren’t doing that argument any favors. There’s people like Deepak Chopra (who was at the conference) who add the word “quantum” to their speculative if not fanciful ideas to try to make them profound or something. That’s B.S. (And anyway, the interpretation of the quantum behavior of particles and waves remains disputed and poorly understood since their discovery some 90 years ago, so that’s not the best reference to make!)

I’m glad people continue to speculate and investigate different facets of consciousness, such as how we’re conscious about our perceptions of language and conversation, music, making and retrieving memories, etc. Some scientists are also studying the kinds of neuronal activity that are dampened by anesthetics and enhanced by psychoactive drugs, which sounds weird, but it might illuminate, just a bit, what’s going on in our parts of our complex brains.

I’m also glad that people aren’t limiting this endeavor science. After all, poets, philosophers, musicians can make insights no one else has thought of before, and we need to listen to them. But when there’s the risk of pseudoscience being passed off as science and gaining legitimacy at the expense of it, then we have a problem.

Maybe this sort of thing is inevitable when you’re pushing the frontiers of something unknown while answers remain illusive. For example, think of interstellar space exploration, which also naturally captivates the imagination of a wide range of people. At times the consciousness conference reminds me of parts of the “Finding Earth 2.0” conference organized by 100-Year Starship that I went to back in 2015. While some impressive people like Jill Tarter and Mae Jameson focused on space travel technology and the search for extraterrestrial intelligence (SETI), other people worked on things like “astrosociology.” I was expecting people to talk about what it might be like for a handful of people to be stuck in an enclosed spaceship for years or a slightly larger planetary colony for decades. Those are important and tractable questions—and scientists at NASA and elsewhere are studying them right now. But instead a handful of people spoke about giant ships at least a century in the future, like it was Battlestar Galactica or the starship Enterprise or something. Yes, let’s think about what things might be like in the 23rd century, but all that’s premature unless we figure out how to get there first.

Why do we engage in space exploration?

A review of diverse perspectives on space exploration and extraterrestrial life reveal fundamentally human hopes, fears and flaws

Since the dawn of civilization thousands of years ago, humans have looked to the skies. Archaeologists have found evidence of people from China, India, and Persia to Europe and Mesoamerica observing and contemplating the many stars and planets that fascinated them. We humans have also wondered about—and often hoped for—the existence of other intelligent life out there. Considering the large number of planets in the Milky Way and in billions of other galaxies, perhaps we are not alone, and maybe even while you are reading this, extraterrestrials could be looking in our direction through their telescopes or sending us interstellar telegrams. But if our galaxy teems with aliens, following Italian physicist Enrico Fermi’s persistent question, we must ask, “Where are they?”

Artist's depiction of a travel poster for a "Tatooine-like" planet orbiting two suns, recently discovered by NASA's Kepler spacecraft. (Courtesy: NASA)

Artist’s depiction of a travel poster for a “Tatooine-like” planet orbiting two suns, recently discovered by NASA’s Kepler spacecraft. (Courtesy: NASA)

Two recent pieces in the New Yorker and New York Times, as well as numerous books over the past couple years, motivate me to consider this and related questions too. Astronomers and astrophysicists around the world, including scientists working with NASA, the European Space Agency (ESA), the Japanese Space Agency (JAXA) and many others, have many varieties of telescopes and observatories on Earth and in space, just because we want to investigate and learn about our galactic neighborhood and beyond. We also attempt to communicate, like sending a message in a bottle, with the Golden Records aboard the Voyager spacecrafts, and we listen for alien attempts to contact us. In our lifetime, we have dreams of sending humans to Mars and to more distant planets. Why do we do this? We do it for many reasons, but especially because humans are explorers: we’re driven to see what’s out there and to “boldly go where no one has gone before.” As Carl Sagan put it in Cosmos, “Exploration is in our nature. We began as wanderers, and we are wanderers still.”

