Book Review: The Quark and Jaguar — Adventures in the Simple and the Complex

ByGeorges Lteif

1. Who Should Read “The Quark and Jaguar — Adventures in the Simple and the Complex“

“The Quark and the Jaguar” was written by Nobel laureate Dr Murray Gell-Mann and first published in 1994. As Gell-Mann describes in the book, his work and career revolved around two themes: particle physics and complexity science.

“The Quark and the Jaguar” tackles particle physics and complexity theory from a unique angle, trying to explain how a complex universe, as we experience it today, can emerge from the simple rules of quantum mechanics and relativity theory.

The common feature of all these processes is that in each one a complex adaptive system acquires information about its environment and its own interaction with that environment, identifying regularities in that information, condensing those regularities into a kind of “schema” or model, and acting in the real world on the basis of that schema.

— Murray Gell-Mann, The Quark and the Jaguar

The book is divided into four parts as follows:

  • Part 1: The Simple and the Complex
  • The first part revolves around Complex Adaptive Systems, their definition, dynamics, and how they help explain diverse phenomena in physics, chemistry, biology, and social sciences. In this part, Gell-Mann also explains the bases for distinguishing between complex, chaotic, and random systems.
  • Next, Gell-Mann explores complexity measures, such as Information Complexity and Algorithmic Complexity. Then, he examines the fundamental notion of schemata, which is central to understanding such systems’ learning and adaptation capabilities.
  • Gell-Mann supports his ideas with physical, biological and social phenomena that we are all familiar with, such as bacterial resistance to antibiotics, language learning in children, and the impact of culture on society and its evolution.
  • Part 2: The Quantum Universe
  • In Part 2 of “The Quark and the Jaguar“, Gell-Mann shifts to a different, but not unrelated, topic than complexity, and that is particle physics. Unlike most popular science books, “The Quark and the Jaguar” is not a popular exposition of The Standard Model of Particle Physics. However, a significant portion of the chapters in this part are dedicated to elementary particles (especially quarks), nuclear forces (especially the strong force), and their interactions (QCD).
  • Instead, Part 2 seeks to explain how quantum mechanical effects shape the universe’s evolution on the tiniest scales but remain undetectable on the larger scales. Central to this explanation is the concept behind the coarse-graining of histories, where a single physical property of interest takes the same value across a class of histories while everything else is allowed to vary.
  • The coarse versus fine-graining method permits the categorizing of events in spacetime and allows us to explain the second law of thermodynamics and the disappearance of quantum mechanical effects from large-scale structures and events.
  • Another genuine tour-de-force in Part 2 discussed probability amplitudes and the interference of histories (of a single particle) in quantum mechanical systems. This profound explanation is almost unparalleled in popular science books. Feynman’s lectures turned books, The Character of Physical Law and QED, come very close as they go into similar depths to make sense of quantum mechanics’ probabilistic nature and to explain well-known effects such as light reflection, diffraction, and interference.
  • Part 3: Selection and Fitness
  • In Part 3 of “The Quark and the Jaguar“, Gell-Mann explores various topics related to selection and fitness in biological and social systems.
  • Gell-Mann’s position is that fitness is not (and perhaps cannot) be well-defined but is, nonetheless, is valuable concept for exploring species’ evolution from one adaption to another.
  • In Part 3, an entire chapter is dedicated to superstition and scepticism. Gell-Mann’s firm stance on religions, cultures, and other belief structures starkly contrasts proponents of different views like Lawrence Krauss and Richard Dawkins. I found this fresh perspective remarkably refreshing as it attempts to scientifically explore the evolutionary advantages of such concepts in social structures.
  • Part 4: Diversity and Sustainability
  • In Part 4, Gell-Mann presents his views on how the human species can live sustainably while preserving the biological and cultural diversities of the biosphere.

