A Forest of Symbols : Symbolism and Philosophy

“I always had a soft spot for artists and writers labeled symbolists,” Andrei Pop tells us, “if only because they were often picked on.” Indeed, he explains, they were unjustly labeled incomprehensible neurotics or egoists, anarchists or decadents — the latter even becoming a popular name for the movement. For Pop, an associate professor of art history at the University of Chicago and a member of its Committee on Social Thought, symbolist practices are crucial to understanding the genesis of modern art. Now an intellectual assumption across many disciplines, symbolism, Pop affirms in his new book “A Forest of Symbols,” was a consequence of the radical rethinking of the nature of the symbol in the late 19th century. His book provides a rich and unprecedented examination of this historical period, and a unique framework for rethinking the emergence of non-referential models of perception and for understanding the modernization of how various forms of knowledge can be represented.

Like many of the titles we at Zone Books are proud to have published in recent years — Christopher Heuer’s “Into the White,” Mitchell Merback’s “Perfection’s Therapy,” and Amy Powell’s “Depositions,” among them — Pop’s vibrant book is driven by crucial questions internal to art history but which, in their realization, are fundamentally transdisciplinary in extraordinarily creative ways. This creativity is well-reflected in the far-reaching interview featured below, in which Pop discusses, among other topics, what drew him to symbolism, the potential symbols have to communicate a common visual language, and the outsized influence of Edgar Allan Poe.

Zone Books: “A forest” seems a fittingly symbolic choice for the title. How did you decide upon it?

Andrei Pop: Credit goes to the great French poet Baudelaire, who wrote that “Man passes through forests of symbols which watch him with familiar gazes.” This reminds me of a jungle with stone idols glaring through the foliage, mysterious but also a bit silly — like a Tintin comic. But a forest is so much more: not just a thing or place but a world for plants and animals and people, who use it for food, shelter, resources — in other words, they coexist uneasily within it. And everything the humans do, practical or theoretical, they represent in pictures or words or other symbols: so symbols are our forest, and we even overlay nonhuman nature, whether forest or outer space, with symbols to bring it closer to us (the Moon, the Sun, the Milky Way). A Forest of Symbols then is a symbol full of symbols: the very theme of the book. But the title didn’t come easy! I only picked it after being struck by all the forest symbolism I used in the book, like the common phrase of ‘not seeing the forest for the trees’. Finally, there is a small but significant difference between Baudelaire’s phrase and mine: his forests are many, mine just one, “a forest” linking art and science as symbol-making activities.

ZB: What drew you to questions of symbolism?

AP: I always had a soft spot for artists and writers labeled symbolists, if only because they were often picked on. They were supposedly overblown or overwrought or incomprehensible, they ignored nature, dabbled in the dark arts or art for art’s sake, were neurotics or egoists or anarchists or decadents — the last was even a popular name for the whole movement. Yet what these criticisms missed is the humor and the intelligence of this art, which often turned its razor wit against itself and its makers: the artist’s futile attempts to represent the world for other human beings. Then I was struck by what seemed a pure linguistic coincidence: the fact that mathematicians of the era spoke of “symbolism” too, e.g., the mathematician-philosopher Whitehead even wrote a book with this title. They did not mean art, but just the technical notations they used to express logical proofs. It turned out, on closer investigations, that these two apparently opposite practices both involved getting unreliable, subjective, self-centered human minds to pay attention to subtle nuances of drawn or printed or otherwise inscribed figures, for the purposes of coming to understand each other and recognize objective truths they could share. I was hooked.

ZB: Several artists, writers, philosophers, and mathematicians appear throughout your discussion: including Edgar Allan Poe, Stéphane Mallarmé, and Ludwig Wittgenstein. How did you choose which figures to discuss?

AP: I wish I could say it took great originality to collect these people, but the artists, whether poets or painters, just couldn’t shut up about Poe. And they were right! Just like Bart Simpson and a lot of general readers, I’ve always loved Poe, but did not realize what a systematic thinker he is. He explained with great philosophical clarity just how he intended to get the personal, incalculable effects his stories and poems like “The Raven” have on us. This theoretical bottom to Poe, but also to his translator Mallarmé and his friend the painter Manet, made them akin to my mind to the great turn-of-the-century philosophers Frege and Wittgenstein, who wrestled with how limited animal minds with a rough and ready language can know eternal truths of logic and mathematics. These thinkers in turn were friends in real life and connected in the history of philosophy. My one originality, which I think justified, has been to bring them together: Poe and Frege, Wittgenstein and Mallarmé. It is their shared ideas and the common difficulties they wrestled with, such as the possibility (or impossibility) of a private language, that to my mind justifies the combination. It might also allow us, having the benefit of their insights, to see farther than these geniuses.

ZB: How did you find and curate the illustrations for the book?

AP: Some of them have been with me since student days — especially the Manet lithographs of Poe’s Raven, which I stumbled across in the Fogg Museum print study room while studying for grad exams at Harvard: a scary rite of passage where you could be shown any object in the enormous collection without being told what it is. The Manets didn’t come up, but a seed of curiosity was planted. Another work, Van Gogh’s otherworldly green portrait of his mother, painted from a black and white photograph by the homesick son, is one of the first artworks I discovered on starting high school in Southern California in the 1990s. Others, like Seurat’s Grande Jatte and the chest, painted and carved by Gauguin, I’ve seen repeatedly over the last few years at the Art Institute of Chicago. Many I found in books, and are only to be found there, being book illustrations. One particular drawing was known to scholars over the last quarter-century only in reproduction. I finally tracked down the original just as the book was being printed this summer 2019. So it is quite a cast of characters, from familiar friends to chance acquaintances. They belonged in the book if I could explain what drew me to them, and what made them speak to each other. I have also given each a little commentary on the page where they are reproduced, in addition to the main text. They deserve the second look!

ZB: At one point, you outline that there are aesthetic, scientific, political, and other signs. What are the other kinds of signs might one encounter?

AP: There may not be “countless uses of language” as Wittgenstein thought, but indefinitely many sign systems: as many as activities requiring coordination. Every sport has its gestures and slogans, there are lovers’ hearts carved into trees, rituals and regalia for every priesthood and profession. A whaler and a thief have their own patois, and possibly worldview: modern stories like Moby Dick show us that. Music is fascinating because its signs are often implicit. Key signatures can convey mood, like the bleak D minor heralding Mozart’s stone guest, who drags Don Giovanni to hell. I have always wondered: are keys really signs to “be read” correctly, or just sound patterns to which people respond freely? One may ask the same about animal calls: stomping tails to indicate danger may be a sign, but what about pheromones that animals and even plants release unwittingly? The American logician Peirce, who makes a cameo in my book, was fascinated by natural signs, like smoke for fire. (He was doubtless acquainted with Native American communication systems). In the book I focus on symbols, which are signs intended to be recognized as intentionally made to be such. I’ll end with an odd one: martial arts. I practiced judo a lifetime ago, and knew the names for the grabbing at each other’s kimonos and trying to trip each other up that we did. These were ordinary Japanese words, but our fumbling moves were themselves signs of the elegant modes of flooring the opponent to whose ideal beauty we aspired in vain.

ZB: It seems that symbols have the potential to communicate a common visual language, but also to be overlooked, or misunderstood. How do you see the artists of the 19th century grappling with that issue?