Views of human space exploration

Elizabeth Kolbert reviews three recently published and forthcoming books by Chris Impey, an astronomer at the University of Arizona (where I used to work three years ago), Stephen Petranek, a journalist at Discover, and Erik Conway, a historian of science at Jet Propulsion Laboratory. (She did not mention an award-winning book by Lee Billings, Five Billion Years of Solitude, which I will review in a later post.) She fault finds with the overoptimistic and possibly naïve “boosterism” of Impey and Petranek. “The notion that we could…hurl [humans]…into space, and that this would, to use Petranek’s formulation, constitute ‘our best hope,’ is either fantastically far-fetched or deeply depressing.” She asks, “Why is it that the same people who believe we can live off-Earth tend to believe we can’t live on it?”

Kolbert’s assessment has some merit. Astrophiles and space enthusiasts, of which I am one, sometimes seem to neglect Earth (and Earthlings) in all its wonder, marvels, complexity, brutality and messiness. But is the primary reason for exploring the universe that we can’t take care of ourselves on Earth? Mars should not be viewed as a backup plan but rather as one of many important steps toward better understanding our little corner of the galaxy. Furthermore, we should be clear that sending humans to Mars and more distant worlds is an incredibly complicated and dangerous prospect, with no guarantee of success. Even if the long distances could be traversed—at its closest, Mars comes by at least a staggering 50 million miles (80 million km) away, and then the nearest star, Alpha Centauri, is about 25 trillion miles from us—future human outposts would face many obstacles. The popular novel by Andy Weir, The Martian, demonstrates only some of the extraordinary challenges of living beyond our home planet.

Overview of components of NASA's Journey to Mars program, which seeks to send humans to the red planet in the 2030s. (Credit: NASA)

Overview of components of NASA’s Journey to Mars program, which seeks to send humans to the red planet in the 2030s. (Credit: NASA)

Though Kolbert criticizes Conway’s dry writing style, she clearly sympathizes with his views. “If people ever do get to the red planet—an event that Conway…considers ‘unlikely’ in his lifetime—they’ll immediately wreck the place just by showing up…If people start rejiggering the atmosphere and thawing the [planet’s soil], so much the worse.” This line of criticism refers to flaws of geoengineering and of the human species itself. Many times in history, humans ventured out acting like explorers, and then became colonists and then colonialists, exploiting every region’s environment and inhabitants.

Note that Kolbert is a journalist with considerable experience writing about climate, ecology and biology, while astrophysics and space sciences require a stretch of her expertise. In her excellent Pulitzer Prize-winning book, The Sixth Extinction, Kolbert argues provocatively that humans could be viewed as invasive species transforming the planet faster than other species can adapt, thereby constituting a danger to them. “As soon as humans started using [language], they pushed beyond the limits of [the] world.” I agree that humans must radically improve their relationship with nature and Earth itself, but this does not preclude space travel; on the contrary, the goal of exploring other worlds should be one aspect of our longer-term and larger-scale perspective of humanity’s place in the universe.

Views of extraterrestrial intelligence

Dennis Overbye, a science writer specializing in physics and astronomy, covers similar ground, but focuses more on the search for extraterrestrial intelligence (SETI). He mentions the Drake Equation, named after the American astronomer Frank Drake, which quantifies our understanding of the likelihood of intelligent life on other planets with whom we might communicate. Both Drake and Sagan “stressed that a key unknown element in their equations was the average lifetime of technological civilizations.” If advanced species don’t survive very long, then the possibility of contact between overlapping civilizations becomes highly improbable. It would be unfortunate if similarly advanced civilizations, like Earthlings and Klingons, could never meet.

Overbye introduces the controversial University of Oxford philosopher, Nick Bostrom, who is rooting for us to fail in our search for ETs! “It would be good news if we find Mars to be sterile. Dead rocks and lifeless sands would lift my spirit.”

