Schrödinger’s What is Life? and modern science

How accurate wrt our present knowledge is Schrödinger’s presentation of biological evolution in ‘What is Life?/Mind and Matter’? Did e.g. the discovery of the double helix of dna merely deepen his presentation or correct it in some important way? Read the text below and answer.

The prompt contained the full text.

Erwin Schrödinger’s What is Life? is widely regarded as one of the most prophetic and influential scientific texts of the 20th century. When evaluated against our present knowledge, his presentation of biological evolution and genetics is astoundingly accurate in its broad conceptual and physical framework, but factually incorrect in its specific biochemical assumptions.

The discovery of the DNA double helix (and subsequent molecular biology breakthroughs) did not merely deepen his presentation; it fundamentally corrected his hypotheses regarding the material and mechanical nature of heredity, while simultaneously proving his most brilliant theoretical predictions right.

Here is a breakdown of how modern biology both deepened and corrected Schrödinger's presentation.

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1. Where Modern Science Deepened His Presentation

Schrödinger approached biology not as a chemist looking at molecules, but as a physicist looking at information and thermodynamics. In this regard, his predictions were visionary.

• The "Aperiodic Crystal" Schrödinger deduced that the genetic material had to be highly stable (like a crystal) but capable of holding vast amounts of information (which a regular, repeating periodic crystal cannot do). He proposed the concept of an "aperiodic crystal." The discovery of the DNA double helix perfectly realized this concept. The repeating sugar-phosphate backbone provides the stable, crystalline periodicity, while the irregular sequence of the four nitrogenous bases (Adenine, Thymine, Cytosine, Guanine) provides the aperiodic information.
• The "Code-Script" Schrödinger introduced the idea that the arrangement of atoms in a chromosome acts as a "code-script" that dictates the organism's development. This directly anticipated the discovery of the genetic code, where sequences of three DNA bases (codons) correspond to specific amino acids in protein synthesis.
• Order from Order (Negative Entropy) His assertion that living things evade the decay into thermodynamic equilibrium by feeding on "negative entropy" remains a profound and accurate description of bio-thermodynamics. Organisms maintain their internal "order" by exporting entropy (disorder, usually as heat) into their environment.

2. Where Modern Science Corrected His Presentation

Because molecular biology was in its infancy in 1943, Schrödinger had to make several educated guesses based on the physics of his era. Many of these biological and chemical guesses required major corrections.

• The Material of the Gene (Protein vs. DNA)
  • Schrödinger's View: In Chapter 2, he explicitly states: "It is probably a large protein molecule, in which every atom, every radical, every heterocyclic ring plays an individual role..." At the time, proteins were thought to be the only molecules complex enough to carry genetic information.
  • The Correction: The genetic material is Deoxyribonucleic Acid (DNA), not protein. DNA is structurally much simpler in its alphabet (four bases) than proteins (twenty amino acids), which makes it a far better medium for copying and storing a code.
• The Mechanism of Mutation
  • Schrödinger's View: Leaning on Max Delbrück’s target theory, Schrödinger modeled mutations as rare "quantum jumps" or isomeric transitions within the gene molecule, caused by chance thermal fluctuations or X-ray ionizing hits overcoming a specific energy threshold.
  • The Correction: While thermodynamic fluctuations (like tautomeric shifts in DNA bases) do cause a fraction of mutations, modern genetics shows that mutations are overwhelmingly biological and mechanical errors rather than purely quantum-physical ones. They are largely caused by errors made by the enzyme DNA polymerase during replication (insertions, deletions, and substitutions), or by the cell's imperfect repair of chemical/radiation damage.
• The Copying Mechanism
  • Schrödinger's View: He struggled to explain exactly how his aperiodic crystal could perfectly duplicate itself during mitosis, attributing it generally to the "order from order" principle of quantum mechanics.
  • The Correction: The double helix structure immediately revealed a mechanical copying mechanism. Because Adenine always pairs with Thymine, and Cytosine with Guanine, one strand of the DNA serves as a physical template for the other. The copying is carried out by highly complex protein machinery (enzymes), meaning the gene does not passively duplicate via quantum mechanics; it is actively copied by the cell's biological factories.
• The Size of the Gene
  • Schrödinger's View: He estimated the size of a gene to be no more than about a million, or even just a thousand, atoms (a volume of 10 atomic-distances-cubed).
  • The Correction: We now know genes are vastly larger. A single human gene can span tens of thousands to millions of base pairs, comprising millions to billions of atoms.

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Summary

Schrödinger successfully deduced the physics of information storage required for life. He correctly reasoned that heredity required a molecular code-script housed in an aperiodic structure, and he correctly defined the thermodynamic challenges life faces.

However, the discovery of the double helix and subsequent molecular biology corrected his physical chemistry. He viewed the gene as a static protein that mutates via quantum isomerism. We now know the gene is a dynamic nucleic acid that mutates primarily via enzymatic copying errors, and replicates through structural templating rather than pure physical forces.