AP: Enlightenment thinkers, confronted with classical Chinese and ancient Egyptian writing, thought pictures could be a new universal language, imparting wisdom impossible to misinterpret. Alas, two centuries of false starts with hieroglyphs taught them, by the end of the 19th century, that pictorial language, being immediate and intuitive, can give rise to the wildest misunderstanding. That has its bright side too: one doesn’t misunderstand prosaic interactions like paying for groceries. It is with singular, puzzling, dark or dazzling things or happenings that we have a hard time saying what they are. In my book I quote some classic vitriol, such as the painter-poet Dante Gabriel Rossetti, a visionary artist in his own right, exclaiming that Manet’s Raven illustrations are only fit for insane asylums. The old art critics were interested in such outbursts because they showed what prejudices modern innovators had to overcome. The Marxist critics on the other hand think they stem from class tensions. Both might be right: but there are more immediate causes of misunderstanding, from the state of one’s own body to the education one brings to the artwork. The artists in my book were used to being called incomprehensible: they did not despair, but patiently asked that viewers look closer, and think longer. It’s good advice for us too, as distractions and the demands on our time have multiplied.

ZB: Going further, you discuss the slippage between private and public meaning. Is there something that viewers of art can do to recognize public meaning more often?

AP: The 20th century, from Wittgenstein to various technocratic states, was haunted by the idea that all meaning is public and so all our thinking ought to be as well. In art, this amounts to going into the gallery and doing long division out loud: the only reason we’d speak is to show off our facility doing something trivial. This has been the ideal of some old academic art institutions, but fortunately art is too unpredictable to achieve it. The opposite extreme, a purely interior world of unutterable feelings, is unfortunately closer to the cliché of museum as temple: silent people looking pained, furrowing their brow at artworks, grunting now and then. Much better, both for personal enjoyment and for any kind of political, moral, or scientific insight, is a balance between the experiences we have as individuals and shared content — the plot of a story, the sitter of a portrait, the mode of representation or the use of material, which points to historical context. The private too can be given its due, without being remorselessly made public: a parent’s pain for a deceased child, or the artist’s commitment to a cause, which thankfully we need not share to appreciate. One might say with Freud that “I (the ego) will be where It (the unconscious) was”, that is, become self-aware. But I prefer to think we can make articulate in dialogue what we both see as well as the marvelous fact that we do not both see everything one of us sees.

There may not be “countless uses of language” as Ludwig Wittgenstein thought, but indefinitely many sign systems: as many as activities requiring coordination. Image: Wikimedia Commons

ZB: You write that “the logical content of pictures is richer than generally supposed.” How can one learn to identify the logical content?

AP: “Logical” here doesn’t mean syllogisms or standard notation out of a first-year college course. By those standards, pictures are judged logically boneless, flabby, formless; but so is much language. Take the simple utterance “See Spot run”. Nothing follows from it syllogistically. Yet there is logical content: the scaffolding on which its meaning is built. The request or command to the hearer to perceive something, the claim that what will be seen is an action of the subject Spot, perhaps even the suggestion, built on Anglophone traditions, that Spot is a dog. Here we see how the logical blends into the factual, but there are facts about the world that are not logical: whether there is a Spot, who or what that is, and so on. Likewise, in pictures, such matters as the causal means of their making (mechanical, optical, by hand?), whether they belong to the past or to timeless imagination, whether they represent sentient beings, and those beings are meant to be doing or thinking something, or showing awareness of the presence of spectators: all this belongs to the scaffolding of meaning, which historical detail fills out. There is no algorithm for figuring out what is logically implied in an image and what we need to know about the world to grasp it; it is a mutually informing process. The payoff to perceiving what is there logically is that we are more likely to look in the right place for the facts that bring the picture to momentary life.

ZB: Do symbols help people to see an artwork in the way that the artist intended it?

AP: Writing this book, I grew fascinated and finally impatient with all the catchy terms for what is really the same thing: sign, emblem, allegory, Leitmotiv, Ur-form, Gestalt, schema, and of course symbol and all its variations. What is important about symbolist art — and science, which is not usually called symbolist, but should be — is that it regards symbols as purposely devised to function as such. An artificial, that is a human-made object, be it paint or sound or ink on paper, stands for some reality, abstract and conceptual like Number or Truth or concrete and dusty like a bone or a tree. The point of the symbol is to not confuse it with the thing symbolized. Even if you take a tree to symbolize another, say a bonsai for a mighty oak, you do not conflate the two. The artwork describes reality at a distance, and it is good to know the distance. This is already a step along the road to understanding art rightly, that is self-reflectively and intelligently. Whether it is also what the artist intended depends on the artist — was the artist careful and reflective? It is possible to notice something in an artwork that the artist totally missed. But the greatest artists invest their work richly with meaning, whether they are aware of it or not. So knowing the art helps up enormously to know the people. It is the closest we will ever get to reading the minds of those long gone.

ZB: You write that “Color is, as much as pain, a paradigm case of the private.” Yet, today, marketing and psychological studies try to find common, if not objective, effects of color. Is color still private? Would one’s experience of color and its symbolism have been more private in the 19th century?

AP: Advertising wouldn’t earn its keep if it didn’t explore our hopes and fears — as do doctors for nobler purposes. I would say pain is analogous: it is colonized today by states seeking ways to torture without hurting the body (waterboarding?) and pharmaceutical companies peddling opiates, but also to cure, and if not, to understand the experience of those living in pain. These developments start in the symbolist 19th century, prior to which little was known about how the eye processes light, not to mention the liquor-and-a-board-to-bite-on approach to anesthesia. So it certainly seems as if the lonely part of our minds is shrinking. But: to this we must always add, “approximately.” An adman or dietician might know that this or that hue will make you hungry or kill your appetite: they still don’t see what you see when you have that measurable public reaction. In science fiction, authors imagine telepathy or ‘feely’-machines. The hero of William Gibson’s Neuromancer feels the excruciating pain of the heroine when she breaks her leg. Frege foresaw this scenario a century ago and replied: is it the same pain, or a different one beamed now into a second person? He thought there could be no right answer, unless we were both people at once. So there will always be metaphysically private experiences, no matter how intrusive Big Brother becomes. The challenge is how to make them count: like aesthetes circa 1900, many of us want transformative experiences that also matter to the world we inhabit.

ZB: Can you say what you’re working on next?

AP: I think it might already be obvious from the last answer: science fiction! Like symbolism, it explores the farthest imaginable reaches of human — and not just human — experience, but it does so often in a naïve, breakneck fashion that is a lot of fun after the subtleties of Manet or Frege. And if symbolism is inseparable from my experience of growing up intellectually, science fiction has been with me even longer: as long as I could read or write, and certainly before I spoke the American English that even the most exotic Hollywood aliens favor. It stayed with me too. Today literary scholars look to this genre for answers, or at least questions about our uncertain future: climate change, human migration to the stars, a world of radical genetic and computer science. That is important, but for me it is also exciting to attend to earthy and disposable materials like pulp paperbacks and magazines, lurid space films from the dawn of cinema and today’s slick video games, so different from the fastidious elegance of symbolism. Although there is symbolist science fiction too: not for nothing was Poe a pioneer of the genre. His revived Mummy observes that they had Progress in its time too, but it never progressed. I find what is absurd and funny as important as what is sad and portentous, and only together do they capture our experience of that part of reality that does not yet exist — the Future.

Zone Books is an independent nonprofit publishing house founded in 1985. Zone Books are edited by Jonathan Crary, Michel Feher, Hal Foster, and Ramona Naddaff, and designed by Bruce Mau and Julie Fry. They are distributed by the MIT Press.

A Forest of Symbols: In Conversation With Andrei Pop.  By: Zone Books/The Editors.  The MIT Press Reader , December 9, 2019.

On the face of it, art historian Andrei Pop, in his latest book, A Forest of Symbols: Art, Science and Truth in the Long Nineteenth Century (Zone Books, 2019), sets out to achieve something rather concrete—a reevaluation of the French symbolist movement in art—and yet the reader soon becomes aware that much more is at stake, as Pop weaves together art history with an account of early analytic philosophy to raise questions about the very nature of truth and human ways of meaning-making in artistic and scientific practice, which are further explored in this interview with David Kretz.