Bostrom bases his argument on a concept he refers to as the Great Filter. Considering the likelihood of advanced civilizations, many conditions and criteria must be satisfied and steps must be taken before a planet in the “habitable zone” has a chance of harboring intelligent life. The planet probably must have the right kind of atmosphere and a significant amount of liquid water and some kind of possibly carbon-based building blocks of life, and after that, the alien species’ evolutionary developments could go in any direction, not necessarily in a direction that facilitates intelligence. In addition, asteroids, pandemics, or volcanic eruptions could wipe out this alien life before it got anywhere. In other words, myriad perils and difficulties filter out the planets, such that only a few might have species that survive and reach a level of social and technological advancement comparable to those of humans.

On the other hand, if we do find life on other planets and if intelligent extraterrestrial life is relatively ubiquitous, our lack of contact with them could mean that advanced civilizations have a short lifetime. Perhaps the Great Filter is ahead of us, “since there is no reason to think that we will be any luckier than other species.” Maybe nuclear war, climate change, or killer robots might wipe us out before we have the chance to explore the galaxy.

I am not convinced by Bostrom’s pessimism. Even if the Great Filter is ahead of us, implying that humans face more existential threats in the future than have been overcome in the past, this doesn’t mean that we are doomed. Humanity does have major problems with acknowledging large-scale impacts and long-term outlooks, but I hope we could learn to change before it is too late.

A more positive outlook

We have learned a lot about planets, stars, galaxies, black holes and the distant universe from our tiny vantage point. But we would be immodest and mistaken to brazenly presume that we’ve already figured out the rest of the universe. We really don’t know how many other “intelligent” species might be out there, and if so, how far they are, what level of evolution they’re at (if evolution is a linear process), or whether or how they might communicate with us. We should continue to discuss and examine these questions though.

While traveling to other planets will take a long time, in the meantime astronomers continue to make exciting discoveries of possibly “Earth-like” planets, such as Kepler-452b, an older bigger cousin to our world. It seems likely that the Earth has a very big family, with many cousins in the Milky Way alone.

So why do we engage in space exploration and why do we seek out extraterrestrial life? This question seems to transform into questions about who we are and how we view our role in the universe. I believe that humans are fundamentally explorers, not only in a scientific sense, and we have boundless curiosity and wonder about our planet and the universe we live in. Humans also explore the depths of the oceans and dense rainforests and they scour remote regions in arid deserts and frigid glaciers (while they still remain), just to see what they’re like and to look for and observe different lifeforms.

More importantly, even after tens of thousands of years of human existence, we are still exploring who we are, not just with scientific work by psychologists and sociologists but also with novelists, poets and philosophers. We still have much to learn. To quote from Q, a capricious yet occasionally wise Star Trek character, “That is the exploration that awaits you: not mapping stars and studying nebulae, but charting the unknown possibilities of existence!”

Tussles in Brussels: How Einstein vs Bohr Shaped Modern Science Debates

In one corner, we have a German-born theoretical physicist famous for his discovery of the photoelectric effect and his groundbreaking research on relativity theory. In the opposite corner, hailing from Denmark, we have a theoretical physicist famous for his transformational work on quantum theory and atomic structure. Albert Einstein and Niels Bohr frequently butted heads over the interpretation of quantum mechanics and even over the scope and purpose of physics, and their debates still resonate today.

Niels Bohr and Albert Einstein (photo by Paul Ehrenfest, 1925).

Niels Bohr and Albert Einstein (photo by Paul Ehrenfest, 1925).

In a class on “Waves, Optics, and Modern Physics,” I am teaching my students fundamentals about quantum physics, and I try to incorporate some of this important history too. In the early 20th century, physicists gradually adopted new concepts such as discrete quantum energy states and wave-particle duality, in which under certain conditions light and matter exhibit both wave and particle behavior. Nevertheless, other quantum concepts proposed by Bohr and his colleagues, such as non-locality and a probabilistic view of the wave function, proved more controversial. These are not mere details, as more was at stake—whether one can retain scientific realism and determinism, as was the case with classical physics, if Bohr’s interpretation turns out to be correct.

