The Discrete Charm of the Machine: Why the World Became Digital by Ken Steiglitz (review)

A theater critic is said to have described the performance of an English stage actor this way: "Each word is sent individually gift packed." The human voice is analog (a continuous sound wave), and speech is discrete, as opposed to a grunt. Shakespearean words carry far more information than most, and so it is critical that actors deliver them with great clarity. But like any delivery, the trip can be full of potential noisy disruptions: the theater's acoustics, air conditioning or outside traffic—and if it is a recording, static and other noises that are inherent in the equipment. Such analog recording will eventually be unreadable if transferred or edited repeatedly.

The Discrete Charm of the Machine addresses the history of "discretization" that led to faster and safer delivery of information, resulting in, among other things, the Internet today. Along the way, the ability to package information also allowed that information to be modified or enhanced. And more importantly, such "bits" can be recombined to perform computations. Steiglitz traces the first analog computer to the 70 BCE Antikythera mechanism, pieces of which were discovered by divers in the Aegean Sea in 1900. "The device consists of a clockwork of at least 30 intermeshing gears with different numbers of teeth . . . connected to dials [that] . . . show the movement of the sun, moon, and probably the five then-known planets" as the crank is turned (p. 109). The "program" here is determined by how different size gear teeth mesh with others—it is inherent in the machine and not separable.

The first device to successfully store a program independent of the machine that executed it is the Jacquard loom (1804), which made intricate Jacquard weave fabrics. Joseph Marie Jacquard (France, 1752–1834) used punch cards to control the needles that made the design. But each set of cards could make only a single pattern. It took well over a century before Alan Turing (Britain, 1912–1954), whose Turing machine extended this punched-card idea to a theoretical infinite tape consisting of cells with either "0" or "1" and a control head to read or change those cells. He also used the idea of a computer's "state," which determines the next step. This idea of "conditional execution" originated with Charles Babbage (Britain, 1791–1871), a mathematician and inventor who first conceived the idea of machine calculation.

Here, Stieglitz, a computer scientist, brings up the idea of scale: Humans occupy the middle scale, between the subatomic and the astronomical. He uses terms like Planck's constant and Heisenberg's uncertainty to illustrate his point, leading to speculation on a superfast quantum computer. However, he does not provide a human perspective: The human body-brain can only receive signals in this middle scale. For example, we have no receptors for ultraviolet light and cannot perceive sunburn—the pain the next day is from tissue damage. How far should we search—and make use of—scales and calculations outside of our perceptual and cognitive capabilities? If a computer returns an answer we don't understand, how do we know if it is an insight or a short-circuit (like a seizure in humans)? If information is the removal of uncertainty, as the author asserts, how much can we trust this certainty if it cannot be explained to us? For example, a current intractable problem for Google and the U.S. Army alike is the case of adversarial examples in deep learning: Scientists, by changing a few pixels, can make a machine call a dog a rifle, for example.

For the moment, happily, Steiglitz does not see artificial intelligence overtaking humans soon. But he claims there is no "analog magic" in the brain: Neurons are simply valves—excitatory or inhibitory. The Halle Berry neuron, however, suggests otherwise. In experiments in the brains of patients undergoing open brain surgery (with consent), one monitored...