Ideas are interesting, but people are vastly more so.
Sarah Bakewell has followed her lovely book about Montaigne with an equally lovely book about the existentialist movement. Comparing the books, one can see an obvious theme emerge in Bakewell’s writing: the interest in practical philosophy. Montaigne and the existentialists share the tendency to write about their own lives and, in various ways, to attempt to live out the tenets of their philosophies. This makes Bakewell’s biographical method especially revealing and rewarding, while at the same time adding a subtle, highbrow self-help aspect to her books—life lessons with the imprimatur of big names and fine prose.
Bakewell attempts to tell the story of the existentialist movement from its twentieth-century beginnings (skipping over precursors such as Dostoyevsky and Kierkegaard) to its apparent end, with the deaths of its principle architects. The four main protagonists are Martin Heidegger, Maurice Merleau-Ponty, Simone de Beauvoir, and Jean-Paul Sartre (who, unsurprisingly, is the dominant personality), along with shorter appearances by other thinkers: Husserl, Camus, Raymond Aron, Karl Jaspers, and Simone Weil, to name the most prominent. When you consider the sheer amount of biographical and philosophical material this list represents, you realize the magnitude of the task set before Bakewell, and the consequent skill she demonstrated in producing a readable, elegant, and stimulating book.
I am sorry to say that I have read very little of the writings of the principle actors, with the exception of Heidegger. Bakewell’s account of him mostly confirmed my own experiences with the infuriating metaphysician, especially in his disturbing lack of character and, indeed, of basic humanity. Sartre comes across as far more human, if not exactly more likable. Few people could hear of Sartre’s enormous philosophical, biographical, journalistic, and literary output, over so many years, without feeling a sense of awe. Nevertheless, Sartre’s opinions rarely struck me as measured or reasonable. Though I often mourn the decline of the public intellectual, Sartre’s example gives me pause, for his influence on contemporary politics was not necessarily salubrious. Perhaps it is true that intellectuals, seeking consistency and clarity, are naturally inclined towards extreme positions. Sartre was, in any case, and it led him into some foolish and even reprehensible positions.
By contrast to these two giants, Beauvoir and Merleau-Ponty come off rather well in this story. The former tempered her political opinions with a greater subtlety, thoroughness, and empathy; while the latter lived a quietly productive and happy life, while creating a philosophy that Bakewell argues constitutes the greatest intellectual legacy of the bunch.
Just as Bakewell argued that Montaigne’s writings are newly relevant for his sense of moderation, so she argues that the existentialists are newly relevant for exploring the questions of authenticity and freedom. Not having read most of their work, I cannot comment on this. But what I found most inspiring was their burning desire to think and to write—and to write like mad, for hours each day, in every genre, for decades on end. Though most of this writing was born today to die tomorrow, each one of them produced a magisterial tome for future readers to beat their heads against. I suppose I will have to pick them up sometime soon.
There are few phrases more annoying or more effective than “I told you so.”
This is my second encounter with Thomas Kuhn, and again I emerge deeply impressed. To do justice to an event so multifaceted as the Copernican Revolution a scholar must have a flexible mind; and Kuhn is fully equal to the task. He moves seamlessly from scientific data, to philosophical analysis, to historical context, and then back again. The result is a book that serves as an admirable introduction to the basics of astronomy and a thorough overview of the Copernican Revolution, while raising intriguing questions about the nature of scientific progress.
Kuhn first makes an essential point: that the conceptual schemes of science serve both a logical and a psychological function. Their logical function is to economically organize the data (in this case, the position and movement of heavenly objects); their psychological function is to make people feel at home in the universe. Belief is only necessary for this second function. A scientist can use a conceptual scheme perfectly well without believing that it represents how the universe ‘truly is’; but people have an obvious and, apparently, near-universal need to understand their place in, and relation to, the cosmos. Thus, scientists throughout history have insisted on the truth of their systems, despite the history science being littered with the refuse of abandoned theories (to use Kuhn’s expression). Even if this belief cannot be justified philosophically, however, it does provide a powerful emotional impetus to scientific activity.
Another question Kuhn raises is when and why scientists decide that an old paradigm is unsustainable and a new one is required. For centuries astronomers in the Muslim and Western worlds worked within the basic approach laid down by Ptolemy, hoping that small adjustments could finally remove the slight errors inherent in the system. During this time, the flexibility of the Ptolemaic approach—allowing for fine-tuning in deferents, equants, and epicycles—was seen as one of its strengths. Besides, the Ptolemaic astronomy was fully integrated within the wider Aristotelian science of the age; and this science blended perfectly with common everyday notions. The fact that the Ptolemaic science broke down is attributable as much, or more, to factors external to the science as to those internal to it. Specifically, with the Renaissance came the rediscovery of Neoplatonism, with its emphasis on mathematical harmonies—something absent from Aristotelianism—as well as its strain of sun-worship.
