Biosphere
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The fundamental nature of living things challenges assumptions that physicists have held for centuries
By Adam Frank
Give me a young star, and I can use the reductionist laws of physics to predict that starâs future: It will live a million years rather than a billion years; it will die as a black hole rather than as a white dwarf. But the components of a living organism yield something new and unexpected, a phenomenon called âemergence.â
Give me a simple cell from the early days of Earthâs history, and I could never predict that some 4 billion years later it would evolve into a giant rabbit that can punch you in the face. Kangaroos â like humans â are an unpredictable, emergent consequence of lifeâs evolution.
Adam Frank writes:
On October 8, 2024, the field of physics was plunged into controversy. That day, the Nobel Prize in Physics was awarded for discoveries not involving black holes, cosmology, or strange new subatomic particles, but about AI. How could the disciplineâs highest award go to research about machines designed to mimic human brains? Where was the physics in that?
For most of the 20th century, physicists largely ignored living systems. They understood living things as machines, albeit ones made of gooey parts. A subfield called biophysics uncovered specific physical mechanisms behind those molecular machines. Organisms as a whole, however, were not a major concern.
But today, many of my colleagues in physics no longer agree with such dismissals. Instead, we have come to believe that a mystery is unfolding in every microbe, animal, and humanâone that challenges basic assumptions physicists have held for centuries, and could answer essential questions about AI. It may even help redefine the field for the next generation.
The central hubris of physics has long been the idea that it is the most âfundamentalâ of all sciences. Physics students learn about the basic stuff of realityâspace and time, energy and matterâand are told that all other scientific disciplines must reduce back down to the fundamental particles and laws that physics has generated. This philosophy, called âreductionism,â worked pretty well from Newtonâs laws through much of the 20th century as physicists discovered electrons, quarks, the theory of relativity, and so on. But over the past few decades, progress in the most reductionist branches of physics has slowed. For example, long-promised âtheories of everything,â such as string theory, have not borne significant fruit.
There are, however, ways other than reductionism to think about whatâs fundamental in the universe. Beginning in the 1980s, physicists (along with researchers in other fields) began developing new mathematical tools to study whatâs called âcomplexityââsystems in which the whole is far more than the sum of its parts. The end goal of reductionism was to explain everything in the universe as the result of particles and their interactions. Complexity, by contrast, recognizes that once lots of particles come together to produce macroscopic thingsâsuch as organismsâknowing everything about particles isnât enough to understand reality. An early pioneer of this approach was the physicist Philip W. Anderson, who succinctly framed the nascent anti-reductionist perspective with the phrase âMore is different.â Complex-systems science has grown rapidly in the 21st century, and researchers in the field won the Nobel Prize for Physics in 2021.
From a physicistâs perspective, no complex system is weirder or more challenging than life. For one thing, the organization of living matter defies physicistsâ usual expectations about the universe. Your body is made of matter, just like everything else. But the atoms youâre built from today wonât be the atoms youâre built from in a year. That means you and every other living thing arenât an inert object, like a rock, but a dynamic pattern playing out over time. The real challenge for physics, however, is that the patterns that make up life are self-organized. Living systems both create and maintain themselves in a strange kind of loop that no existing machine can replicate.
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Synergy-Entropy
What Makes Living Matter Different?
Living things do something profoundly strange from a physicistâs point of view: they use energy to resist equilibrium.
Left alone, matter tends to spread out, cool down, and fall apart. This is the Second Law of Thermodynamics (the rule behind why hot coffee cools and why buildings crumble).
Life, however, swims upstream. Cells repair themselves. Bodies regulate temperature. Brains anticipate the future.
A single cell is not just a sack of chemicals. It is a self-maintaining process â a dynamic loop that senses, decides, corrects, and persists.
In plain English... Living matter responds with intent-like behavior...
DNA is not just matter; it is instruction. Neural connections are not just wiring; they are memory. Learning is not motion; it is information reshaping itself.
Living systems are best described as information engines â structures that use energy to acquire, preserve, and act on knowledge about the world... Modern physics is shifting... The universe is being shaped by patterns, processes, and relationships that only come into focus when life enters the frame.
Dynamics of change...
Photo via NASA/Goddard Space Flight Center
The biosphere is the global sum of all ecosystems. It can also be termed the zone of life on Earth, a closed system (apart from solar and cosmic radiation and heat from the interior of the Earth), and largely self-regulating.
By the most general biophysiological definition, the biosphere is the global ecological system integrating all living beings and their relationships, including their interaction with the elements of the lithosphere, geosphere, hydrosphere, and atmosphere.
Eukaryotic Cell
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