Bohr had many younger followers trying to make names for themselves, including Werner Heisenberg, Max Born, Wolfgang Pauli, and others. As experimental physicists explored small-scale physics, new phenomena required explanations. One could argue that some of Bohr and his followers’ discoveries and controversial hypotheses were to some extent just developments of models that managed to fit the data, and the models needed a coherent theoretical framework to base them on. On the other hand, Einstein, Erwin Schrödinger, and Louis de Broglie were skeptical or critical about some of these proposals.

The debates between Einstein and Bohr came to a head as they clashed in Brussels in 1927 at the Fifth Solvay Conference and at the next conference three years later. It seems like all of the major physics figures of the day were present, including Einstein, Bohr, Born, Heisenberg, Pauli, Schrödinger, de Broglie, Max Planck, Marie Curie, Paul Dirac, and others. (Curie was the only woman there, as physics had an even bigger diversity problem back then. The nuclear physicist Lise Meitner came on the scene a couple years later.)

Conference participants, October 1927. Institut International de Physique Solvay, Brussels.

Conference participants, October 1927. Institut International de Physique Solvay, Brussels.

Einstein tried to argue, with limited success, that quantum mechanics is inconsistent. He also argued, with much more success in my opinion, that (Bohr’s interpretation of) quantum mechanics is incomplete. Ultimately, however, Bohr’s interpretation carried the day and became physicists’ “standard” view of quantum mechanics, in spite of later developments by David Bohm supporting Einstein’s realist interpretation.

Although the scientific process leads us in fruitful directions and encourages us to explore important questions, it does not take us directly and inevitably toward a unique “truth.” It’s a messy nonlinear process, and since scientists are humans too, the resolution of scientific debates can depend on historically contingent social and cultural factors. James T. Cushing (my favorite professor when I was an undergraduate) argued as much in his book, Quantum Mechanics: Historical Contingency and the Copenhagen Hegemony.

Why do the Einstein vs Bohr debates still fascinate us—as well as historians, philosophers, and sociologists—today? People keep discussing and writing about them because these two brilliant and compelling characters confronted each other about issues with implications about the scope and purpose of physics and how we view the physical world. Furthermore, considering the historically contingent aspects of these developments, we should look at current scientific debates with a bit more skepticism or caution.

Implications for Today’s Scientific Debates

In recent years, we have witnessed many intriguing disagreements about important issues in physics and astrophysics and in many other fields of science. For example, in the 1990s and 2000s, scientists debated whether the motions, masses, and distributions of galaxies were consistent with the existence of dark matter particles or whether gravitational laws must be modified. Now cosmologists disagree about the likely nature of dark energy and about the implications of inflation for the multiverse and parallel universes. And string theory is a separate yet tenuously connected debate. On smaller scales, we have seen debates between astrobiologists about the likelihood of intelligent life on other planets, about whether to send missions to other planets, and even disagreements about the nature of planets, which came to the fore with Pluto‘s diminished status.

Scientists play major roles in each case and sometimes become public figures, including Stephen Hawking, Neil deGrasse Tyson, Roger Penrose, Brian Greene, Sean Carroll, Max Tegmark, Mike Brown, Carolyn Porco, and others. Moreover, many scientists are also science communicators and actively participate in social media, as conferences aren’t the only venues for debates anymore. For example, 14 of the top 50 science stars on Twitter are physicists or astronomers. Many scientists communicate their views to the public, and people want to hear them weigh in on important issues and on “what it all means.” (Contrary to an opinion expressed by deGrasse Tyson, physicists are philosophers too.)

In any case, as scientific debates unfold, we should keep in mind that sometimes we cannot find a unique elegant explanation to a phenomenon, or if such an explanation exists, it may remain beyond our grasp for a long time. Furthermore, we should keep our minds open to the possibility that our own interpretation of a scientific phenomenon could be incomplete, incoherent, or even incorrect.

