Matthew Cobb, a professor in the School of Biological Sciences at the University of Manchester, a man whose erudition spans biology, neuroscience, psychology, genetics and other discipline-blurring specialties, wastes no time in telling us what we aren’t going to learn from his book. In 1665, he begins, the Danish anatomist Nicolaus Steno put forth a revolutionary idea about the brain that has been guiding researchers ever since: “To understand what the brain does and how it does it . . . we should view it as a machine and take it apart to see how it works.” And take it apart they have: “We can now make a mouse remember something about a smell it has never encountered,” writes Mr. Cobb, “turn a bad mouse memory into a good one and even use a surge of electricity to change how people perceive faces. . . . We stand on the brink of understanding how patterns of activity in networks of neurons create perception.” Certainly, discoveries about the brain fill bookshelves and breathless news stories, creating the illusion that at any moment we will step over that brink and slide into the blinding sunlight of understanding.
Fuhgeddaboudit, Mr. Cobb says, albeit in his own elegant British prose. Despite unarguable progress in methods of studying the brain, we still haven’t the foggiest idea of how the billions of neurons interact and connect to produce the brain’s activity—to produce, in a word, us, creatures who are merely the product of our neurons, their complicated interconnections and the chemicals that wash through those networks. But what a massive weight that “merely” holds! The brain—any creature’s brain, from maggot to mouse to human—is “mind-bogglingly complicated.”
For years, neuroscientists and science writers have delighted in showing how our theories of the brain’s structure and function have emerged from the dominant technologies of the time: the brain as a machine based on clockwork or hydraulic power; as a result of electrical stimulation (think “Frankenstein”); as a telegraph network; as a telephone exchange; and, today, as a computer with codes and feedback loops, a machine that one day might provide our memories with more random-access memory. “Each layer of technological metaphor has added something to our understanding, enabling us to carry out new experiments and reinterpret old findings,” writes Mr. Cobb. “But by holding tightly to metaphors, we end up limiting what and how we can think.”
“The Idea of the Brain” is an engrossing journey through the centuries, into the profound ways those metaphors shaped (and limited) scientists’ thinking about the mysterious organ in our skulls. The book is divided into three sections: past (prehistory to 1950), present (1950 to today) and future. Originally, the heart, not the brain, was the origin of thinking and feeling; the Bible and the Quran do not mention the brain. That prehistory lives on in our language: we “learn by heart,” we are “heartbroken,” it’s “heartfelt”—try replacing “heart” with “brain” in those terms, says Mr. Cobb, and see how it feels.
From there he is off and running through past theories—electricity throughout the 18th century; brain function, evolution and patterns of inhibition and activation of impulses in the 19th; the discovery of neurons and their intersection at synapses, machine models, and finally the idea of the brain as the locus of control of behavior, throughout the 19th and 20th. Freud has a cameo but is dismissed, correctly, with the following comment: “In reality, Freud had nothing novel or insightful to say about how the brain worked.”
In the book’s second part, on present theories, Mr. Cobb explores memory, circuits, computers, chemistry, localization of function and consciousness. In clear and lively prose, he introduces us to the characters, personalities, and debates of each era, showing that the history of science is full of “chance events, mistakes and confusion,” as he puts it early in the book. “Although no one claimed to be able to properly explain how the brain did what it did,” he writes later, “everyone who wrote about the subject inevitably revealed something about what they thought, through the words they used, the metaphors they employed and the diagrams they produced.”
Thus in 1896 Henri Bergson could write that “the brain is no more than a kind of central telephonic exchange,” because telephone exchanges had been around for about 20 years. Theories that paralleled the inventions of the telegraph and telephone were appealing but imprecise. “The nervous system might be composed of an infinite series of switches, but those switches did not work in the same way as those in a piece of electrical equipment,” Mr. Cobb explains. Likewise, the discovery of synapses and the ensuing revelations about how nerves function blew away the pre-existing metaphors and generated new ones.
The reader will come away from this illuminating history of thinking about the brain with a renewed appreciation of the task that remains. Today it seems logical and obvious that the brain is “like” a computer, but just as Steno could never have imagined the telephone—or Bergson the computer—we cannot imagine what awaits: “Our ideas will be altered yet again by the appearance of new and as yet unforeseen technological developments,” Mr. Cobb writes—and cultural changes as well, because “science is embedded in culture.” The computer metaphor has reached its limits. Who knows what awaits, but in the final section Mr. Cobb offers glimmers of the dazzling possibilities. Perhaps a theory “will somehow pop out of the vast amounts of imaging data we are generating,” or simple neural networks will reveal higher-level organization, or comparative evolutionary studies will illuminate more about the consciousness of other animals and thereby our own, or “unimagined new technology” . . . Our ignorance, as all who labor in science know, is not a defeat but a challenge.