DK : A Forest of Symbols: Art, Science, and Truth in the Long Nineteenth Century begins by characterizing a type of mid-19th-century reductionism about the self and the mental that finds expression, for example, in Ernst Mach’s psychologistic philosophy and impressionist painting, which, roughly speaking, presents the viewer with sensations of color pigments rather than with objects. You then establish a surprising parallel between two counter-reactions to this Zeitgeist: symbolist art and early analytic philosophy, especially Frege and the Wittgenstein of the Tractatus. Can you sketch the parallel in their responses for us?

AP : The predominance of positivism and various forms of mechanistic philosophy and science, including physiological psychology, was no ideological conspiracy but a result of real progress: the invention of analytic chemistry, the refinement of celestial mechanics, and the rapid strides in comparative anatomy, microbiology, and the rest, crowned as we still think by Darwinian evolutionary theory. To say nothing of practical gains from pasteurization to electricity. This materialist front faltered a little when confronting the mind and subjectivity, but here too advances were legion: from the study of the eye and physiologic color to the psychology of counting and their manifold applications, from calculators to color printing, early motion pictures, and, yes, realist and impressionist painting. These art practices, of course, were not always understood as reductive, but insofar as they were—as they answered to the decree of “paint only what you see”—they fit the positivist lockstep.

Only they also produced weirdness: what an impressionist ‘saw’, made up as it was of blocky saturated brushstrokes, differed markedly from what anyone else saw, live or through a camera. So the act of translating vision to canvas produced an effect different in kind. At the same time, positivism was of little help in the foundations of arithmetic, or physics, where explaining natural law mechanistically and psychologically (a tendency called “psychologism” on the model of scientism—taking psychology beyond its field of application) led to theories of numbers as consensual hallucinations, or meaningless counters in a game. This self-undermining nature of positivism—its search for verification leading always to unstable mental states that could deceive the verifier—naturally led to revolt among ambitious scientists from Boltzmann to Cantor. The revolts tended to assert the reality of things unseen and strictly unseeable: whether infinite sets (Bolzano) or irrational numbers (Weierstrass) or both of these (Dedekind, Cantor, Frege). This is a reformed Platonism, because it doesn’t point us to the perfect Bed in the sky, but to what is necessary for there to be anything at all—the laws of arithmetic describe any possible universe. They certainly underlie the mathematical natural science on which positivism relied while undermining it.

It is perhaps surprising then that the scientific revolt against equating truth with the perceptible or verifiable, which issued in mathematical logic and philosophy of language that you call “early analytic philosophy”, also made room for domains inaccessible to it, what it called the subjective realm, which stretched from color perception and proprioception to poetic nuance to aesthetic judgment. If we identify the later tradition with the elimination of subjectivity and a nearly algorithmic commitment to the application of logic to philosophical problems, we may, ironically, regard Frege and the young Russell and Wittgenstein as backward Romantics, because they sought to delimit objective sense and laws from realms of radical subjectivity that separate each mind from each other: the very notion of private language, which the older Wittgenstein violently rejected. The philosophical point of this book is to show that the objective requires the subjective as a foil if it is to play the scientific role late nineteenth-century philosophers assigned to it, not to mention to become accessible through our perceptual apparatus in new kinds of mathematical and logical symbolism. As for the symbolist artists, they frankly acknowledged that the mind contributes as much as the hand in reproducing reality, so that continuous color and contour, which impressionism and the opticians had rejected as found nowhere in nature, reappear as signs of our subjective activity as perceivers as much as our logical activity organizing percepts into objects. The category of the image serves as a useful beacon, joining theoretical speculation to plastic art: it is structured sense itself, distinct from and mediating between the concrete things embodying it and whatever else, concrete or abstract, they stand for or refer to. But once one has noticed the affinity between the artistic and philosophical project, there is no reason to leave out photographers, realist painters, or romantic poets like Poe, when one finds them engaged in a project of exploring the interface between the logically objective, or public world, and the private, subjective worlds which Heraclitus already said we each possess.

DK : You agree with historians of science like Lorraine Daston and Peter Galison that there is an artistic aspect to scientific practices of observation and documentation, for example, but want to also claim the inverse: that artworks are, in a sense, truth-apt and logical. Truth in art, moreover, on your view lies not so much in its power to disclose a world (Heidegger, Gadamer). Rather your concept of truth in art seems to follow along representationalist lines: Frege and the early Wittgenstein. Could you tell us more about your understanding of truth—in art, in science? Are they the same? Is truth in art the same as meaningfulness?

AP : The opposition between disclosive and representationalist accounts of truth requires some scrutiny. I take it by the latter you have in mind the view that sentences or images build up models of reality, which we compare with their referent and judge to be true in case the representation corresponds to reality. Frege in fact denied that such a view is generally applicable to pictures—as he pointed out, we would only call a picture of Cologne Cathedral “true” in this sense if we appended the sentence “the cathedral looks like this”, so that what we are really judging true is the sentence. But then he went further and pointed out that the correspondence theory doesn’t explain truth in language either! For if you ask just what makes this sentence correspond to reality, and I provide an answer, you can still ask whether the answer is true, which on the correspondence theory would lead to asking for another object of correspondence (not of the sentence, but of the sentence asserting the truth of the sentence), and thus a vicious regress. So correspondence will not explain truth in general: but it certainly plays a role in much everyday language and imagery, from ID cards to IOUs.

So it won’t do to dismiss representation altogether and insist on elevated uses of “world-disclosing” language and images: it matters whether I owe you or you owe me a sum of money, just as it should matter to the disclosing of a peasant world whether, say, a pair of boots painted by Van Gogh belonged (are painted as belonging) to a peasant woman or not. What matters still has to do with the language or the image: these are logically articulated, which needn’t mean reducible to language. What it does mean is: properly interpreted, it is responsive to true or false propositions about it. This is how a picture differs from the object which is its bearer, as it differs from a stone or a leaf, which are neither meaningful nor potentially true or false, though we can say meaningful, true or false things about them. As for the worry that pictures allow for multiple plausible interpretations, that doesn’t differentiate them from language qualitatively, only quantitatively. A picture might seem awfully ambiguous about, say, the intentions of the person it portrays, but it is merely compatible with several different ones. In turn, a sentence describing a face, as Lessing noticed, is endlessly more ambiguous than even a crude visual image of that face. Logically articulated, then, in every domain, means something like this: the object would mean different things if it were structured otherwise.

Likewise, context matters: language abounds in indexical expressions whose full significance (as opposed to linguistic meaning) depends on who is speaking and listening, and the sense of images may depend on assumptions about who is looking, what goes on beyond the frame of the picture, and so on. This is why I like to say that a historian may not be a Platonist, but a Platonist must be a historian: you never reach mind-independent meaning from a historical artifact unless you account for specific human conventions and acts. As for truth, that is once again a further step: it is not objects as such, but the thoughts they provoke, which are true or false. The only guaranteed truths are the tautologies held in such suspicion by Wittgenstein—which are perfectly respectable logical truths, true solely due to their structure (the same goes for contradictions, which are necessarily false). As for other thoughts, their truth and falsity depends not so much on correspondence to fact (which, inconveniently, tends to ape the representational content of the thought), but on what they really mean. Again artifact and world, structure and context interlock, while remaining very much distinct.