Copernicus was one of those affected by the new current of Neoplatonism; and it is this, Kuhn argues, that ultimately made him dissatisfied with the Ptolemaic system and apt to place the sun at the center of his system. We often hear of science progressing as a result of new experiments and empirical discoveries; but no such novel observation played a role in Copernicus’s innovation. Rather, the source of Copernicus’s rejection of an earth-centered universe was its inability to explain why the planets’ orbits are related to the sun’s. His system answered that question. But this was only an aesthetic improvement. It did not lead to more accurate predictions—the essential task of astronomy—and, indeed, it did not even lead to more efficient calculations. The oft-reproduced image of the Copernican universe, consisting of seven concentric circles, is a simplification; his actual system used dozens of circles and was cumbersome and difficult to use.
But the most puzzling feature of Copernicus’s innovation is that it achieves qualitative simplification at the expense of rendering it completely incompatible with the wider worldview. Aristotelian physics cannot explain why a person would not fly off of a moving earth. And, indeed, the entire cosmological picture, such as that painted so convincingly by Dante, ceases to make sense in a Copernican universe. For centuries people had understood the earth as a midpoint between the fires of hell and the perfect heavens above. Now, hell was only metaphorically “below” and heaven only metaphorically “above.” Besides that, the universe had to be expanded to mystifying proportions; the earth became only a small and unimportant speck in an unimaginably vast space. Strangely, however, Copernicus seemed blind to most of these consequences of his innovation. A specialist concerned only with creating a harmonious system, his attempt to render it physically plausible or theologically palatable is, at best, half-hearted.
This leads to the irony that one of the greatest intellectual revolutions in history started with a man concerned with technical minutiae inaccessible to the vast majority of the public, who had access to no fundamentally new data, whose system was neither more accurate nor more efficient than its predecessor, and whose main concern was qualitative harmoniousness. Copernicus was no radical and had no notion of upsetting the established authority; he himself would likely have been appalled at the Newtonian universe that was the end result of this process.
Yet this simple innovation, once proposed, had ripple effects. Though the earth’s motion was near universally rejected as a fact, its use in a serious astronomical work kept it alive as an option. And this new option could not be laughed away when, in the next generation under Tycho Brahe, better observations and novel phenomena upset the Ptolemaic world order. The heavens could no longer be seen as perfect and unchanging when Brahe proved that supernovae and comets do not exhibit a parallax (as in, they do not to change location when the observer moves), and thus could not be atmospheric phenomena. Further, Brahe’s unprecedentedly accurate observations of the planets were incompatible with any Ptolemaic system. This seems to be one of many cases in the history of science when novel observations followed, rather than preceded, a theoretical innovation.
Granted, this incongruence led Brahe to propose his own earth-centered system, the Tychonic, rather than adopt a sun-centered universe. But this new system used Copernican mathematics, and embodied the Copernican harmonies. In any case it is hard to see how the Tychonic system could ever have been anything but a stopgap, since the jump from Ptolemy to Brahe was scarcely easier than the jump from Ptolemy to Copernicus. Besides, it struck many as dynamically implausible that everything in the universe would orbit the sun except the earth and the moon.
Kepler and Galileo were among those unconvinced by the Tychonic system. The two very different men were both of an independent turn of mind, and their work finally made the Copernican universe unequivocally superior. Kepler particularly made the decisive step with his three laws: that planets orbit in ellipses with the sun at a foci, that they sweep out equal areas in equal times, and that they orbit the sun in a ratio of the 3/2 power (the orbital axis to the orbital time). But in Kepler we find further ironies. Far from the dispassionate lover of truth, Kepler was a Neoplatonic mystic, bursting with occult hypotheses. Many parts of his work strike the modern reader as scarcely more rational than the ravings of a conspiracy theorist. Yet the hard core of Kepler’s astronomical work lifted Copernicanism into a league of its own for accuracy of prediction and efficiency of calculation. If the orbits of the planets were related to the sun in such simple, elegant ways, it was difficult to see how earth could be at the center of it all.
This is my best attempt at summarizing the most salient points of the book. But of course there is far more in here, most of it worthwhile. I particularly enjoyed Kuhn’s chapter on the oft-ignored medieval research into physics, such as the impetus theory in the work of Nicole Oresme. The only weak point of the book was the rather brief epilogue to Copernicus. In particular, I would have appreciated an entire chapter devoted to Newton, since it was his Principia that was, in Kuhn’s phrase, the “capstone” of the revolution. But on the whole I think this is a superlative book, serious yet accessible, informative while brief. Kuhn captures the reality of scientific progress, which is far less neat that we may like to believe. Most striking is how a revolution which was guided by many extra-logical considerations—the Neoplatonic belief in celestial harmonies, the desire for mathematical elegance, the weakening of the religious worldview, the need to feel at home in the universe—fueled a process which, taken as a whole, resulted in a science definitively better than the Ptolemaic system it replaced.
