In a Flight of Starlings

1. Science Demands Public Trust and Transparency

At this moment in time, perhaps more than any before it, it is essential that the public have a fundamental understanding of the practice of science—that is to say, not only the results at which scientists arrive but how they do so.

Urgent understanding. In an era fraught with global challenges like climate change and pandemics, a fundamental public understanding of science is paramount. It's not enough for citizens and politicians to merely accept scientific findings; they must grasp the scientific process itself to make informed decisions and trust the warnings science provides. The recent COVID-19 pandemic tragically illustrated the consequences of science rejection, with many refusing vaccinations despite overwhelming evidence.

Building trust. Scientists cannot simply demand trust; they must actively "show their work" in an engaging way. This involves demonstrating the toil, doubt, successes, and failures inherent in scientific inquiry, and explaining how consensus is achieved and discoveries are validated. Without this transparency, society risks moving in the wrong direction on critical issues such as global warming, infectious diseases, and resource depletion.

Beyond results. The author's own research into starlings' collective behavior serves as an example of illuminating scientific practice. By starting with a complex, everyday phenomenon, he emphasizes that science isn't confined to laboratories but seeks to understand the world around us, making its truths accessible to everyone. This approach helps demystify science and fosters a deeper appreciation for its methods.

2. Complexity Emerges from Simple Interactions

The flocking of starlings held a particular fascination for me, because it was connected by a common thread not only to my research but to so many other studies in modern physics that attempt to understand the behavior of systems composed of a large number of interacting components or actors.

Collective phenomena. Observing the mesmerizing murmurations of starlings, where thousands of birds move in perfect unison, raises fundamental questions about how complex collective behavior arises from simple individual interactions. This phenomenon, seen in flocks, shoals, and herds, suggests a self-organized system rather than one directed by a single leader. The challenge for scientists is to uncover the underlying rules governing these interactions.

"More Is Different." Nobel laureate Philip Warren Anderson's concept, "More Is Different," posits that increasing the number of components in a system leads to qualitative, not just quantitative, changes. This means that the collective behavior of many interacting entities can be far more complex and surprising than the sum of their individual parts. The author's work extends statistical mechanics, traditionally applied to inanimate entities like atoms, to living systems.

Starlings' secrets. Through meticulous 3D reconstruction of starling flights, the author's team discovered that interaction depends on topological rather than metric distance. Birds react to their closest neighbors, regardless of absolute distance, allowing information about turns to propagate incredibly fast. This research revealed:

• Flocks are disk-like, explaining rapid shape changes.
• Density is higher at the edges, a defense against predators like peregrine falcons.
• Birds maintain greater distance front-to-back than side-to-side.

3. Scientific Progress is a Collaborative, Iterative Journey

The fact that no one else has succeeded is scarcely off-putting. This, after all, is the scientist’s calling: to imagine or to do what no one has done before.

Historical context. The author's early years at Sapienza University in Rome, starting in 1966, illustrate a dynamic scientific environment shaped by student movements and a generational shift. The 1968 occupations broke down barriers between students and faculty, fostering a sense of camaraderie and intense intellectual exchange. This period saw young, brilliant minds like Nicola Cabibbo and Francesco Calogero rise rapidly, reflecting an explosion in Italian universities and strong funding for physics.

Communication challenges. Scientific collaboration in the 1960s and 70s faced immense communication hurdles. International phone calls were prohibitively expensive, faxes were rare, and computers were cumbersome machines relying on punched cards. The anecdote of dictating a crucial scientific paper over the phone, leading to a Nobel laureate's name being omitted, highlights the difficulties of disseminating information rapidly and accurately.

Evolving theories. The journey of understanding elementary particles, from the "bootstrap" theory to the eventual acceptance of quarks and quantum chromodynamics (QCD), exemplifies the iterative nature of science. Ideas like quarks, initially dismissed as mathematical simplifications, gained credibility with new experimental data and theoretical refinements. This process, often involving competing schools of thought and unexpected turns, ultimately led to breakthroughs like the GIM mechanism and string theory.

4. Intuition and Serendipity Drive Breakthroughs (and Missed Opportunities)

I’ve never been able to figure out if having a Nobel Prize slip from under your nose at twenty-five is something to be mentioned with pride or one of those slightly shameful secrets that is best forgotten.