And that is why images, and not just texts or scientific sentences, may be logically articulate: it’s because they are interesting, eventful. The Nelson Goodman line, according to which pictures are just analog color gradients with no structure, is as implausible as Heidegger’s speculations on peasant shoes, which he claims are accessible only in looking at a Van Gogh painting, but which in fact can only be had by reading Heidegger. In order for this kind of art theory to reestablish contact with ordinary acts of looking, and with communication between lookers, and their other intellectual activities (including science), logical structure has to be recognized wherever it is found. It is naturally rather unevenly distributed among meaningful artifacts (perspectival pictures may be dreadful at tense, but they are far better than sentences at describing spaces, and both are terrible at clarifying inferences). We also have to recognize and respect the incommunicable aspect of each subject’s experience, which we can sense rather than verify and which I suspect is what drives the world-disclosing philosophers to their premature attempts at disclosure.

DK : Is there anything that would make an artwork logically inarticulate? Would you rule out the possibility of interesting, eventful nonsense?

AP : I rule out “nonsense” understood as “no sense”, a degree zero of sense: the nonsense poems of Lear, Carroll, dada, medieval monks, etc. are in fact full of tidbits of sense, arranged less than sentence-wise (or even word-wise at times). So the “may be” above applies to the degree of coherence a particular artwork aspires to. A monochrome may well occupy a monistic logical space akin to David Chalmers’ fantastic “consciousness of a thermostat”. If so it is quite dull, perhaps inarticulate by our usual standards, but never unintelligible or senseless in a pure way. Poésie concrète, doodles, automatic writing are telic activities too, with a minimal sense that is requisite to being an interesting representation. Of course, a fossil or a blank wall may be interesting, but not as representation: only as a natural object about which questions may be asked.

DK : How does your understanding of these larger metaphysical and epistemological issues inflect your own methodology as a historian? What do you think art historians should learn from philosophy—and philosophers from (art) historians?

AP : I more than once heard a celebrated philosopher say that his only method is to never say anything that is obviously false. One could do worse! The use of external “theory” in art history once had a dogmatic cast—the writer “knows” that Marxism or Lacanian psychoanalysis or structural linguistics is right, and rearranges art, or rather the extant writings on it, in accordance with this certainty. The old (“classical”) Germanophone art historians by contrast had some philosophical training (generally neo-Kantian), which they did not flaunt, instead inventing terms like Kunstwollen (‘art-willing’), Pathosformel (‘pathos formula’) or symbolische Form (this one due to a philosopher, Ernst Cassirer) to do their philosophizing, still in a broad generalizing vein, but generally asserting a continuity or change over time in how concrete objects embodied these more abstract patterns or schemata. I hope I have learned some lessons from both traditions: to think on our feet when the form of artifacts is meaningful and to look outside them when artifacts reach into the world. Still, art historians must learn not just philosophical theories, but some habits of mind philosophers take for granted (notably analytic philosophers, whom too few of us read, but above all the great philosophical minds, wherever those occur): not to adopt any position because they think it’s right or will elicit admiration without understanding it, but to think for themselves, accepting only what on their best efforts they regard as the truth. This, of course, need not involve certainty, but includes possibilities and hypotheses and the most plausible conclusions.

Can philosophers in turn learn anything from art historians? Well, besides learning what not to do (in the bad case), most art history, and certainly art history at its best, abounds in careful and explicit observation of meaningful artifacts, from all known human cultures and epochs: I think it does so in a way that if properly taken up could challenge the philosophy of mind, of language (which really should be a branch of a larger philosophy of meaning), and of logic and science. Art history isn’t just interesting to aestheticians. Questions ranging from the compositionality of semantics to the nature of things can be elucidated, if not definitively answered, by closer attention to art and artifacts. Not that this will involve taking anything art historians say at face value, but most of what philosophers think about the limits of thought, discursive language and the expressible, would benefit from an acquaintance with a wider range of meaning-making tools. Knowing symbolic logic helps, but so do comics or sculpture or opera! I am just as bad, I have no clue what to make of key signatures and chord changes in music, which can be instruments of thought, as much as any syllogism or perspectival projection. The key to wisdom, I’d agree with Socrates, is knowing that we don’t know. That is something art historians and philosophers have in common with each other—and with everyone else.

Andrei Pop is a professor in the Committee on Social Thought and the Department of Art History at the University of Chicago. Previously, he has taught eighteenth- and nineteenth-century art history and aesthetics at the Universities of Basel and Vienna

David Kretz is a Ph.D. student in the Department of Germanic Studies and the Committee on Social Thought at the University of Chicago. His current project contrasts poets and translators as complementary paradigms of historical agency in times of crisis

French Symbolism and the Origins of Analytic Philosophy. By David Kretz.  Journal of the History of Ideas Blog, December 16, 2019.

Zone Books

Synesthesia, Literature and Art

The use of drugs is often associated with the consciousness-expanding experiences and heightened sensibility described in religious revelations and visions of utopia. But does that mean all users of hallucinogenic drugs become synesthetes, able to perceive uncommon collaborations of several senses at once? The effects of depressant, stimulant, and hallucinogenic drugs on human perception and thinking is well-studied, as evidenced by the large volume of publications on the subject. Browsing through this literature, one finds references to drug-induced synesthesia in two chambers of the library: the science and literature rooms.

In the literature room I followed with delight the tracks of poets and novelists as they took their perceptual experiments to the edges of human experience. After reading wild descriptions by poets proclaiming the merits of their drug-induced synesthesia, I studied the pharmacology and neurology of the same experiences and compared notes. One thing became immediately clear: There is, without a doubt, a special relationship between drugs and synesthesia. But that relationship turns out to be quite different from what I expected.

In 18th-century England, opium was considered a normal medicine and was used in much the same way that people use aspirin today: Opium was considered a good remedy for pain, fatigue, and depression and could be obtained at the local shop. It was also the drug of choice for dealing with sleep difficulties. Several English writers and poets of the Romantic period wrote about their opium experiences, including Thomas De Quincey, Samuel Taylor Coleridge, John Keats, George Crabbe, and Francis Thompson. Their descriptions sometimes include visions that remind me of contemporary reports by synesthetes. For instance, the poet and opium addict Francis Thompson noted on one occasion that he saw the sun rise “with a clash of cymbals”; on another occasion, he described how “tunes rose in twirls of gold” when “light through the petals of a buttercup clanged like a beaten gong.” He also heard “the enameled tone of shallow flute, and the furry richness of clarinet.”

Many of these poets romanticized the virtues of taking opium. Samuel Taylor Coleridge, for one, proclaimed that his poem “Kubla Khan” was composed in a flush of opium-induced inspiration; when he woke up, all he had to do was write it down.

Thomas De Quincey distinguished himself by studying the effects of his opium intake, which he drank in the form of laudanum, an alcoholic tincture of the narcotic. By means of this self-study, he introspectively investigated the effects of the drug on his perceptions, hallucinations, and daydreams and reported his “findings” in “Confessions of an English Opium-Eater,” published in 1821.

De Quincey concluded that opium-induced visions were produced by the dream faculty in the human mind. He believed that the intake of opium stimulated the dream faculty, which in a waking person produced memories and emotions in symbolic patterns that are seen under the influence of the drug. He called those experiences “involutes.”

According to De Quincey, an involute is a complex feeling made up of memories, impressions, and symbols that involuntarily appear to the mind’s eye. The way he presents the “involutes” makes them sound to me like synesthetic perceptions in which sensory elements such as images and sounds mix to form new perceptual unities. Unfortunately, however, De Quincey was not very specific in his descriptions, so they could be taken as either intellectual constructs or synesthetic perceptions. Fortunately, other drug-experimenting writers were more specific in their descriptions of drug-induced perceptions, perceptions that resemble our current notions of synesthesia.