Exploring the “Multiverse” and the Origin of Life

After two weeks away from the blog, I’m back! At the end of July, I attended an interesting event at UC San Diego’s Arthur C. Clarke Center for Human Imagination. (Yes, that’s what it’s called!) The event was a panel discussion entitled, “How Big is the World?: Exploring the Multiverse in Modern Astrophysics, Cosmology, and Beyond” (and you can watch the event here). The three speakers included Andrew Friedman (postdoctoral fellow in astronomy at MIT), Brian Keating (professor of physics in my department at UCSD), and David Brin (Hugo & Nebula Award Winning Author).

The Clarke Center seems to be a unique place with an ambitious program that incorporates a variety of “transdisciplinary” activities. This event fits with their nebulous theme, and the talks and discussions frequently overlapped between science, philosophy of science, and science fiction. I think science and philosophy of science go well together especially when we’re exploring the edges of scientific knowledge, including cosmological astrophysics and the origins of human life. (See my previous post and this recent article on Salon.) Too often astrophysicists, myself included, become very specialized and neglect the “big questions.” Nonetheless, I think we should be careful when we traverse the border between science and science fiction: while it’s exciting to connect them and useful for public outreach, we should mind the gap.

Andrew Friedman focused on the “multiverse”. What is a multiverse, you ask? I’m not entirely clear on it myself, but I’ll try to explain. In the first fraction of a second of the Big Bag, the universe appears to have gone through a phase of accelerated, exponential expansion (called “inflation”) driven by the vacuum energy of one or more quantum fields. The gravitational waves that were recently detected by BICEP2 (in which Brian Keating was involved) appear to support particular inflationary models in which once inflation starts, the process happens repeatedly and in multiple ways. In other words, there may be not one but many universes, including parallel universes—a popular topic in science fiction.

multiverse-magazine-illustration-01_77755_990x742

Inflationary theory solves some problems involving the initial conditions of the Big Bang cosmology, but I’m not so sure that we have—or can ever have—evidence clearly pointing to the existence of multiverses. In addition, in my opinion, Friedman stretched the concept of “universe” to try to argue for the multiverse. He spoke about the fact that there are parts of the universe that are completely inaccessible even if we could go the speed of light, but that doesn’t mean that the inaccessible regions are another universe. It’s fun to think about a “quantum divergence of worlds,” as David Brin referred to it, but quantum mechanics (with the standard Copenhagen interpretation; see this book by Notre Dame professor Jim Cushing) don’t imply a multiverse either: Schrödinger’s live cat and dead cat are not in separate universes. As far as I know, I’m not creating new universes every time I barely miss or catch the train.

The speakers did bring up some interesting questions though about the “anthropic principle” and “fine tuning.” The anthropic principle is a contentious topic that has attracted wide interest and criticism, and if you’re interested, read this review of the literature by Pittsburgh professor John Earman. The anthropic principle is the idea that the physical universe we observe must be compatible with conscious life. It’s a cosmic coincidence that the density of vacuum energy and matter are nearly equal and that the universe’s expansion rate is nearly equal to the critical rate which separates eternal expansion from recontraction, and if the universe were significantly different, it would be impossible to develop conscious life such as humans who can contemplate their own universe. (In the context of the multiverse, there may be numerous universes but only a tiny fraction of them could support life.) It’s important to study the various coincidences and (im)probabilities in physics and cosmology in our universe, but it’s not clear what these considerations explain.