Kuhn makes no mistake about this. Here is what the reputed relativist has to say:
The last two and one-half centuries have proved that the conception of the universe which emerged from the Revolution was a far more powerful intellectual tool than the universe of Aristotle and Ptolemy. The scientific cosmology evolved by seventeenth-century scientists and the concepts of space, force, and matter that underlay it, accounted for both celestial and terrestrial motions with a precision undreamed of in antiquity. In addition, they guided many novel and immensely fruitful research programs, disclosing a host of previously unsuspected natural phenomena and revealing order in fields of experience that had been intractable to men governed by the ancient world view.
Alexander von Humboldt was a remarkable man. Simultaneously a savant and an explorer, he knew everyone, studied everything, and did his best to travel everywhere. Andrea Wulf brings together the many seemingly divergent worlds that he bridged: the worlds of Thomas Jefferson, Simón Bolívar, Napoleon, Goethe, Charles Darwin, and even Isambard Kingdom Brunel. He left his fingerprints on the worlds of science, literature, art, and even politics. Yet today he is (or was, before Wulf) a fairly obscure figure in the English-speaking world.
Thus this book is not simply a biography, but an attempt at rehabilitation. Wulf wishes to restore Humboldt to his place of honor; and she does this by arguing that his influence has been fundamental and pervasive. But before she can deal with Humboldt’s reputation, she must first narrate the scientist’s own coming of age. Humboldt was one of these figures with seemingly boundless energy, who threw himself into his work with complete abandon. We watch the young Humboldt as he struggles with, and finally throws off, the expectations of his upbringing, and then dashes away to South America. Once he embarks on his voyage, it does not take a strong writer—which Wulf is—to make his story exciting. Humboldt’s own travelogues were bestsellers.
Humboldt emerges from his travels with a concept of nature which, Wulf argues, was revolutionary and which became extremely influential. Wulf identifies three new elements of Humboldt’s approach to nature: First, that nature cannot be understood without both the scientific and the poetic eye; analysis and sentiment are necessary to do justice to the natural world. Second, that the living world must be understood as a gestalt, with organisms depending on one another in an intimate set of relationships that boggles the intellect. And third, that scientists must think on a global scale if they wish to understand the complex interactions between plants, animals, and climates.
This is the meat of the book. Yet it is here that I began to shift from enchantment to disappointment. For Wulf does not do nearly enough work to convince the skeptical reader that Humboldt’s view of nature was so entirely new. I would have appreciated far more background on previous conceptualizations of the natural world. Without this, it is hard to tell where Humboldt was innovative. Further, Wulf is always rather vague with Humboldt’s actual scientific contributions. She elects to keep the narrative pace driving forward, which doubtless helped her sales; yet I would have appreciated an explanation of Humboldt’s thought in more detail, with a good deal more quoting of the man.
Conversely, Wulf could have greatly reduced the space devoted to the men Humboldt influenced. She has individual chapters for John Muir, Henry David Thoreau, Charles Darwin, George Perkins Marsh, and Ernst Haeckel—space that she uses as opportunities to prove her thesis that Humboldt’s writings were fundamental to their success. But I found the biographical detail for these men excessive, and her point overstated. She makes it seem as if these men owed their accomplishments—if not wholly, at least in large part—to Humboldt’s influence. But you cannot measure influence, and you cannot prove a counterfactual (what would they have done without Humboldt?). In any case, the point is entirely abstract without a more careful discussion of Humboldt’s ideas; lacking that, it is not possible to say where his influence begins or ends.
By now I am convinced that Humboldt was an important and compelling figure in the history of science. But I am far from convinced that his late obscurity was a mere result of anti-German prejudice caused by the two World Wars, as Wulf claims in the Epilogue. Too many other German scientists and philosophers remained famous. Rather, I think Humboldt may have fallen into obscurity because it is difficult to do justice to the nature of his contribution. Unlike Darwin, he did not originate any major scientific theory that could unify a great many phenomena under a simple explanation. Humboldt’s major contributions seems to be perspectival: seeing nature as complex yet whole, as godless yet beautiful, as vast and inhuman yet spiritually refreshing. And it is difficult to work that into a textbook.
But sound, as I have said above, only travels 180 toises in the same time of one second: hence the velocity of light is more than six hundred thousand times greater than that of sound.
