Horgan’s last book whipped up a small storm. The End of Science (1996) argued that various sciences, their big problems either solved or insoluble, have hit the wall. Scientists protested, conferences convened, pundits pondered, and the storm passed. Nevertheless, one protest registered on the author, who was then a writer at Scientific American. Neuroscientists denied that their science was stymied by the brain’s "sheer complexity." The mind sciences were not ending, they insisted, but just beginning. Chastened, Horgan set out to write The Undiscovered Mind.

Along with neuroscience, the book focuses on the fuzzier sciences that study the mind by trying to control its problems, recount its evolution, or reproduce it in a machine. The mind sciences, Horgan says, haven’t ended. They just don’t get anywhere, and in one chapter after another, he knocks them down. The genetics of behavior can’t explain the mind’s motivations. Psychoanalytic, psychological, and pharmacological therapies can’t cure the mind’s malfunctions. Neuroscience can’t put systems of neurons together and explain the mind’s capabilities. Evolutionary psychology can’t account for the mind’s predilections.

Artificial intelligence can’t reproduce the mind’s complexity. And the loose confederation of mystics who study consciousness barely make sense.

Horgan’s writing is vivid, intelligent without being jargony, and personal without being condescending. The amount of research he has done on the mind sciences—which barely communicate with one another—is impressive. And the reader can’t help but share his impatience with studies on ill-defined subjects, theories that are not only unverified but unverifiable, endless debates over the relative importance of heredity and environment, and highly educated people who want to test psychoanalytic theory with artificial intelligence or explain consciousness using quantum theory. "When it comes to the human brain," he writes, "there may be no unifying insight that transforms chaos into order." The reader can’t help but share that suspicion.

Another thing the reader can’t do—at least this one can’t—is fully trust Horgan’s assessment. He says his goal is to redress his earlier message that the mind’s complexity overwhelms neuroscience. Yet this book’s message, extended to the rest of the mind sciences, is exactly that. Another goal, he says, is to look at the mind sciences with the proper mix of hope and skepticism, and thereby "protect us from [our] own lust for answers while keeping us open-minded enough to recognize genuine truth." But the book details plenty of grounds for skepticism and none for hope.

Let’s assume that the stated goals are window-dressing, that Horgan set out to look for the limitations of the mind sciences, and that he found what he looked for. We distrust scientists who reach conclusions this way. We should distrust science writers who do too.

—Ann Finkbeiner