The existence of life in a universe that naturally trends toward disorder is a long-standing paradox. Living systems, from single-celled organisms to complex animals, are highly organized structures that maintain a low internal level of randomness. This apparent contradiction led to the conceptual idea of “negative entropy” as the mechanism by which life sustains itself. Life does not violate the universal law of increasing disorder but rather uses a continuous exchange of energy and matter to create local pockets of order.
The Universal Tendency Towards Disorder
The tendency of all natural processes is to move from a state of order to a state of disorder. This principle is governed by the Second Law of Thermodynamics, which describes how energy transformations always result in some energy becoming unusable for work. Consider simple, everyday examples like a cup of hot coffee cooling down or a drop of food coloring spreading evenly through water. These processes are irreversible and demonstrate the universe’s natural progression toward a state of equilibrium and uniformity.
The measure of this disorder and the unusable energy within a closed system is called entropy. When an ice cube melts, the highly ordered solid crystal is replaced by a more random arrangement of liquid molecules, increasing the system’s entropy. While energy is conserved according to the First Law of Thermodynamics, its quality degrades, becoming less concentrated and less available to perform work.
A closed system, such as the entire universe, can only experience an increase in total entropy, moving toward maximum disorder. This means that any process that creates order in one place must inevitably generate a greater amount of disorder somewhere else. Life, characterized by its high degree of internal organization, therefore seems to challenge this universal tendency toward increasing randomness.
Defining Negative Entropy and Its Conceptual Origin
The term “negative entropy” was introduced as a conceptual tool to address the mystery of biological order, rather than a physical reversal of the universal law. Physicist Erwin Schrödinger popularized this idea in his 1944 book, What is Life?. He observed that living organisms must continually “feed upon negative entropy” to maintain their highly ordered state and delay the inevitable decay toward thermodynamic equilibrium.
Schrödinger later acknowledged that the technically accurate term for what life consumes is free energy, but he chose “negative entropy” for its conceptual clarity. This framework suggests that an organism’s ordered structures are sustained by an influx of orderliness from the environment. The complex, highly organized molecules an organism ingests, whether as food or sunlight, represent a state of low entropy.
The idea evolved into the term “negentropy,” coined and developed in the context of information theory. Physicist Léon Brillouin linked negentropy directly to information, suggesting that information corresponds to a negative term in the total entropy of a system. A system with more specific, organized information—like the genetic code in DNA—has a lower state of entropy than a random collection of molecules. This connection highlights that order in a biological system can be viewed as a form of stored information, maintained only by constant effort.
The Biological Mechanism of Maintaining Order
The physical reality behind negentropy is that life is an open system, constantly exchanging energy and matter with its surroundings. This exchange is the mechanism by which organisms maintain a low internal entropy without violating the universal law that total disorder must increase. The organism imports highly organized, low-entropy resources and then exports high-entropy waste, effectively using the environment as a sink for its disorder.
Photosynthesis is a prime example: a plant takes in highly ordered, low-entropy light energy from the sun. It uses this energy to build complex, highly ordered sugar molecules from simple compounds like carbon dioxide and water. In the process, the plant releases heat and other forms of waste, which significantly increase the disorder of the external environment, paying the “entropy tax” required by physics.
For organisms that consume food, the process works similarly by importing complex, low-entropy organic compounds. Metabolism breaks down these ordered food molecules to release free energy, used for tasks like cellular repair, growth, and movement. This breakdown increases the entropy inside the organism, but that internal disorder is continuously exported as heat and simple waste products, such as carbon dioxide and urea. The continuous flow and export of disorder allows the organism to maintain a non-equilibrium state that persists only as long as the energy flow is sustained.