In his slim but tightly packed “Proust Was a Neuroscientist” (Houghton Mifflin, 256 pages, $24), Jonah Lehrer, a nascent neuroscientist who worked in Eric Kandel’s laboratory, argues that, in understanding the brain, artists and writers got there first, anticipating many major scientific discoveries in their work. Mr. Lehrer can be dazzling, as his mind jumps about — he is still, amazingly, only 25 — but one wonders: Is the salient question, really, which field got there first? Genius is genius, and is always ahead of the pack. Leonardo da Vinci, of course, did it all.

This debut book makes for extremely intriguing reading, but Mr. Lehrer frequently gallops too fast — he alights rather than illuminates — and thus shortchanges the cultural climate and creative imperatives of each individual artist. Seurat gets a mere half of a sentence, and his seminal painting “A Sunday Afternoon on the Island of La Grand Jatte” gets nothing. Yet as William R. Everdell put it in “The First Moderns” (1997): “By dividing optical perceptions into their discrete elements the ‘Grande Jatte’ suggested, in a way that painting never had before, that the phenomenal world — and perhaps the noumenal one as well — was itself irreducibly divided into parts, that continuity was an illusion and atoms the only reality.”

The most mind-boggling omission, given Mr. Lehrer’s title “Proust Was a Neuroscientist,” is that he never mentions that science and studies of the brain were the lifeblood of the Proust household. Proust wrote with such great suggestive skill about the science of the mind not merely because he was so perceptive a novelist, but because he had been raised in a scientific household whose head was dedicated to exploring many of these questions. Proust’s father, Dr. Adrien Proust, was one of the great hommes de science of the Third Republic, having studied with Jean-Marie Charcot, the psychiatrist who taught Freud. In the elder Proust’s more than 20 books (his output was as voluminous as his son’s), he wrote on matters of the brain and neurology, and formulated advanced ideas for preventive hygiene. His most famous achievement was the establishment of a cordon sanitaire around Europe, which saved the continent from mass epidemics of cholera, and, to this end, he traveled to Turkey, India, and Russia. The elder Proust’s great anguish was that, despite his formidable knowledge and grand connections (his other son, Robert, was also a distinguished doctor), no cure could be found for his son Marcel’s asthma. That asthma is the key to unlocking another enormous misperception in the popular memory of “Remembrance of Things Past.” At the risk of stripping the madeleine of its pop-star status (there is a photograph of one on the front cover), let’s take a close look at the famous scene in “Swann’s Way,” which Mr. Lehrer uses to illustrate his theory about the role of taste and smell to the power of recall. The narrator comes in from a damp, cold Parisian night, and his mother hands him a cup of steamy tea — a beverage, we are informed, that he never drinks, but does this one time.

Proust may or may not have known that tea contains methylxanthine, a chemical related to theophylline, which is used in the treatment of asthma to relax the throat muscles — modern cures for asthma weren’t known then. (We can assume, though, that given his childhood condition, Proust had encountered this treatment at least once in his life.)

What follows, the narrator describes, is an initial and inexplicable jolt to his system — not, as most remember it, a flood of memory. It’s a pleasant jolt. The narrator doesn’t know its origin; he keeps drinking the “potion,” but complains that the third time around the tea loses some of its kick. He seems, here, to be describing two distinct events: First, probably due to the methylxanthine in the tea, his body suddenly relaxes and his mood lifts. Then, in his newly relaxed state, memories come to him.

Given the crucial, calming medicinal effect of the tea, one wonders: How important a role did smell really play? The tea the narrator recalls his Aunt Leonie giving him as a child was really a tisane of lily pods, which has a distinctly different smell. And madeleines — even Parisian madeleines — when served at night, as they were in this scene, have no more smell than slightly stale sponge cake. Having worked in the kitchens of both Le Cirque and Le Bernardin, Mr. Lehrer likely boasts an unusually sensitive sense of taste and smell, but it is terribly unlikely that either of these scents could have produced an extended swoon of recollection in even the most sophisticated palate, if the narrator had not been first chemically affected by the methylxanthine: It’s not the nostalgia-laden madeleine we should celebrate as the point of origin for Proust’s multivolume meditation, but the medicine-laden tea!

* * *

Like Picasso, Proust did so much that it’s almost impossible to grasp the enormity and shape of his accomplishments. His autobiographical early novel “Jean Santeuil,” though, contains a telling scene that indicates his complicated relationship to his supremely successful homme de science father. In the story, Jean buys himself his own Christmas present — a story by Anatole France and a sprig of mistletoe, which he puts in a glass of water.

Here, Christmas is depicted as the solitary, ordinary day it actually was for Proust himself: When Adrien Proust shed his humble beginnings training for the priesthood to climb up the rarified social ladder of the Third Republic, he became a stylish atheist, nonchalantly leaving his two sons to be raised in the Catholic Church. Meanwhile, Madame Proust remained faithful to her Orthodox Jewish upbringing, which did not include her sons. (Her great uncle was Adolphe Crémieux, the president of the Israelite Alliance.)

And yet, despite his alienation from both faiths, Marcel Proust’s much-talked-about sense of social rejection is overrated. Though as a child he suffered a very real spiritual abandonment from both parents, many of his closest friends and lovers were Jewish or part-Jewish — the Schiffs, Reynaldo Hahn, the “Revue Blanche” crowd, Leon and René Blum, and Genevieve Halévy Bizet Straus. In a very moving long letter to his friend the progressive Marquis de Lauris (really a cri de coeur to his own scientist/atheist father), he attacks the progressives for going too far in creating a homogenous laic France and abandoning the Catholic Church, leaving France, Proust suggests, spiritually unprotected. Yet it is really Proust, not France, who is the dangling man here. He goes back and forth, at times chastising the church for its anti-Semitism, at times using “we” when referring to the Jews, at times defining himself as a Catholic. He alludes to God, then adds: “which God?”

Proust’s most urgent drive was to unify his intractable universe in one gigantic work, and to this end Ruskin gave him one arm — the unification of religion through transcendental beauty — while the Dreyfus affair gave him the other. In his letters to his mother about the “Affair,” they unite as “we.” He had finally found a non-religious way of becoming the good Jewish son to his mother. With “Remembrance of Things Past,” he would find a nonscientific way of being a good seeking son to his father.

Ms. Solomon is an essayist and novelist and a cultural correspondent of El Pais.