The gothic writer Edgar Allan Poe produced an impressive oeuvre that explored the dark sides of human feelings, all the while assisted by the alcoholism and drug addiction that eventually led to his early death. Drugs played an important role in his explorations of the human soul and likely opened new perceptions and experiences to him, including his becoming aware of his synesthetic perceptions. In his short story “A Tale of the Ragged Mountains,” Poe describes, through his character Augustus Bedloe, the effects of morphine on his sensibility:

‘’I n the meantime the morphine had its customary effect, that of enduing all the external world with an intensity of interest. In the quivering of a leaf, in the hue of a blade of grass, in the shape of a trefoil, in the humming of a bee, in the gleaming of a dewdrop, in the breathing of the wind, in the faint odors that came from the forest, there came a whole universe of suggestion, a gay and motley train of rhapsodical and immethodical thought.”

Poe’s poems are dominated by sensory symbols for the human heart that include his use of darkness, night, cold, and sound (frightening knocks on the door and the squeaking of open windows). The darkness itself evokes synesthetic impressions in him. Poe hears sounds in the shades of black and gray. In his early poem “Al Araaf,” this type of synesthesia steps forward and identifies itself in the second and last lines of the following excerpt:

“Sound loves to revel in a summer night;

Witness the murmur of the grey twilight

That stole upon the ear in Eyraco,

Of many a wild star gazer long ago—

That stealeth ever on the ear of him

Who, musing, gazing on the distant dim,

And sees the darkness coming as a cloud—

Is not its form—its voice—most palpable and loud?”

The murmuring of the gray twilight and the volume of the darkness is almost tangible. The darker the sky, the louder the sound. Poe’s synesthesia shows similarities with the reports of synesthetes who perceive high-pitched sounds as light and low-pitched sounds as dark. Poe was well aware of his perceptual capacities, as evidenced by a footnote to part II of “Al Araaf ”: “I have often thought I could distinctly hear the sound of darkness as it stole over the horizon.” He even seems to have been aware of the bidirectional nature of his synesthesia, for he wrote in the Democratic Review of November 1844: “The orange ray of the spectrum and the buzz of the gnat affect me with nearly similar sensations. In hearing the gnat, I perceive the color. In perceiving the color, I seem to hear the gnat.”

Poe’s “dark” poems and unconventional way of life inspired many poets, including the French poet Charles Baudelaire in Paris some decades later. One of the themes that Baudelaire would elaborate on was that of drugs, sensibility, and synesthesia.

In France, Baudelaire’s poem “Correspondences” in the volume “Les Fleurs du Mal (Flowers of Evil),” published in 1857, started a new romantic interest in synesthesia. The poem would become paradigmatic for poets of the Symbolist movement, who tried to discover a higher, spiritual reality by studying sensory correspondences.

“Correspondences”

Nature is a temple in which living pillars

Sometimes give voice to confused words;

Manpasses there through forests of symbols

Which look at him with understanding eyes.

Like prolonged echoes mingling in the distance

In a deep and tenebrous unity,

Vast as the dark of night and as the light of day,

Perfumes, sounds, and colors correspond.

There are perfumes as cool as the flesh of children,

Sweet as oboes, green as meadows

—And others are corrupt, and rich, triumphant,

With power to expand into infinity,

Like amber and incense, musk, benzoin,

That sing the ecstasy of the soul and senses.”

Baudelaire’s idea of correspondences is slightly different from the current meaning of synesthesia. He related the perception of sensory correspondences to a state of mind where various sensory impressions (perfumes, colors, sounds) corresponded to one another. The perception of a perfume evoked, in other sensory domains, coolness, sweetness, and greenness. And although these qualities were physically distinct, in his perception they were related in the sense of corresponding or talking with each other. He interpreted these correspondences as a voice from a deeper spiritual level of reality.

Baudelaire was inspired by the philosophy of Emanuel Swedenborg, an 18th-century Swedish scientist and philosopher who believed that sensory correspondences in the natural world mirrored correspondences in the spiritual world. Sensory correspondences would reveal not only the unity of the senses but also the unity of the spiritual world.

But what role did Baudelaire reserve for drugs in this vision? In his book of essays, “Les paradis artificiels (Artificial Paradises),” Baudelaire reported extensively on his investigations into the effects of drugs on perception. According to him, the use of hashish brought a person into a state of mind that had an intensifying impact on sensory experiences. He wrote that in a drugged state, he was able to perceive more sensory details with heightened emotional awareness. He believed that when the senses were more open to new stimuli — a state of mind called “hyperesthesia,” or hypersensibility — new correspondences could be revealed. Hypersensibility revealed a deeper layer of consciousness, one in which the sensory qualities had not yet been separated.

The effect of smoking hashish was to uncover them: He wrote that he perceived colors, smells, sounds, and tactile impressions more intensely and as interrelated when he was under the influence of hashish. Perceived correspondences such as colored sounds and musical colors that were placed in the category of temporary hallucinations by his contemporaries were taken as serious perceptions of a deeper layer of consciousness by Baudelaire. Intoxication created by drugs could lead to a mental state of hyperesthesia in which correspondences such as colored sounds and musical colors, appeared:

“It is, in fact, at this period of the intoxication that is manifested a new delicacy, a superior sharpness in each of the senses: smell, sight, hearing, touch join equally in this onward march; the eyes behold the Infinite; the ear perceives almost inaudible sounds in the midst of the most tremendous tumult. It is then that the hallucinations begin; external objects take on wholly and successively most strange appearances; they are deformed and transformed. Then—the ambiguities, the misunderstandings, and the transpositions of ideas! Sounds cloak themselves with color; colors blossom into music.”

Baudelaire participated in a unique experiment of the Club de Hachichins in Paris in 1845. A painter, poet, and musician named Joseph Ferdinand Boissard de Boisdenier organized monthly gatherings that he named “fantasias” held in his luxury apartment in the Hôtel Pimodan on the île Saint-Louis. The French poet and journalist Théophile Gautier, who was a close friend of Baudelaire’s, saved one such invitation. It reads: “Dear Théophile, next Monday the third of the ninth [1845] hashish will be taken at my place under supervision of Moreau and Roche.”

Jacques-Joseph Moreau and Aubert Roche were physicians who were studying the effects of hashish on patients and had published separate papers on the subject. Moreau was interested in using hashish to cure patients by evoking artificial psychoses while Aubert Roche wanted to use hashish to fight outbreaks of pestilence. The work of Aubert Roche has been — rightly — forgotten, but Moreau’s book contains striking insights into modern pharmacology. In 1845, Moreau argues in his book “Du hachisch et de l’alienation mentale (Hashish and Mental Illness)” that mental diseases could be studied by evoking abnormal states of mind in healthy persons by means of hallucination-inducing drugs such as hashish.

He assumed that hallucinations are a result of stimulation of parts of the brain where imagination and memories are located. Moreau carried out the drug experiments on himself and some of his patients. He also tried to convince his colleagues in the hospital to use hashish, but they refused. He found a more positive response from the bohemian artists in Paris, which is how the gatherings of the Hashish Club began.

The meetings, made famous in articles published by Gautier, were attended by many writers and artists of the day including Baudelaire, Honoré de Balzac, Alexander Dumas, Victor Hugo, Gérard de Nerval, and the painters Eugène Delacroix and Honoré Daumier. In one article, Gautier wrote that as he felt himself go under the influence of hashish, he noticed a strong urge to draw, and within five minutes, he had put down over fifteen sketches on paper. One sketch depicted Moreau in Turkish costume, seated at the piano. Gautier represented the synesthetic colors of the piano notes as curly lines above the instrument. After consuming “dawamesque” — a green pasta of hashish, butter, pistachio nuts, almonds, and honey — Gautier reported his perceptions in time units as in a scientific report.

