Most of us have experienced, at one time or another, the flat opposite of an epiphany. If an epiphany is the revelation of a truth, an anti-epiphany is the revelation of our inability to grasp a truth. At those moments when we confront a seemingly Unlearnable Thing, we are, to paraphrase Wordsworth, "surprised by dullness" - and we are dismayed that the dullness is our own.

I encountered my most traumatic Unlearnable Thing at Findlay High in the mid-1960s, and its name was chemistry. Even today the thought of test tubes is unsettling, and Bunsen Burners instill mild panic. I teach at a small Maryland college, where faculty meetings are held - to my dismay - in a science lecture hall under the baleful presence of the Periodic Table of the Elements. That old DuPont slogan "BetterLiving through Chemistry" never applied to me: "Lower Self-Esteem through Chemistry" came closer to the mark.

I'm not talking about the advanced study of thermodynamics or covalent bonding. I'm talking about the plain old chemistry class that I was required to take during my senior year, a class in which I gratefully accepted Ds because they weren't Fs. I had no excuses: The textbook was enticing and my teacher was unfailingly patient. Mr. Zimmer, a soft-spoken man with a Marine-style brush cut, told me that he had checked my record and was shocked to see my good grades in other classes. Why wasn't he reaching me?

"It's not you," I assured him truthfully as I promised to study harder and get extra help. As a chemist, however, I was born to fail. If you don't even know what you don't know, you won't know what to study in order to do better. Given my reputation as a "smart" kid, I was ashamed to ask anyone for help, and my grades kept sinking.

I had started chemistry with high hopes. The Periodic Table inside the book's front cover offered a key to the structure of the cosmos. Who wouldn't want to learn about that? The illustrations of various molecules, which resembled my sister's pop-beads, were equally appealing. Plus, my lab partner was a cute girl, the ideal person, I thought, with whom to explore the building blocks of the physical universe.

The book's first chapter traced the history of chemistry, and included a section on the medieval elements: earth, air, fire and water. It appealed to my Buckeye sense of practicality that four things you could see (or with air, feel) mingled to create other things you could see and feel. I tested my comprehension by reducing familiar substances to their probable mixtures. Wrigley's Spearmint, for instance, seemed a fusion of earth and water. Black Jack licorice gum added fire, and if you blew bubbles with it, your breath added air to create a perfect microcosm of the universe right there in your mouth. The thumbnail lives of the great forerunners were also fascinating: the mysterious alchemist-friar Roger Bacon, the oxygen man Joseph Priestley, and the visionary Friedrich August Kekule, whose dream of a snake biting its tale revealed the carbon ring within the molecular structure of benzene. Apparently, chemistry could even enliven your dreams: This was going to be a fun class.

When we turned from the history of chemistry to actually doing chemistry, however, my anti-epiphany began. The Periodic Table did not yield its promised X-ray vision into the secrets of all matter. Why were the elements arranged in this particular way, like students in arbitrarily assigned seats? Why were the "inert" gases also called the "noble" gases? This seemed like praise for laziness. And what made them "inert" anyway? It's not as if I had seen other gases being particularly active.

Goggles gave the lab sessions a scary vibe that was reinforced one day when someone made an ill-advised mixture and noxious fumes drove us out of the room. Unnerved by the proximity of potentially harmful liquids and powders, I shook as I handled droppers and tiny spoons, thereby creating the very dangers that I feared. Ominous substances kept pooling on the tabletop and spreading to my hands, my shirt, my forehead. It didn't help that my partner was far more competent than I was. In an era when science was still considered a "guy thing," ruining an experiment was tantamount to not knowing how to change the oil in your car. A high school boy who looks stupid in front of a cute girl, class after class, might as well have "Loser" burned onto his forehead with hydrochloric acid.

It's hard to pinpoint what made chemistry one of my Unlearnable Things, most of which involved math and science. Maybe it was an inability to link the seen with the unseen: I could watch litmus paper changing color with the best of them, but couldn't fathom how gyrating molecules could make this happen. It seemed impossible that substances could actually change into other substances, that salt could contain two elements that I visualized as baking soda and swimming pool cleanser. Everything seemed maddeningly unreal: Even the elements' names - Argon, Magnesium, Phosphorus – sounded more like ancient gods than bits of matter.

Maybe chemistry promised to make the world too knowable for comfort. Years later I realized that I was the kind of person who prefers ambiguity to clarity, and became an English professor. Literature will make a better fit with someone who likes things open-ended rather than pinned down, provisional rather than definitive.

Or maybe the empirical certitudes of chemistry demanded an optimism that I could not muster. Science is based on the buoyant assumptionthat with good data and reasonable hypotheses, the world can be understood. Even as a kid I may have been pessimistic about the human capacity to understand the world. Maybe there didn't seem to be enough mysteries afoot in Findlay, and I subconsciously wanted what mysteries there were to remain mysterious - not exactly the ideal attitude for success in science. For scientists, the realm of the unknown is both the source and the target of their questions, its boundary the envelope against which their work is always pushing. Something within me resisted that push.

Ironically, my disastrous encounter with chemistry gave me a deep and lasting respect for the scientific method and even a form of "science envy." Although this surely reflects begrudging admiration for a subject that once defeated me, I suspect that most nonscience people secretly share my awe of scientists. There's no fudging in what scientists do, no happy acceptance of the sort of contradictions and paradoxes with which we ordinary folks are content.

Although a scientist might expect crisp results from a story about almost flunking chemistry, a humanist like me can offer only tentative possibilities. One is that any confrontation with an Unlearnable Thing helps in the Socratic quest to "know thyself." I know, for instance, that my relation to chemistry was doomed by, well, bad chemistry - as befits someone whose scientific literacy would be perfectly respectable if I were living in, say, the 12th century.

Another possible lesson is that we all have different gifts. That's something that living in a small town can also teach you. Findlay in the 1960s was the kind of place where everyone knew everyone else's quirks and idiosyncrasies. Our family had one eccentricity that was inescapable: We were militant Democrats in an overwhelmingly Republican town. After every election, my father used to say that the Republicans could run Hitler and Mussolini and still get 85 percent of the vote in Hancock County. Whenever I asked why there were so few Democrats in Findlay, he had the same answer: "It's a mystery to me."

I've spent a lifetime trying to understand people who stand on the opposite side of the political fence, and I can only hope that those folks have done the same with me. Maybe such attempts at mutual respect can be applied to another great divide: the split between those who are good in science and those who are not. Although I hold scientists in awe, I'd like to think that chemists, physicists and mathematicians who marvel at the ambiguities of literature consider what I do to be just as mysterious as I find their work.

A final lesson from my failed attempts at learning chemistry seems far more certain: Whenever I see the scared or sullen face of a student who is struggling in one of my literature classes, I can relate. After all, I know exactly what cluelessness feels like. I learned that long ago at Findlay High, in Mr. Zimmer's chemistry class.

Jeffrey Hammond, who grew up in Findlay, is Reeves Distinguished Professor in the Liberal Arts and Professor of English at St. Mary's College of Maryland. He is the author of a collection of essays, Ohio States: A Twentieth-Century Midwestern (Kent State University Press, 2002), about small-town Ohio life.