Alan Turing and the Invention of the Computer

By David Leavitt

Atlas/Norton. 303 pp. $22.95


Great Breakthroughs in 20th Century Science

By Alan Lightman

Pantheon. 553 pp. $32.50

Science doesn't show much respect for its foundational texts. For one thing, they tend to take the form of technical journal articles that are long on factual equations and short on graceful language. Moreover, science is a forward-looking pursuit; hypotheses are formed, experiments are designed, and papers are written in leapfrog fashion, with each subsequent step surpassing (and often rendering obsolete) the achievements that made it possible.

And yet, as several new books reveal, there is value -- and pleasure -- in returning to earlier breakthroughs, even those that have been made quaint by intervening advances in understanding and technique. Revisiting them lets us, scientist and layperson alike, follow the development of our common stock of knowledge as it was built up brick by brick, rather than trying to comprehend the prevailing theories in their completed forms. And of course, there are the scientists themselves -- often brilliant, always human and sometimes even more fascinating than their work.

One such character is Alan Turing, the subject of David Leavitt's new biography, The Man Who Knew Too Much. Widely credited as a key figure in the development of the computer, Turing was a mathematician with a penchant for logic and philosophy and an openness about his homosexuality that, for his time, bordered on the self-destructive. Born in 1912 in England, he was a mathematical prodigy who became a key member of Britain's military code-breaking team during World War II. He ultimately committed suicide in 1954 -- with a cyanide-dipped slice of apple, no less -- after being sentenced to chemical castration for "gross indecency" with a young man. Though Turing helped usher in the brave new digital age, he was also a tragic victim of age-old bigotry.

But somehow Leavitt, a novelist and creative-writing instructor, never quite connects with his story. He largely skims over the mathematician's fascinating biography and psychological makeup while plodding self-consciously through page after page of not-very-illuminating explanations of Turing's work, like an art student determined to prove that he's just as smart as members of the chess club. The material, admittedly, is challenging, but the reader is left wishing for a guide who found it somewhat less so -- and seemed less insistent on making his own struggles in grasping it so evident.

That distinction is made effortlessly clear in David Bodanis's wonderful 2000 book, E=mc{+2}, reissued this season in honor of the equation's 100th anniversary (Walker, $25). In that "biography" of Einstein's famous theory of relativity, Bodanis takes on even more intellectually challenging material but keeps the hard work of understanding it behind the curtain. And he helps the reader along, building up knowledge step by step as he considers each term of Einstein's equation in turn. Better still, he gives us just enough of the human stories of achievement, hubris, delight and anguish to leaven the heavy intellectual going.

Alan Lightman, the physicist and novelist who wrote Einstein's Dreams (1993), lets the scientists speak for themselves in his deeply satisfying The Discoveries. Lightman selects 25 research papers from the 20th century, starting with Max Planck's 1900 paper on quantum physics and ending with a seminal 1972 paper on the first genetically modified organism. Like aging pop fans arguing over whether the Beatles or the Rolling Stones deserve the No. 1 spot on a list of all-time greatest rock groups, science aficionados will quibble over Lightman's selection of research papers. Why include Einstein's papers on the photoelectric effect and special relativity, but not general relativity? Where are geology and paleontology? (After all, discovering continental drift and ancient mass extinctions changed our view of the world profoundly.) And why stop in 1972? -- surely something of note must have happened in the last quarter of the century.

But such complaints are largely arbitrary in a way that Lightman's list is not. As he notes in his introduction, Lightman chooses to exclude discoveries of primarily practical impact -- Turing's work, for example, or Dolly the cloned sheep in 1996 -- in favor of "those discoveries that most changed thinking and progress in their fields." And he covers his bases nicely; the 25 papers relate to 22 major advances, and each provides a jumping-off point for concise, engaging introductory essays in which he ably provides broader scientific context as well as often illuminating biographical sketches. The end result is a remarkably thorough survey of scientific knowledge and advances throughout the 20th century.

Lightman presents the discoveries of physics, astronomy, chemistry and biology in chronological order, rather than considering each field in turn. The approach creates a perhaps exaggerated sense of the orderly, coordinated advance of scientific knowledge. But it also serves to highlight the dependence of each new step forward on those that came before.

The original articles (in some cases abridged to spare readers some purely technical material) are sometimes easy enough to follow; others Lightman manages to explain; and, despite his best efforts, some (especially for the math-phobic) can only be observed and, ultimately, taken on faith. Lightman's selections include well-known work -- Einstein's theory of special relativity, Heisenberg's uncertainty principle, Watson and Crick's description of DNA structure. But he also highlights more obscure achievements, such as Max F. Perutz's dogged pursuit of the structure and function of hemoglobin in blood. And on three occasions, he highlights crucial experimental work along with the attention-grabbing theoretical papers that came out at the same time. The most famous of these is on the structure of DNA. The brilliance of Watson and Crick's conceptual leap is unquestioned, but Lightman also underscores their reliance on a pilfered look at Rosalind E. Franklin's excellent X-ray images. Similarly, Lightman places richly deserved emphasis on the work of the physicist Lise Meitner and the astronomer Henrietta Leavitt, both brilliant scientists whose contributions were obscured by not-so-scientific prejudice against women and, in Meitner's case, the Nazi persecution of Jews.

Lightman is a physicist by training, and it shows in his selection of papers -- roughly 2 to 1 in favor of physics over biology -- and his handling of some of the biological material. This is particularly troubling in his essay on Alexander Fleming and the discovery of antibiotics, which is marred by the kinds of minor errors and inaccuracies that come from not quite understanding your material. (The agar that microbiologists use in petri dishes is not a nutrient; antiseptics and antibiotics are not the same; protozoa and bacteria are not, typically, the same size.) These are subtleties, to be sure, but it's a shame to let undergraduate-level errors mar the otherwise masterly handling of biological themes.

Still, Lightman does an admirable job of guiding us through it all, even if some tours are more intimate than others. In his penultimate chapter, Lightman quotes the physicist Jerome Friedman, one of the discoverers of the quark, as saying, "Most of science is having a wonderful time." Lightman clearly agrees with that sentiment, and his enjoyment of the material shines through.

In dealing with the development of scientific thought, both Leavitt and Lightman highlight a painful irony -- scientists' tendency to overlook their own literature. From the time he was a student, Turing seems to have squandered a good deal of his time and effort working out solutions to problems that others had already solved. And Lightman points out a half-dozen episodes where the progress of science was slowed because researchers were not aware of each other's work. It's a poignant reminder that even the most brilliant are capable of foolishness and, perhaps, also a gentle jab at his scientific colleagues. There is value after all in looking back even as they push forward. *

Thomas Hayden is a science writer living in Washington, D.C.