At the beginning of the experience, Gautier was seized by a general freezing sensation and his body felt as though it had become transparent; he felt his eyelashes grew and curled up as gold threads on little ivory wheels. Around him, color avalanches glittered as in a kaleidoscope. Half an hour later, he got into a second hashish flush with even stranger visions of billions of swarming butterflies whose wings made an intensely loud noise as if they were fans. Gautier finally described how his hyperesthesia produced synesthesia-like perceptions:

“Giant crystal flower calices, enormous rose-mallows, golden and silver lilies mounted and opened around me with a crackling like bouquets of fire works. My hearing was developed extraordinarily; I heard the noise of colors. Green, red, blue, yellow sounds reached me in perfectly distinguishable waves.”

Following the lead of Dr. Moreau, Gautier considered these drug-induced synesthetic experiences to be experiences of artificial psychosis. He described it as the frightening experience of the alienation of his own body (which is, in fact, very different from how synesthetes describe their experiences nowadays). Contrary to Baudelaire, who considered sensory correspondences to be revelations of spiritual correspondences, Gautier plainly considered it a disruption in the brain.

As we have seen, the revelation of sensory correspondences by drug use was a subject of 19th-century literature. Some writers took it seriously, but others treated it as fun or a snobbish bijou. From two of the more serious thinkers, however, two opposing views emerged on drug-induced sensory correspondences. The first view, exemplified by Baudelaire, was that correspondences were perceived in a state of hyperesthesia, a hypersensitive state revealing a spiritual unity of the senses. A second view, voiced by Gautier and Dr. Moreau, was that the drug-induced perception of correspondences was a hallucination resembling the hallucinations caused by a mental disorder. Who is right, according to the ideas of contemporary scientists? Can contemporary scientists perhaps offer a third view on the relationship of drug use and synesthetic perception?

During the 1950s and 1960s, there was much experimentation with LSD (lysergic acid diethylamide). Some people reported side effects that sounded like synesthesia when they described their color perceptions. For example, some individuals reported that the LSD added color percepts to nonvisual stimuli such as pure tones. These reports were very similar to the descriptions of hyperesthesia and color hearing reported by Baudelaire and Gautier.

In the 1960s, a pharmacologist named Leo Hollister found that after subjects were given LSD, the addition of pure musical tone to the presentation of a visual flicker altered the color and patterns of the perceived flicker. Later in the 1980s, the British neurologist Peter McKellar observed that a subject who had been given mescaline responded to tactile stimulation by a sharp object by saying; “I’ve got concentric circles like around the top of a radio mast. If you touch me, jagged things shoot up; little sort of jagged things, from the center.”

At the same time, the British perception researcher Richard Gregory subjected himself to an injection with ketamine, an anesthetic drug that was often used in plastic surgery, and reported his perceptions to his fellow-researchers. When they caressed the palm of his hand with a hairbrush, Gregory had “a sensation of red wool, woven in squares, like a tapestry,” and when he moved his finger across the bristles he perceived “purple, red images, clear like hypnologic images that were highly saturated like Turkish tiles, orange and green and red.” When a comb was swapped for the brush on his hand, he got “vivid green and red sensations as the comb moves.”

These studies showed that hallucinogenic drugs led to a higher sensibility for physical stimuli, resulting in co-perceptions such as moving colors and forms. They confirm Gautier’s view that drugs can evoke synesthetic perceptions that are hallucinatory. The participants in these studies were not synesthetes. What happens when a synesthete takes hallucinogenic drugs?

After decades of incidental reports of synesthesia as a side effect of drug-induced hallucinations, drug-induced synesthesia started to become studied more systematically in the 1980s. One of the pioneers in this field is a Washington, D.C.-based neurologist, Richard Cytowic. In his popular book, “The Man Who Tasted Shapes,” he describes the case of his patient Michael Watson, for whom a minty taste in his mouth evokes a tactile sensation that is as cool and fresh as the curve of a glass column in his hand. For Watson, flavors have shape. While he tastes the flavors in his mouth, he also feels the shapes all over his body, but mainly as sensations of objects rubbing against his face or in his hands.

Watson tells Cytowic that his synesthetic perceptions vary in intensity during the day. On mornings after some serious drinking, he hardly feels the flavors in his hands or elsewhere on his body. The neurologist learns that Michael drinks many cups of coffee in the morning to sober up and get over the hangover. Could the use of depressants such as alcohol and stimulants such as coffee affect synesthetic perceptions? Watson participates in an experiment by Cytowic with “socially accepted” drugs — alcohol and coffee. After the intake of alcohol, a taste of spearmint increases the sensation of glass columns in his hands, while after coffee, all that is left is the tactile sensation of some small columns further away.

According to Cytowic, stimulants, like coffee, stimulate the higher cognitive functions in the neocortex (the relatively thin multifold outside layer of the brain), whereas depressants, like alcohol, suppress the responses of the neocortex. Suppression of the rational cortical area lets activity of the emotional limbic system (more centrally located in the brain) emerge and pushes it into the foreground of experience. Cytowic locates the source of synesthetic processes in this limbic system, and thus his predictions that coffee will block and alcohol will enhance synesthetic perceptions were confirmed.

In Cytowic’s studies, unlike in the experiments discussed earlier, synesthesia is not a temporary hallucination. Watson’s synesthesia is permanent and can be slightly modified by taking drugs. Later studies into drug-induced hallucinations of nonsynesthetes confirm Gautier’s reports, but the only study into the modification of synesthetic perception in a synesthete matches Baudelaire’s view. In fact, drug-induced hallucinations and drug-modified synesthesia are two different phenomena.

So the question remains: Is there a direct relationship between synesthesia and drug-induced hallucinations? Though some overlap can be observed in both types of perception, I don’t believe there is.

First, drug-induced hallucinations are temporary, lasting only as long as the drug lasts, whereas synesthetic perceptions are always there throughout one’s life. Second, the perceptions of sensory correspondences change in drug-induced hallucinations, whereas in synesthetic perceptions they are consistent. Third, drug users can distinguish hallucinations they have while under the influence of drugs from their normal states of mind, whereas synesthetes perceive their sensory correspondences while in a normal state of mind. In fact, no observations by others indicate that synesthetes show hallucinatory behavior. Fourth, whereas drug-induced hallucinations are often disruptive to a person’s normal functioning, the “visions” seen by synesthetes don’t interfere with normal life, and in some cases, they help the synesthete perform better, for example, in cases where synesthetes use colors to do mental arithmetic. And lastly, many synesthetes report that they first discover their synesthesia during childhood and not during their first drug experience.

Once dismissed as imagination or delusion, metaphor or drug-induced hallucination, the experience of synesthesia has now been well documented by scans of synesthetes’ brains that show “crosstalk” between areas of the brain that do not normally communicate. What makes it such a fascinating phenomenon is that it raises questions that still perplex scientists. Synesthesia is not an isolated phenomenon in human perception. It is not a fantasy, nor can it be marginalized as an unimportant by-product of a human brain process gone awry. The numerous synesthetes I spoke with when writing my book “The Hidden Sense” regard it as essential in their lives. While reproducing the true experience of synesthesia may be impossible, reorganizing our concept of the sensory channels of the mind is a worthy objective. It can change our view of the human mind, after all, and possibly of the physical world.

Exploring Drug-Induced Synesthesia. By Crétien van Campen. The MIT Press Reader, September 9, 2019.

Crétien van Campen is a Dutch author, editor and scientific researcher in social science and fine arts. He is the author of several books, including “The Hidden Sense: Synesthesia in Art and Science,” from which this article is adapted.

The MIT Press

Oh, to be a synesthete, those rare people with access to an extra layer of perception. Sounds have colors. Words have taste. Colors play music. The list goes on. The phenomenon isn’t totally understood by scientists, but the general idea is that those with synesthesia experience sensory inputs differently than the rest of us.