A missed Nobel. The author recounts a personal anecdote of narrowly missing a Nobel Prize opportunity at age 25. While working on phase transitions, he had a conversation with Gerard 't Hooft about asymptotically free theories. Despite knowing Gell-Mann's "color charge" theory, the crucial connection to apply 't Hooft's beta function calculation to quarks was not made. This oversight allowed Politzer, Gross, and Wilczek to later make the connection and win the Nobel Prize for quantum chromodynamics (QCD).

The role of intuition. This story underscores the critical role of intuition and the ability to connect disparate ideas in scientific discovery. The author's initial, hasty calculation of the beta function, and his subsequent failure to link 't Hooft's result with Gell-Mann's quark model, illustrate how even brilliant minds can overlook crucial insights. It highlights that breakthroughs often require not just deep knowledge, but also the serendipitous alignment of information and a prepared mind.

Learning from errors. The author reflects on how researchers often pass by great discoveries without grasping them, sometimes due to preconceived notions or a lack of immediate connection. Like the doctor who observed penicillin but dismissed its medical use, scientists can be convinced of the "uselessness" of an observation. This experience taught the author the importance of giving problems more than "half an hour's thought" and remaining open to unexpected applications of theoretical results.

5. Phase Transitions Reveal Universal Principles of Matter

Water boils, water freezes, and this is very strange indeed. We see a substance suddenly transform before our eyes, just because of a change in temperature.

Everyday mysteries. Phase transitions, such as water boiling or freezing, are common phenomena that pose profound questions for physicists. These abrupt changes in state are collective mutations, not individual molecular events. Understanding why they occur at specific temperatures and how microscopic behavior translates into macroscopic transformations has been a central challenge in physics since the early 20th century.

Two types of transitions. Phase transitions are broadly categorized into two types:

• First-order: Characterized by latent heat (energy absorbed/released without temperature change) and no microscopic warning of impending transformation (e.g., water freezing).
• Second-order: Occur continuously without latent heat, marked by a "spontaneous breaking of symmetry" and the emergence of an "order parameter" (e.g., a magnet losing its magnetization above a critical temperature).

Universality classes. A surprising discovery is that the behavior of diverse magnetic systems near their critical temperature follows the same mathematical trend, regardless of their microscopic details. This led to Leo Kadanoff's concept of "universality classes," where phenomena with similar critical exponent values belong to the same class. This suggests a Platonic view of nature, where a few fundamental "Ideas" govern a wide range of physical systems. Kenneth Wilson's renormalization group (RG) formalism, for which he won the Nobel Prize, provided the tools to calculate these critical exponents.

6. Disorder Unlocks New Physics Paradigms

Often the best work achieved in a life spent in research happens by accident. You start out on one road only to arrive at a quite unexpected destination.

Accidental discovery. The author's most significant contribution, the theory of spin glasses, began unexpectedly while trying to solve an elementary particle problem using the "replica method." This mathematical technique, which involves replicating a system multiple times, yielded inconsistent results when applied to disordered systems like spin glasses, prompting the author to investigate its reliability.

Spin glasses. These metal alloys, like gold with diluted iron, exhibit unique magnetic phase transitions that mimic the slow, non-equilibrium behavior of glass, wax, or bitumen. As temperature drops, their spins become "stuck" in random, frustrated configurations, never reaching a true equilibrium. This "frustration" arises from conflicting interactions, where some spins try to align while others try to oppose each other, creating a complex landscape of many possible equilibrium states.

A new order parameter. The breakthrough came when the author realized that the order parameter for spin glasses was not a simple number, but a function—an infinite set of numbers. This indicated that disordered systems at low temperatures exist in a vast number of different equilibrium states simultaneously, a totally unexpected discovery. This conceptual shift, initially derived through a "pseudo-mathematical formalism" and later physically interpreted with collaborators, provided a powerful tool for understanding a wide range of disordered systems, from packing spheres to the functioning of the brain.

7. Metaphors Bridge Disciplines, But Mathematics Unifies Them

The same mathematical abstraction can be projected onto disparate physical systems, and each of these perspectives enlightens us on different aspects.