David Brin spoke differently than the others, since he’s more a writer than a scientist, and his part of the discussion was always interesting. He frequently made interesting connections to fiction (such as a legitimate criticism of Walt Whitman’s “Learn’d Astronomer“) and he had a poetic way of speaking; when talking about the possibility of life beyond Earth, he said “If there are living creatures on Titan, they will be made of wax.” He also brought up the “Drake equation,” which is relevant in the context of the topics above. The Drake equation is a probabilistic expression for estimating the number of active, communicating civilizations in our galaxy. It involves a multiplication of many highly uncertain quantities (see this xkcd comic), but it’s nonetheless interesting to think about. The problem is that space is really big—”vastly, hugely, mindbogglingly big,” according to Douglas Adams—so even if there are Vulcans or Klingons or dozens or millions of other civilizations out there, it would take a really really really long time to find them and attempt to communicate with them. We could send people from Earth in a long shuttle ride to visit another civilization, but there’s no guarantee that humanity will still be around when they try to call back. It’s unfortunate, but this is the universe we live in.

Paradigm Shifts?

In addition to physics and astronomy, I used to study philosophy of science and sociology. In my opinion, many scientists could learn a few things from sociologists and philosophers of science, to help them to better understand and consider how scientific processes work, what influences them and potentially biases scientific results, and how science advances through their and others’ work. In addition, I think that people who aren’t professional scientists (who we often simply call “the public”) could better understand what we are learning and gaining from science and how scientific results are obtained. I’ll just write a few ideas here and we can discuss these issues further later, but my main point is this: science is an excellent tool that sometimes produces important results and helps us learn about the universe, our planet, and ourselves, but it can be a messy and nonlinear process, and scientists are human–they sometimes make mistakes and may be stubborn about abandoning a falsified theory or interpretation. The cleanly and clearly described scientific results in textbooks and newspaper articles are misleading in a way, as they sometimes make us forget the long, arduous, and contentious process through which those results were achieved. To quote from Carl Sagan (in Cosmos), who inspired the subtitle of this blog (the “pale blue dot” reference),

[Science] is not perfect. It can be misused. It is only a tool. But it is by far the best tool we have, self-correcting, ongoing, applicable to everything. It has two rules. First: there are no sacred truths; all assumptions must be critically examined; arguments from authority are worthless. Second: whatever is inconsistent with the facts must be discarded or revised.

As you may know, the title of this post refers to Thomas Kuhn (in his book, The Structure of Scientific Revolutions). “Normal science” (the way science is usually done) proceeds gradually and is based on paradigms, which are collections of diverse elements that tell scientists what experiments to perform, which observations to make, how to modify their theories, how to make choices between competing theories and hypotheses, etc. We need a paradigm to demarcate what is science and to distinguish it from pseudo-science. Scientific revolutions are paradigm shifts, which are relatively sudden and unstructured events, and which often occur because of a crisis brought about by the accumulation of anomalies under the prevailing paradigm. Moreover, they usually cannot be decided by rational debate; paradigm acceptance via revolution is essentially a sociological phenomenon and is a matter of persuasion and conversion (according to Kuhn). In any case, it’s true that some scientific debates, especially involving rival paradigms, are less than civil and rational and can look something like this:
calvin_arguing

I’d like to make the point that, at conferences and in grant proposals, scientists (including me) pretend that we are developing research that is not only cutting edge but is also groundbreaking and Earth-shattering; some go so far as to claim that they are producing revolutionary (or paradigm-shifting) research. Nonetheless, scientific revolutions are actually extremely rare. Science usually advances at a very gradual pace and with many ups and downs. (There are other reasons to act like our science is revolutionary, however, since this helps to gain media attention and perform outreach in the public, and it helps policy-makers to justify investments in basic research in science.) When a scientist or group of scientists does obtain a critically important result, it is usually the case that others have already produced similar results, though perhaps with less precision. Credit often goes to a single person who packaged and advertised their results well. For example, many scientists are behind the “Higgs boson” discovery, and though American scientists received the Nobel Prize for detecting anisotropies in the cosmic microwave background with the COBE satellite, Soviets actually made an earlier detection with the RELIKT-1 experiment.