It’s no wonder that synesthesia is common among artists. But for those of us that just see letters as letters and can’t taste a song, synesthesia is more apt to inspire jealousy than creativity. We simply don’t have the neural link-ups that lead to the ability.

Not so fast, say two researchers from the University of Michigan. In experiments with normal (i.e. non-synesthete) people, Anupama Nair and David Brang say they induced a specific kind of synesthesia with a simple technique. When participants were played sounds in a dark room, around half of them experienced flashes of light, though no actual light was present. It means that synesthesia may be more common that we thought — most of us might simply not encounter the kind of situations that stimulate it.

The research, published this month in the journal Consciousness and Cognition, was inspired by a puzzling experience Brang had as a graduate student.

“While waiting to fall asleep at night with my eyes closed in a dark room, sudden and unexpected sounds (such as the house creaking or a door slamming) would cause a brief but salient flash of light (white or colored, and either encompassing my entire visual field or taking on a complex pattern),” he says in an email.

“Surveying undergraduates, I quickly found that the sensation was quite common while individuals waited to fall asleep at night.”

This is similar to sound-color synesthesia, where sounds will be associated with different, specific images.

Brang, now an assistant professor of psychology at Michigan, teamed up with Nair, and they set out to recreate the experience in the lab. They recruited 21 undergraduates from the university and had them sit in a dark room for five minutes with their eyes closed. A recorded voice then read letters of the alphabet, preceded by a visual attribute like “curved” or “symmetrical.” The participants had to say if the letter possessed the characteristic stated.

After some of these letters, the researchers would play a short beep, and the participants had to press a button if they had seen anything unexpected. Surprisingly, it was fairly common, they found. About 50 percent of the people reported seeing flashes of light in a few different patterns after hearing the beep, though nothing was actually there. Further experiments found that louder beeps would cause the flashes more often and that they were more common if the beep immediately followed the cue to imagine a letter.

In short, the researchers seemed to have activated some sort of latent synesthetic capability in their participants. It shouldn’t actually be so surprising, they say. The areas of our minds that are responsible for compiling and translating various sensory stimuli, like sounds and colors, are actually interconnected in all of us, Brang says.

This helps us understand when someone is talking, for example: we’ll pick up on the sight of someone’s mouth moving, and that helps cue our auditory system to pick out words. These kinds of connections don’t normally create noticeable stimuli, rather, the sight of a mouth moving simply helps jog auditory neurons into action. In the right conditions, though, these interconnections can produce things we’ll actually experience.

“We used a couple of ‘tricks’ to shift the balance of this auditory-visual connection,” Brang says. The researchers damped down the visual input by putting the subjects in a dark room while simultaneously stimulating their visual cortex by asking them to imagine pictures and they used loud sounds that would evoke a strong signal along the auditory-visual pathway.

We all might be potential synesthetes, in other words. Those of us who experience the cross-sensory stimulation in everyday situations might simply have stronger networks of interconnection, allowing the experience to happen more easily. Other studies have shown that people can be trained to associate different letters with colors, and documented the appearance of synesthesia in those with vision loss. There’s also, of course, the experiences of those taking psychedelic drugs like LSD, long known to induce synesthesia. It’s still unknown whether that form of synesthesia occurs in the same way as the non-tripping kind, though.

As for why some participants in the study were still resistant to synesthesia, Brang thinks they might simply not have been stimulated enough or in the right way.

“My hunch is that this is a trait-like difference, such that those who experienced these sensations are more susceptible to them,” he says. “Two possibilities are that this is due to greater visual-cortical excitability in some individuals (since more excitable neurons would fire more easily to the auditory inputs) or a stronger auditory-visual anatomical connection. It should be possible to evoke these sensations in most individuals but it may just take a more tailored context.”

When you’re falling asleep tonight, maybe take a moment and listen — you might get a flash of inspiration.

We Might All Have Synesthesia, New Study Suggests. By  Nathaniel Scharping. Discover Magazine,  April 18, 2019

For most people, a bad toothache feels like a persistent throb or a sharp pain. But without a dentist visit, there’s no way to tell whether it warrants a root canal. A synesthete, however, might wake up one morning and see the tooth glowing orange. For Manhattan-based artist and co-founder of the American Synesthesia Association Carol Steen, physical discomfort manifests as color (usually, a bright chrome orange). And in Steen’s case, much to her dentist’s surprise, she was able to diagnose a dying nerve before any clinical signs of tooth damage.

The word synesthesia means “union of the senses,” and synesthetes — roughly 4 percent of the population — are adults whose senses mingle in a sort of cross-wiring of the brain. Based on self-reporting and scientific case studies so far, there appear to be 80 varieties of these involuntary sensory perceptions. Shapes and sounds can have particular tastes, while letters or numbers can embody distinct personalities and genders. To take examples based on scientific literature, for one synesthete, the sound of a high C on a trumpet induces a flash of Ferrari red. For another, eating chocolate-covered raisins causes a sensation in the fingertips. For a synesthete with “ordinal-linguistic personification,” the number 9 might be a bearded hipster, while someone else swears 9 is a high-ponytailed blonde. It’s that idiosyncratic. Greta Berman, a Juilliard art historian who studies synesthetic artists, explains synesthetes don’t just think 9 is this or that. They know it is, and they will “fight to the end” that a number has a certain persona or is a specific shade. For Steen, five is cadmium yellow medium. Though her father, also an artist, insisted five was yellow ochre. And like most with synesthesia, Steen can’t recall “5” ever being a different hue or not having joined senses.

These days, so many celebrities seem to be proclaiming their synesthesia, it feels, as best-selling novelist and radio host Kurt Andersen references in one of his Studio 360 podcasts, like a kind of neurological “humblebrag.” Kanye has it. So does Beyoncé. And Lady Gaga’s got it, too.

In fact, a growing body of evidence shows synesthesia is more common among creative types and that some of the most imaginative minds — Hockney, Kandinsky, Nabokov — were indeed synesthetic. According to those who study the condition, cross-sensory experiences may offer a particular artistic advantage: a greater aesthetic sensitivity than the rest of us, and thus a greater likelihood to gravitate toward artistic fields. After all, synesthetes are able to express seemingly unrelated concepts in a variety of mediums: numbers with personalities, colors with pain, moving shapes with sound. And unlike their colleagues, synesthetic artists — those who use their neurological trait as a foundation of their practice — respond intuitively to what Steen calls the “multimedia-like stimuli” going on around them. An “ordinary” painter either captures a landscape before her or something she imagines. A synesthetic one paints what she actually visualizes when hearing a specific concerto — or as Steen explained, what she sees when she feels the jab of a tetanus shot.

“There are times when the vision I have is great and I can’t wait to run home to paint what I’ve seen,” said Steen, who is known for incorporating her synesthesia in her art. Her abstract painting Full View is what she perceived when her acupuncturist removed the needles at the end of a session. Still, not everything she experiences is “synesthetically wonderful.” “I assure you that if I smell something really bad,” she explained, “it’s not anything anyone would want to see.” Steen describes the reaction as an immediate physical response. In fact, she listens to music when she goes to the art-supply store, carefully removing the paint-tube cap to see if the color matches the sound she’s hearing.

But until fairly recently, synesthesia had its share of skeptics. In 1980, according to George Washington University neurologist Dr. Richard Cytowic, synesthetes were still often dismissed as “looking for attention” or just “speaking metaphorically,” such as “bitter cold” or “loud tie.” In his book, Wednesday Is Indigo Blue: Discovering the Brain of Synesthesia, Cytowic recalls how colleagues joked about his research subject, Michael, who “claimed” he felt intense flavors running down his arm. According to them, Michael was either “crazy” or “on drugs.” Synesthesia couldn’t be real, because it contradicted the dominant scientific paradigm that senses travel along five separate channels.