Intuition and metaphor. Scientific progress often begins with intuition and the use of metaphors, which act as heuristic tools to transfer images and ideas between disciplines. From Darwinian selection influencing quantum mechanics to organisms viewed as machines, metaphors play a crucial role in the early stages of scientific thought. However, the author cautions against the "pernicious" misuse of metaphor, where concepts are transposed without rigor, leading to arbitrary conclusions or dangerous theories like social Darwinism.

Physicists' approach. Physicists, while using metaphors, tend to "dismantle" them by translating concrete phenomena into mathematical language. When different physical systems, like swaying wheat and ocean waves, can be described by the same or similar equations, they cease to be mere metaphors for each other. Instead, they become "different physical incarnations of the same mathematical representation," revealing a deeper, underlying unity.

Cross-fertilization. This realization that disparate systems can share the same mathematical structure leads to rapid advancements through "cross-fertilization." Techniques developed in one field, like the renormalization group from quantum field theory, can be successfully applied to another, such as the statistical mechanics of phase transitions, and then flow back, enriched with new insights. This shared mathematical framework allows concepts and techniques to be carried between disciplines, justifying predictions in one field based on findings in another, moving beyond mere analogy to a deeper, structural correspondence.

8. Ideas Are Born from Unconscious Incubation and Persistent Inquiry

Very often we take for granted that thought is verbal and that unconscious reasoning is not.

The creative process. The birth of scientific ideas, even "microcreativity" in daily research, often follows distinct phases described by mathematicians Poincaré and Hadamard: preparation, incubation, illumination, and formulation. The incubation period, where the problem is consciously abandoned, highlights the crucial role of unconscious thinking. This is a common experience, from solving programming bugs during a drive to suddenly formulating a complete strategy for a long-standing problem.

Nonverbal thought. While we perceive thought as verbal, the author suggests that nonverbal thought precedes and underpins it. Just as a complete sentence exists in our mind before being articulated, the outline of a mathematical proof or a physical solution might exist nonverbally before being formalized. This unconscious processing is vital for mathematical intuition, where a theorem's "meaning" is grasped before its rigorous proof is constructed, and for physical intuition, which can drive progress even when based on initially flawed arguments.

The power of information. Sometimes, a minimal piece of information can trigger a breakthrough. The anecdote of a friend instantly deriving a complex proof simply by being told it was demonstrable, or Einstein's "happiest thought" about gravity after hearing a housepainter's experience, illustrates this. These moments of insight, often built on years of prior work and unconscious processing, underscore that intuition is not magic but a highly evolved capacity to connect information, even if the explicit reasoning only comes later.

9. The True Value of Science is Cultural, Not Just Practical

“Its value lies in the love of culture: it is like painting, sculpture, poetry, and like all of those activities of which Americans are patriotically proud, it does not serve to defend our country but makes our country worth defending.”

Beyond utility. Richard Feynman's provocative quote, "Science is like sex: sometimes something useful comes out, but that is not the reason we are doing it," encapsulates the intrinsic motivation of many scientists: the sheer joy of solving puzzles and expanding knowledge. While practical applications have always been important for funding and societal prestige—from ancient astronomy aiding navigation to Galileo's efforts to determine longitude—the core drive is often intellectual curiosity.

Funding and purpose. Historically, institutions like the Lincean Academy and the Royal Society were established to coordinate research, often with an explicit purpose of promoting "useful knowledge." However, the author notes that society, which funds science, often cares little for scientists' passions, as highlighted by Nikolai Bukharin's view that science's objective social role is its practical importance. Yet, pure science is indispensable for technological development, providing the foundational knowledge, conceptual frameworks, and even acting as a proving ground for high-tech goods.

Defending science. Despite its utility, science faces growing anti-scientific sentiment and distrust. The author argues that this may stem from perceived scientific arrogance or a presentation of science as inaccessible "magic." To counter this, science must be defended not just for its practical benefits but for its profound cultural value. Robert Wilson's famous testimony, equating the value of a particle accelerator to art and poetry, powerfully articulates that science, as a pursuit of knowledge, makes society "worth defending." Making science accessible and intertwining it with broader culture is crucial for its future.

Last updated: December 30, 2025