2. Themes

  • Complexity Theory
  • Particle Physics and the Standard Model
  • Quantum Mechanics
  • Emergence
  • Biological Diversity
  • Science Disciplines (Physics, Chemistry, Biology, and Social Sciences)
  • Complex Adaptive Systems
  • Learning and Schemata
  • Adaption
  • Evolution
  • Cultures and Belief Systems
  • Quarks, QED, and QCD

3. What Is Great About “The Quark and Jaguar“

Take the famous experiment in which a photon from a tiny source can pass freely through either of two slits on a screen on its way to a given point on a detector — those two histories interfere and cannot be assigned probabilities. It is then meaningless to say what slit the photon came through.

— Murray Gell-Mann, The Quark and the Jaguar

  • Authority:
  • You only need to read a short biography of Murray Gell-Mann to appreciate his direct influence on particle physics.
  • His understanding of quantum mechanics made his exposition on quantum interference, nuclear particle physics, and Quantum Chromo-Dynamics (QCD) unique, original, and insightful.
  • In addition to physics, Gell-Mann’s extensive interests included linguistics, bird-watching, and archeology.
  • Originality:
  • “The Quark and the Jaguar” is the only popular science book I have read that bridges the gap between the tiny and the massive.
  • It explains how simple laws such as quantum mechanics allow the complex (living organism and their ecosystems) to emerge. The text will not leave the reader thirsty for more.
  • Conciseness:
  • The text is generally concise, and Gell-Mann rarely deviates from his topics of interest. Even personal anecdotes are presented to support his general argument.
  • Writing style:
  • Gell-Mann’s writing style is clear, direct, and concise without being dry or dull. The chapters are divided into sections, each of a few paragraphs or pages, focusing on a central idea that Gell-Mann tries to push through.
  • Accessibility:
  • The author assumes the readers know the fundamental principles of physics, chemistry, and biology. Gell-Mann’s exposition on quantum mechanics, for example, focuses on nuclear physics, quarks, the strong force, quantum chromodynamics (QCD), and interference without covering the origins of quantum mechanics or any phenomena not strictly related to these themes.

4. What Was Not Great About “The Quark and Jaguar“

There is not much to dislike about this book. There are, however, a few points to be aware of.

  • Gell-Mann’s explanation of quantum entanglement contradicts mainstream views on how entangled particles decide their final quantum states. Gell-Mann believes the states are decided at the source before the collapse of the wave function during measurement. This view does not adhere to Bell’s theorem and inequality governing the probabilistic outcome of classical vs quantum mechanical randomness.
  • Some concepts, especially those in the last two parts of the book on diversity and sustainability, seemed to me more ideological than scientific. Gell-Mann believes that a simple change in the incentives and reward system will alter people’s behaviour concerning population size and climate change. On the other hand, the book was first published in 1994. We know a lot more today than we used to two decades ago.
  • The author presented some topics (string theory, climate change, neural networks, etc.) that were brief and lacked insights and connections to the main story. These extras added little value to the book, only more pages.

5. Further Reading

We highly recommend the following titles to supplement “The Quark and the Jaguar”:

6. Short Biography of Murray Gell-Mann

Murray Gell-Mann (1929-2019) was an American physicist renowned for his contributions to understanding elementary particles and developing the theory of quarks. His most significant contribution is the formulation of the quark model, which provides a framework for understanding the behaviour of subatomic particles.

Gell-Mann proposed the existence of quarks in 1964 as the fundamental building blocks of protons, neutrons, and other hadrons. He introduced the concept to explain the behaviour of strongly interacting particles observed in high-energy experiments, particularly in the scattering of electrons and other particles off nucleons.

His work on the quark model led to the development of quantum chromodynamics (QCD), a fundamental theory describing the strong force that binds quarks together. Gell-Mann’s insights into the underlying structure of matter have profoundly impacted particle physics and our understanding of the universe at its most fundamental level.

In addition to his contributions to particle physics, Gell-Mann made significant advancements in studying complex adaptive systems and applying complexity theory to various fields, including biology, ecology, and linguistics. He was awarded the Nobel Prize in Physics in 1969 for his contributions to classifying elementary particles and their interactions.

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