Since then, the science of synesthesia has come a long way, thanks to neuroimaging and the ability to connect somebody’s sense of the reality of the world to her brain’s architecture. A person no longer has to “claim” that Wednesday is indigo blue; researchers can compare activity between her cortical areas when she sees the word to a non-synesthete’s brain scan. To take a handful of studies, there’s now a known genetic link in families, as well as a neurological basis for the most common form of synesthesia, “grapheme-color,” when numbers and letters have distinct colors. A 2013 paper in Cerebral Cortex also identified a neural link between feeling and hearing, showing that in rare instances, synesthesia can also be acquired after a stroke. Using MRI, neuroscientists found that, indeed, the body can “mix up” sound and touch even without brain damage.

“We all have a little bit of synesthesia,” said Tony Ro, CUNY Graduate Center professor of psychology and the article’s lead author. Nails on a chalkboard make us cringe; a buzzing mosquito makes us itch. But today, Ro explained, scientists understand the anatomical basis for the seemingly random reactions, and how synesthetes have greater neural crosstalk than the rest of us. Still, for most people, it’s nearly impossible to grasp what intertwined senses are like; how it feels to live with chromesthesia — the “sound-to-color” that Steen has — or her experience of “colored pain.” But at least artists like Steen provide some visual equivalence for non-synesthetes. Steen works in three dimensions, too. Her twisted bronze and steel blue sculpture, Cyto, conveys the shapes and color of the first two syllables of Dr. Cytowic’s name. Even today, the synesthesia community feels tight-knit. In 1993, after hearing Dr. Cytowic on the radio, Steen reached out to discuss her synesthesia, which she’d kept hidden for decades. They soon became friend-colleagues, and she gifted him Cyto as thanks for giving her “knowledge” and “freedom.”

Photographer Marcia Smilack is also known for using synesthesia as a cornerstone of her process. As a “reflectionist” — her term of art — Smilack takes trippy pictures of the ocean’s surface the moment she has a synesthetic reaction, some of which have a Screamesque quality to them. And Smilack appreciates the comparison, feeling an uncanny connection to Edvard Munch, and the “sound waves” she sees in his famous, distorted images. (Incidentally, Berman thinks Munch might’ve been a synesthete too.) “I think of my work as painting by camera,” Smilack explained. “The colors I see are more like colored light than paint pigment.” For example, Cello Music illustrates Smilack’s auditory perceptions of reflections one night, off moving water. “I aimed my camera at the source and clicked the shutter the moment I felt satin against my skin,” she said.

At the same time, synesthesia can lead artists awry. Sean Day is a musician who sees shapes, movements, and colors when he hears timbres. For 20 years, he’s operated the Synesthesia List, an online forum, regularly cited by synesthesia experts and scientists. Day started scoring music in his early teens, composing by the colors he wanted to view and finding inspiration in fellow-synesthete Duke Ellington. In college, however, Day realized his synesthesia was actually hurting his creativity. “I focused way too much on my synesthetic colors,” he wrote in an essay for Oxford’s Handbook of Synesthesia. “I was ignoring what I was learning about balancing orchestration,” Day explained, “and my music sometimes was ludicrous, like mandolins and bagpipes.”

So, by his mid-30s, when writing music, Day started either ignoring his synesthesia completely or, if the piece called for a solo, focusing only on that one color or texture, without trying to combine instruments. Synesthesia does not make you a better artist, he said (emphatically and multiple times). Synesthetes are just as likely to be “crappy untalented musicians” as anybody else. Excellence in any art form comes from talent, practice, and mastery — not from having different sensations as most people. But, he clarified, if music makes you see colors and shapes, you might be more likely to pick up a guitar or sit at a piano in the first place — since music feels so multilayered.

A survey of 358 fine-arts students at three large universities, published by the Creativity Research Journal in 1989, suggests synesthetes are more common on artistic turf. Twenty-three percent of respondents experienced synesthesia in a “spontaneous and consistent mater”— over five times expected in the general population. The study also found that synesthetes scored significantly higher on four standardized creativity measures. For example, they had a mean score of 38.4 (40 being the creative gold standard, 20 the norm) on the Barron Welsh Art Scale, which asks respondents to “like” or “dislike” 86 designs, specially selected to distinguish between the typical judgments of artists and nonartists. As Dr. Cytowic describes, synesthetes see the similar in the dissimilar (music and color; pain and color; syllables and shapes), and people who excel at making metaphors are generally more creative. “But far greater in number than famous artists who happen to be synesthetic, “ he said, “are ordinary synesthetes who happen to be skilled in literary arts, paintings, or playing a musical instrument.”

And creativity has many guises. Marcos Lutyens is a cutting-edge artist who stages “perceptual interventions” at museums like Paris’s Centre Pompidou and the Los Angeles County Museum of Art. He uses hypnosis and performance to challenge the way viewers respond to stimuli, and has worked with synesthetes, especially, to examine how they perceive reality. In San Francisco, Lutyens sent a group of individuals with synesthesia to McDonald’s — the most ubiquitous American place he could imagine. One participant, who experiences words as color, said the Golden Arches symbol is “wrong” because it should be “red.” For another, the kitchen equipment sounds “shuddered [her] neck and back in a softer, indescribable kind of shock.” “What we classify as artistic,” Lutyens said, “is just normal to them.” And artists with synesthesia work outside of traditional venues, too. For instance, Lutyens describes how an award-winning mixologoist, a synesthete based in Manchester, England, Jody Monteith, mixes the color of drink flavors to “tap into the perfect taste.”

“Do synesthetic artists have a common way of seeing even when they aren’t consciously using synesthesia in their process?” asked Greta Berman, who co-curated (with Steen) the 2008 exhibit, Synesthesia: Art and the Mind, at the McMaster Museum of Art in Hamilton, Ontario. According to the show’s catalogue, she (and Steen) brought four recognized, “genuine” synesthetes together for the first time: David Hockney, Joan Mitchell, Marcia Smilack, and Carol Steen. Based on personal writing and his oeuvre, Berman suspects van Gogh was a synesthete too.

“Here’s the difference,” Berman said. “I don’t think Monet had synesthesia. He’s trying to reflect a physical scene, looking directly at a landscape, and not a sensory vision he had.” As an indication of synesthesia, Berman often searches artwork for “Kluver’s form constants”— geometric patterns (often lattice or spider-web-like), discovered by psychologist Heinrich Kluver in the 1920s, which regularly appeared during peyote hallucinations and synesthetic perception. “Anyone looking at paintings by van Gogh, Charles Burchfield, Wassily Kandinsky, and David Hockney, for example, will surely observe these form constants repeatedly,” according to Berman and Steen’s essay in Oxford’s Handbook on Synesthesia.

Yet the true power of synesthetic art may lie in what the 96 percent of us who are non-synesthetes can gain from it. “Synesthesia shows you how different sensory perception can be for everyone,” said Day. He calls it a lesson in “neural diversity” and that synesthetic art “strives towards a new understanding” of what’s “normal” for the human brain. Normal, he explains, is diverse. On the humanist side, Dr. Cytowic said in an email, synesthetic studies affirm subjective points of view: how two people can see the same “objective” thing quite differently — each equally valid — in a time “when citizens are becoming increasingly polarized.“

Most of us will never hear colors or taste shapes. But it is pretty common for a non-synesthete to get chills during an operatic crescendo or the high notes of the “Star-Spangled Banner,” or standing in the Sistine Chapel. These are dual-sensory experiences — auditory, visual, and physical stimulation — but more importantly, a way of deeply inhabiting a moment in time and the world more richly, which is, in the end, what it means to have a genuine connection to art.

Why Do So Many Artists Have Synesthesia? By Jacoba Urist. The Cut, July 7, 2016.