einstein-bohr

Let’s briefly focus on the example of quantum mechanics, in which there were intense debates intense debates in the 1920s about (what appeared to be) “observationally equivalent” interpretations, which in a nutshell were either probabilistic or deterministic and realist ones. My favorite professor at Notre Dame, James T. Cushing, wrote a provocative book on the subject with the subtitle, “Historical Contingency and the Copenhagen Hegemony“. The debates occurred between Neils Bohr’s camp (with Heisenberg, Pauli, and others, who were primarily based in Copenhagen and Göttingen) and Albert Einstein’s camp (with Schrödinger and de Broglie). Bohr’s younger followers were trying to make bold claims about QM and to make names for themselves, and one could argue that they misconstrued Einstein’s views. Einstein had essentially lost by the 1930s, in which the nail in the coffin was von Neumann’s so-called impossibility proof of “hidden variables” theories–a proof that was shown to be false thirty years later. In any case, Cushing argues that in decisions about accepting or dismissing scientific theories, sometimes social conditions or historical coincidences can play a role. Mara Beller also wrote an interesting book about this (Quantum Dialogue: The Making of a Revolution), and she finds that in order to understand the consolidation of the Copenhagen interpretation, we need to account for the dynamics of the Bohr et al. vs. Einstein et al. struggle. (In addition to Cushing and Beller, another book by Arthur Fine, called The Shaky Game, is also a useful reference.) I should also point out that Bohr used the rhetoric of “inevitability” which implied that there was no plausible alternative to the Copenhagen paradigm. If you can convince people that your view is already being adopted by the establishment, then the battle has already been won.

More recently, we have had other scientific debates about rival paradigms, such as in astrophysics, the existence of dark matter (DM) versus modified Newtonian dynamics (MOND); DM is more widely accepted, though its nature–whether it is “cold” or “warm” and to what extent it is self-interacting–is still up for debate. Debates in biology, medicine, and economics, are often even more contentious, partly because they have policy implications and can conflict with religious views.

Other relevant issues include the “theory-ladenness of observation”, the argument that everything one observes is interpreted through a prior understanding (and assumption) of other theories and concepts, and the “underdetermination of theory by data.” The concept of underdetermination dates back to Pierre Duhem and W. V. Quine, and it refers to the argument that given a body of evidence, more than one theory may be consistent with it. A corollary is that when a theory is confronted with recalcitrant evidence, the theory is not falsified, but instead, it can be reconciled with the evidance by making suitable adjustments to its hypotheses and assumptions. It is nonetheless the case that some theories are clearly better than others. According to Larry Laudan, we should not overemphasize the role of sociological factors over logic and the scientific method.

In any case, all of this has practical implications for scientists as well as for science journalists and for people who popularize science. We should be careful to be aware of, examine, and test our implicit assumptions; we should examine and quantify all of our systematic uncertainties; and we should allow for plenty of investigation of alternative explanations and theories. In observations, we also should be careful about selection effects, incompleteness, and biases. Finally, we should remember that scientists are human and sometimes make mistakes. Scientists are trying to explore and gain knowledge about what’s really happening in the universe, but sometimes other interests (funding, employment, reputation, personalities, conflicts of interest, etc.) play important roles. We must watch out for herding effects and confirmation bias, where we converge and end up agreeing on the incorrect answer. (Historical examples include the optical or electromagnetic ether; the crystalline spheres of medieval astronomy; the humoral theory of medicine; ‘catastrophist’ geology; etc.) Paradigm shifts are rare, but when we do make such a shift, let’s be sure that what we’re transitioning to is actually our currently best paradigm.

[For more on philosophy of science, this anthology is a useful reference, and in particular, I recommend reading work by Imre Lakatos, Paul Feyerabend, Helen Longino, Nancy Cartwright, Bas van Fraassen, Mary Hesse, and David Bloor, who I didn’t have the space to write about here. In addition, others (Ian Hacking, Allan Franklin, Andrew Pickering, Peter Galison) have written about these issues in scientific observations and experimentation. For more on the sociology of science, this webpage seems to contain useful references.]