What Is Life?

Overview

About a hundred pages, lectures given in Dublin in 1943 by the Austrian physicist Erwin Schrödinger, published in 1944, asking how the events inside a living organism can be accounted for by physics and chemistry. Schrödinger argues that the gene must be a stable molecule, an aperiodic crystal carrying a code-script in the arrangement of its atoms, and that mutations are quantum jumps.

He explains how life maintains order by feeding on negative entropy from its surroundings, and closes with an epilogue on determinism and free will. Watson and Crick both said the book turned them toward the problem of the gene.

What happens

How physics accounts for life. Schrödinger opens by asking how the events inside a living organism can be accounted for by physics and chemistry, framing biology’s central puzzle in explicitly physical rather than purely biological terms.

The gene as an aperiodic crystal. Schrödinger argues that the gene must be a stable molecule, an aperiodic crystal carrying a code-script in the arrangement of its atoms, a theoretical proposal remarkably anticipating DNA’s actual structure.

Mutations as quantum jumps. Schrödinger proposes that mutations are quantum jumps, extending his physical framework to explain genetic change itself through the same quantum mechanical principles governing atomic behavior.

Negative entropy and life’s order. Schrödinger explains how life maintains order by feeding on negative entropy from its surroundings, reconciling living organisms’ apparent local decrease in disorder with physics’s own second law of thermodynamics.

Applying physics to the organism. Schrödinger extends his framework across the living organism generally, showing how physical and chemical principles might account for biological order and function without requiring separate vitalist explanation.

The epilogue on determinism and free will. Schrödinger closes with an epilogue on determinism and free will, extending his physical analysis into genuinely difficult philosophical territory beyond his own primary scientific expertise.

How to read it

Read Schrödinger’s proposal that the gene must be a stable molecule, an aperiodic crystal carrying a code-script, as anticipating DNA’s actual structure with remarkable prescience nearly a decade before Watson and Crick’s own discovery.

Pay close attention to how the explanation of life maintaining order by feeding on negative entropy gave biology a genuinely novel thermodynamic framework, reconciling living organisms’ local order with physics’s own second law rather than treating life as exempt.

Notice how Watson and Crick’s own explicit acknowledgment that this book turned them toward the problem of the gene documents direct, traceable intellectual influence from a physicist’s speculative lectures to molecular biology’s most consequential subsequent discovery.

Consider the closing epilogue on determinism and free will as extending Schrödinger’s physical analysis into genuinely difficult philosophical territory, a working scientist willing to follow his own reasoning into questions usually left to philosophers alone.

Read this book alongside Darwin’s own Origin of Species to see how Schrödinger’s physical, molecular account of heredity connects to and extends the earlier evolutionary framework Darwin had established without access to any comparable understanding of genetics.

Questions it raises

• Does Schrödinger’s proposal that the gene must be an aperiodic crystal successfully anticipate DNA’s actual discovered structure, or does crediting this theoretical speculation with such prescience overstate its actual specificity compared to what Watson and Crick eventually found?
• How persuasive is the negative entropy framework for explaining how life maintains order? Does this thermodynamic account adequately capture biological organization’s actual complexity, or does it remain too abstract to explain specific living processes in detail?
• What does Watson and Crick’s documented acknowledgment of this book’s influence suggest about how physicists’ theoretical speculation can shape subsequent biological discovery? Does this case illustrate productive cross-disciplinary influence, or an unusual exception to typical scientific development?
• How does the closing epilogue on determinism and free will relate to Schrödinger’s preceding physical analysis of life? Does extending physical reasoning into this philosophical territory strengthen or overreach beyond what his scientific argument actually establishes?
• Given that this book was written before DNA’s actual structure was known, how should contemporary readers weigh its historical significance against its specific scientific claims, some of which subsequent discovery has revised or superseded?
• What does this book’s continued relevance to discussions of physics and biology’s relationship suggest about the durability of Schrödinger’s basic project, explaining life through physical principles, even as specific details have been considerably refined by later genetics?