Erwin Schrödinger, a pivotal figure in the development of modern quantum mechanics, made a significant foray into the realm of biology with his 1944 book, 'What Is Life? The Physical Aspect of the Living Cell'. Based on a series of lectures delivered in Dublin the previous year, this concise and conversational work challenged scientists and the public alike to consider life's fundamental processes through the lens of physics and chemistry. Schrödinger, known for his work on inanimate atoms, deliberately stepped outside his primary domain to tackle one of science's most profound questions: how the intricate events within living organisms can be explained by established physical and chemical laws.
At the core of Schrödinger's inquiry was the paradox of order in living systems. While the laws of physics dictate that isolated systems tend towards increasing disorder, living organisms exhibit remarkable organisation and the ability to reproduce themselves reliably. He likened the complexity of organisms to finely tuned clocks, pondering how a small amount of 'hereditary substance' could pass on traits so consistently. Written before James Watson and Francis Crick elucidated the structure of DNA, Schrödinger speculated on the nature of this substance, drawing connections to 'quantum jumps' from his own field and suggesting its stability might be explained by quantum theory. He also proposed the necessity of 'negative entropy' – the idea that living things must continuously extract order from their surroundings to counteract the universal tendency towards disorder.
Upon its publication, 'What Is Life?' proved immensely influential, reportedly inspiring numerous physicists to redirect their research towards biology. Its accessible style ensured it reached a wide popular audience, cementing its place as one of the 20th century's most enduring popular science books. However, it was met with a more cautious reception from chemists and biologists. Nobel laureate Max Perutz, for instance, noted that Schrödinger could have consulted existing research on enzymes to address some of his confusions regarding cell division and the stability of hereditary material. The concept of 'negative entropy' also faced scrutiny, with later critics like Philip Ball suggesting Schrödinger might have benefited from engaging with ideas linking entropy and information, such as Leo Szilard's 1929 resolution to Maxwell's demon paradox.
Despite these valid scientific criticisms, the book's enduring appeal lies in its audacious interdisciplinary approach and its ability to frame fundamental biological questions in a way that resonated deeply. Schrödinger's willingness to speculate and to bridge the gap between physics and biology helped to lay conceptual groundwork for future discoveries. His insights, particularly regarding the nature of the hereditary material and the need for living systems to maintain order, proved remarkably prescient, even if his specific mechanisms were later refined by subsequent research.
Today, 'What Is Life?' continues to be read and debated, underscoring its timeless relevance in the ongoing quest to understand the essence of life. Its impact highlights the power of cross-disciplinary thinking and the importance of asking fundamental questions, even when complete answers are not yet available. The book remains a testament to Schrödinger's intellectual courage and his ability to spark curiosity and inspire new avenues of scientific inquiry.