The book’s immediate impact can be seen from the enthusiastic reviews it received in both the popular press and in scientific journals. There were over 60 reviews in the four years after publication, although few writers noticed what now seem to be far-seeing ideas — the aperiodic crystal and the code-script — and it was translated into German, French, Russian, Spanish and Japanese.
There were two extended reviews in the leading scientific weekly Nature, one by geneticist J.B.S. Haldane, the other by the plant cytologist Irene Manton. Haldane got straight to the heart of the matter, picking up on the aperiodic crystal and the code-script innovations and making a link with the work of Koltsov. Manton also noted Schrödinger’s use of the term code-script, but she took it to mean “the sum of hereditary material” rather than a particular hypothesis about gene structure and function. The New York Times reviewer put his finger on the central point:
“The genes and chromosomes contain what Schrödinger calls a ‘code script,’ that gives orders which are carried out. And because we can’t read the script as yet, we know virtually nothing of growth, nothing of life.”
In contrast, some scientists later recalled they’d been unimpressed by the book. In the 1980s the Nobel Prize-winning chemist Linus Pauling claimed that he was “disappointed” on reading What Is Life? and stated, “It was, and still is, my opinion that Schrödinger made no contribution to our understanding of life.”
Also in the 1980s, another Nobel laureate, biochemist Max Perutz, wrote of Schrödinger: “What was true in his book was not original, and most of what was original was known not to be true even when the book was written.” In 1969, geneticist C.H. Waddington criticized Schrödinger’s aperiodic crystal concept as an “exceedingly paradoxical phrase.”
As well as these retrospective criticisms, some dissenting views were voiced when the book first came out. In a review, Delbrück was critical even though he received a publicity boost from Schrödinger’s espousal of his work in the Three-Man Paper. He claimed Schrödinger’s term aperiodic crystal hid more than it revealed:
“Genes are given this startling name rather than the current name ‘complicated molecule.’ … There is nothing new in this exposition, to which the larger part of the book is devoted, and biological readers will be inclined to skip it.”
This was distinctly ungenerous, as Schrödinger’s hypothesis was, in fact, quite precise and did not simply involve coining a new name. Delbrück concluded by grudgingly accepting that the book “will have an inspiring influence by acting as a focus of attention for both physicists and biologists.”
In another review, Muller said that he, too, expected the book would act as a catalyst for “an increasingly useful rapprochement between physics, chemistry and the genetic basis of biology.” Muller clearly felt aggrieved that Schrödinger had not cited his work, and he pointed out that he had suggested the parallel between gene duplication and crystal growth in 1921 (though Muller decided not to mention that he took this concept from Troland). He also dismissed the idea that there was anything novel in Schrödinger’s discussion of order and negative entropy, as these were both “quite familiar to general biologists.” Neither Delbrück nor Muller made any comment about the code-script idea.
Despite their overall skepticism, Delbrück and Muller were absolutely right: Schrödinger’s book did indeed inspire a generation of young scientists. The three men who won the Nobel Prize for their work on the structure of DNA — James Watson, Francis Crick and Maurice Wilkins — all claimed that What is Life? played an important part in their personal journeys toward the double helix.
In 1945 Wilkins was handed a copy of What is Life? by a friend when he was working on the atomic bomb in California. Shaken by the horror of Hiroshima and Nagasaki, Wilkins was seduced by Schrödinger’s writing and decided to abandon physics and become a biophysicist. Crick recalled that his 1946 reading of Schrödinger “made it seem as if great things were just around the corner.” Watson was an undergraduate when he read What is Life? and as a result, he shifted his attention from bird biology to genetics.
Even though some of the ideas developed in What is Life? were visionary and the book undoubtedly inspired some individuals who played a central role in 20th-century science, there are no direct links between Schrödinger’s lectures and the experiments and theories that were part of the decades-long attempt to crack the genetic code, and historians and participants differ about the significance of Schrödinger’s contribution.
The view of mutation put forward in the Three-Man Paper, which Schrödinger espoused so vigorously, had no effect on subsequent events, and his suggestion that new laws of physics would be discovered through the study of the material basis of heredity was completely mistaken. Even the code-script idea, which looks so prescient today, had no direct effect on how biologists looked at what was in a gene. None of the articles that later formed part of the discovery of the genetic code cited What is Life?, even though the scientists involved had read the book.
In fact, the meaning of Schrödinger’s “code-script” did not have the same richness as our “genetic code.” Schrödinger didn’t think there was a correspondence between each part of the gene and precise biochemical processes, which is what a code implies. Nor did he address the issue of what exactly the code-script contained, beyond the vague suggestion of a plan.
Ask any biologist today what the genetic code contains, and they will give you a one-word answer: information. Schrödinger did not use that powerful metaphor. It was completely absent from his vocabulary and his thinking, for the simple reason that it had not yet acquired the abstract, wide-ranging meaning we now give it.
“Information” was about to enter science, but had not done so when Schrödinger gave his lectures. Without that conception of the content of the code, Schrödinger’s insight was merely part of the zeitgeist, a hint of what was to come rather than a breakthrough that shaped all subsequent thinking.