Evolution is not only the process that explains the adaptability of living organisms, it is also, it seems, the principle that governs the whole of nature. A published work in the prestigious Proceedings of the National Academy of Sciences describes "a missing law of nature", which states that complex natural systems evolve towards more structured, diverse and complex states. In other words, evolution is not limited to life on Earth, but also occurs in other highly complex systems, from planets and stars to atoms, minerals and much more.
The study was carried out by a team of nine people - leading scientists from the Carnegie Institution for Science, the California Institute of Technology (Caltech) and Cornell University, as well as philosophers from the University of Colorado.
The "macroscopic" laws of nature describe and explain the phenomena observed daily in the natural world. The natural laws of force and motion, gravity, electromagnetism and energy, for example, were described over 150 years ago. But one question remained unanswered. The one posed nearly a century ago by physicist Erwin Schrödinger - famous for his cat in a box - who asked how nature seemed to build itself into increasingly complex systems if the second law of thermodynamics - according to which everything cools down - were true. The most brilliant minds of the last 80 years have apparently failed to come up with an answer so far.
" The study, led by Carnegie astrobiologist Professor Michael Wong, is like a breeze of fresh air blowing across the difficult terrain at the junction of astrobiology, systems science and evolutionary theory." exclaims Milan Cirkovic of Oxford University's Institute of the Future of Humanity. In the heap of attempts to solve this enigma over the last 80 years, Wong and his colleagues offer perhaps the best chance yet.
Complexity of the natural world
The new research presents a modern addition: a macroscopic law recognizing evolution as a common feature of complex systems in the natural world, which are characterized as follows:
- they are made up of many different components, such as atoms, molecules or cells, which can be arranged and rearranged repeatedly;
- They are subject to natural processes that lead to the formation of countless different arrangements;
- Only a small fraction of all these configurations survive in a process known as "selection for function";
- Whether the system is alive or not, when a new configuration works well and the function improves, evolution takes place.
The authors' "law of increasing functional information" states that the system will evolve "if many different configurations of the system undergo selection for one or more functions". Michael L. Wong, Carnegie astrobiologist and first author of the study, explains, "An important element of this proposed natural law is the idea of 'selection for function'."
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In the case of biology, Darwin equated function primarily with survival, i.e. the ability to live long enough to produce fertile offspring. The new study broadens this perspective by noting that there are at least three types of function in nature.
The most basic function is stability: stable arrangements of atoms or molecules are selected to endure. Dynamic systems with a continuous supply of energy are also selected to endure. The third and most interesting function is "novelty", i.e. the tendency of evolving systems to explore new configurations, sometimes leading to surprising new behaviors or characteristics.
The evolutionary history of life is rich in novelties: photosynthesis evolved when individual cells learned to harness light energy, multicellular life evolved when cells learned to cooperate, and species evolved through advantageous new behaviors such as swimming, walking, flying and thinking.
The same type of evolution occurs in the mineral kingdom. The first minerals represent particularly stable arrangements of atoms. These primordial minerals served as the basis for subsequent generations of minerals, which contributed to the origins of life. The evolution of life and that of minerals are intimately linked, as life uses minerals to make shells, teeth and bones. Indeed, the Earth's minerals, which numbered around twenty at the dawn of our solar system, now number almost 6,000, thanks to increasingly complex physical, chemical and ultimately biological processes that have taken place over 4.5 billion years.
In the case of stars, the article notes that only two major elements - hydrogen and helium - formed the first stars shortly after the big bang. These first stars used hydrogen and helium to make around twenty heavier chemical elements. The next generation of stars built on this diversity to produce almost 100 other elements.
Evolution is everywhere
"Charles Darwin eloquently described how plants and animals evolve by natural selection, with many variations and characteristics of individuals and many different configurations," explains Robert M. Hazen of Carnegie Science, co-author of the study and leader of the research. "We argue that Darwinian theory is just one very specific and important case within a much larger natural phenomenon. The idea that function selection drives evolution applies equally to stars, atoms, minerals and many other conceptually equivalent situations in which many configurations are subject to selective pressure."
The co-authors themselves represent a unique multidisciplinary configuration: three philosophers of science, two astrobiologists, a data scientist, a mineralogist and a theoretical physicist.
Professor Wong points out: " In this new article, we consider evolution in its broadest sense, i.e. change over time, which encompasses Darwinian evolution based on the peculiarities of "descent with modification". "The universe generates new combinations of atoms, molecules, cells and so on. Combinations that are stable and can generate even more novelty will continue to evolve. This is what makes life the most striking example of evolution, but evolution is everywhere."
Among the many implications, the article proposes:
- an understanding of how different systems possess varying degrees of evolutionary capacity. Potential complexity" or "future complexity" have been proposed to measure the degree of complexity that an evolving system could reach.
- indications of how the rate of evolution of certain systems can be artificially influenced. The notion of functional information suggests that the rate of evolution of a system can be increased in at least three ways: (1) by increasing the number and/or diversity of interacting agents; (2) by increasing the number of different configurations of the system; and/or (3) by increasing the selective pressure on the system (for example, in chemical systems, by more frequent heating/cooling or wetting/drying cycles).
- A deeper understanding of the generative forces behind the creation and existence of complex phenomena in the universe, and the role of information in describing them.
- An understanding of life in the context of other complex evolving systems. Life shares some conceptual equivalences with other complex evolving systems, but the authors point to a direction for future research, asking whether there is something distinct about the way life deals with information on functionality.
- Helping to find life elsewhere: if there is a demarcation between life and non-life that is linked to the selection of function, can we identify the "rules of life" that enable us to distinguish this line from the rest of life? biotic demarcation in astrobiological research ?
- At a time when the evolution of AI systems is a growing concern, a predictive law of information that characterizes how natural and symbolic systems evolve is particularly welcome.
The laws of nature - motion, gravity, electromagnetism, thermodynamics, etc. - codify the general behavior of various macroscopic natural systems in space and time. The "law of increasing functional information" published today complements the second law of thermodynamics, which states that the entropy (disorder) of an isolated system increases with time (and heat always flows from hotter to colder objects).
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