This little treatise is included in volume 34 of the Great Books of the Western World, which I used to read Newton’s Principia and his Opticks. In this edition the Treatise comes out to about 50 pages, so I decided it was worth combing through. Christiaan Huygens is one of the relatively lesser known figures of the scientific revolution. But even a brief acquaintance with his life and work is enough to convince one that he was a thinker of gigantic proportion, in a league with Descartes and Leibniz. His work in mechanics prefigured Newton’s laws, and his detailed understanding of the physics of pendulums (building from Galileo’s work) allowed him to invent the pendulum clock. His knowledge of optics also improved the technology of telescope lenses, which in turn allowed him to describe the rings of Saturn and discover the first of Saturn’s moons, Titan.
Apart from all this, Huygens was the progenitor of the wave theory of light. This is in contrast with the corpuscular theory of light (in which light is conceived of as little particles), put forward 14 years later in Isaac Newton’s Opticks. Newton’s theory quickly became more popular, partially because of its inherent strength, and partially because it was Isaac Newton who proposed it. But Huygens’s wave theory was revived and seemingly confirmed in the 19th century by Thomas Young and Augustin-Jean Fresnel.
Essentially, Huygens’s idea was to use sound as an analogy for light. Just as sound consists of longitudinal waves (vibrating in the direction they travel) propagated by air, so light must consist of much faster waves propagated by some other, finer medium, which Huygens calls the ether. He conceives of a luminous object, such as a burning coal, as emitting circular waves at every point in its surface, spreading in every direction throughout a space.
Like Newton, Huygens was aware of Ole Rømer’s calculation of the speed of light. It had long been debated whether light is instantaneous or merely moves very quickly. Aristotle rejected the second option, thinking it inconceivable that something could move so fast. Little progress had been made since then, because making a determination of light’s speed presents serious challenges: not only is light several orders of magnitude faster than anything in our experience, but since light is the fastest thing there is, and the bearer of our information, we have nothing to measure it against.
This changed once astronomers began measuring the movement of the Jovian moons. Specifically, the moon Io is eclipsed by Jupiter every 42.5 hours; but as Rømer measured this cycle at different points in the year, he noticed that it varied somewhat. Realizing that this likely wasn’t due to the moon’s orbit itself, he hypothesized that it was caused by the varying distance of Earth to Jupiter, and he used this as the basis for the first roughly accurate calculation of the speed of light. Newton and Huygens both accepted the principle and refined the results.
Huygens gets through his wave theory, reflection, and refraction fairly quickly; and in fact the bulk of this book is dedicated to an analysis of Icelandic spar—or, as Huygens calls it, “The Strange Refraction of Icelandic Crystal.” This is a type of crystal that is distinctive for its birefringence, which means that it refracts light of different polarizations at different angles, causing a kind of double image to appear through the crystal. Huygens delves into a detailed geometrical analysis of the crystal, which I admit I could not follow in the least; nevertheless, the defining property of polarization eludes him, since to understand it one must conceive of light as a transverse, not a longitudinal, wave (that is, unlike a sound wave, which cannot be polarized). In the end, he leaves this puzzling property of the crystal for future scientists, but not without laying the groundwork of observation and theory that we still rely upon.
All together, this little treatise is a deeply impressive work of science: combining sophisticated mathematical modeling with careful experimentation to reach surprising new conclusions. Huygens illustrates perfectly the rare mix of gifts that a scientist must have in order to be successful: a sharp logical mind, careful attention to detail, and a creative imagination. The world is full of those with only one or two of these qualities—brilliant mathematicians with no interest in the real world, obsessive recorders and cataloguers with no imagination, brilliant artists with no gift for logic—but it takes the combination to make a scientist of the caliber of Huygens.
In manifold ways 2018 was an excellent year. I traveled to places I never expected to see, I read books that had long been on my list, and in general I had a great time. In fact, I did so many things that I have a lot of catching up to do on this blog. And my major resolution is to put even more effort into my writing this year.
So, without further ago, here is an incomplete list of the places I visited that I still need to write about:
One of my resolutions is to brush up on math. I hope, first, to read about Greek mathematics, and even to see if I can penetrate a few works of Archimedes (highly unlikely). I also have a calculus textbook that I hope to use to revive my atrophying abilities (equally improbable).
Meanwhile, I have typically immoderate and unrealistic reading goals. Some hefty existentialist tomes have been weighing me down: books by Kierkegaard, Sartre, and Husserl, to name just three. There are also many classic French writers I have yet to read: Pascal, Balzac, Stendhal, Le Rouchefoucault… And then there are some ponderous and interminable history books that I are in my sights.
I should stop myself here, since I will have to eat all of these words. One thing I can be certain of, though, is that I will neither diet nor exercise.