Channel vs flow dominance – the physical basis for a constructal theory of information


In his book, The Physics of Life, Adrian Bejan proposes that the constructal flows that shape the universe are in fact “living” and that the universe is constantly evolving as directed by the Constructal Law. For convenience, I will call this Universal Evolution.

The Constructal Law was stated by Adrian Bejan in 1996 as follows: "For a finite-size system to persist in time (to live), it must evolve in such a way that it provides easier access to the imposed currents that flow through it."

We need to distinguish between Universal Evolution as Bejan defines it,  and what I will call Classical Life, the commonly understood subset of the universal, including biology, humans and technical life forms.

I will argue that the collection, harvesting and storing of energetic flows as information in order to create and express knowledge is the hallmark of life. This definition is entirely consistent with both the Constructal Law and with existing theories of life. It is demonstrably true for all life forms, from basic biology to human neural networks to the Internet and to technical life forms at all scales and mechanisms of operation.


Information as it is used here is defined as energetic flows which are sensed and stored for incorporation into knowledge. Information is an emergent property of matter and energy and is entirely dependent on the presence of a sentient receiver with appropriate contextual knowledge. Matter in the abstract can be described as having “configuration” or “state” (mass, position, velocity) but it does not inherently contain information, which is created by sensing that state and converting it to organized storage for processing or later use. We can describe things as "having information" with the caveat that it is potential information, subject to the presence of a sentient contextual receiver.  This topic is defined fully in a following article.

While replication of information is of course necessary to build a knowledge base beyond a single individual, self-replication is not a fundamental requirement for life. All manner of machines are able to receive information from the environment and use their built-in knowledge to control larger flows. The fact that they are replicated by external means (people or other machines) does not disqualify them from being considered life forms according to my Constructal Theory of Information. It’s worthy to note that some biological life forms, e.g. viruses, are incapable of self-replication but are still classified as life.


Dominance is the relative ability of one entity to cause change in another. Flow and channel are in constant tension over which will dominate. This is a key feature of the constructal Law which defines the characteristics of all information systems. In this short article, I will introduce the topic as a prelude to a larger discussion of how information systems operate in the context of the Constructal Law.

The Constructal Law admits to three possible flow conditions:

  1. Unlimited flow, zero channel dominance, e.g. a waterfall, discounting air resistance
  2. Total channel dominance, zero flow dominance, e.g. a hose or pipe. Neither of these cases creates evolution, or Universal Life.
  3. The middle ground, where flow modifies (morphs, evolves) channel and channel affects flow often in alternating balance and with potentially exquisite subtlety. In the residue from this process, we find the markers of universal evolution and the origin of information itself.

This is the universal constructal refinery that shapes and defines the evolution of the living universe. It explains how gold found its way into nuggets and how planets differentiated into layers of solids and gasses. It informs the evolution of biological systems. It is the Constructal Law in action.


When a river is in flood stage the channel patterns carved in the river bed are constantly  shifting, overwhelmed by the morphing force of the constructal flows. However, as the flow subsides, at some point the flow is no longer able to morph the channel and the channel configuration at that moment freezes out. What we see when it is over is the last moment of fast constructal morphing before the channel gained dominance over the flow.

This is the end product of the constructal flow itself, after the last of its energy was dissipated and it could no longer move the earth and rocks to give itself more room to run. In the process, the river channel has evolved into a new configuration. Until a new flow returns, that configuration will persist, frozen into the landscape. The transition point when the channel freezes out of the flow is the boundary between flow and channel dominance. This is the moment when evolution is recorded, preserving the effects of energetic flows for the future. This is where design in nature is created. Flows that pass through that channel in the future will be influenced by the form of the channel created in the past. This is the basis of all sentient information systems.


Evolution can only be recorded at the boundary of flow and channel dominance. An atomic bomb is such an energetic flow that it instantly overwhelms life forms and destroys all record of them. A petrified tree surrenders its energetic flows and channels to the flows of the evolving rock over millennia, which stores their precipitated configuration for our possible later retrieval as information. They become part of a much longer term evolution of the rocks themselves, perhaps waiting a billion years to be subducted into the mantle for the next chapter of their evolutionary story. The channel-skeletons of the petrified wood which might have provided us with information are then overwhelmed by the  energy from the molten interior of the earth and are lost forever. The Second Law prevails, even if it takes a long time.

All finite flow systems, for both universal and classical life, must evolve to survive, This evolution only takes place when the energy of the flow overcomes the constraints of the channel. If the flow energy is too large, the existing form of the channel will be obliterated. This is not a problem for universal life, as there are no “rules” or values on the evolution of the universe. If a star and all its planets gets gobbled up by a black hole, well so be it. However, it is a problem for classical life forms who have a certain affection for their continued existence.

All of the interesting action takes place around the inflection point between flow and channel dominance. This is the refinery that makes the universe what it is. This is what brings together the gold atoms for my wedding ring and makes conversation with my wife amusing.




180 million year old petrified trees at Curio Bay, New Zealand. Early in the process, flows of mineral-rich water invaded the soft structure of the tree, using their energy to morph their channel and gain access according to the Constructal Law. However, they were resisted by the cellulose of the cells in the tree. They gained access, but did not have the power to destroy the channel structure. Instead, they froze in place, preserving a “photograph” of the tree for our inspection 180 million years later.

New Zealand--2010-04-13--13-28-44--IMG_0607_©mark_heyer_2010

We can begin to understand how this works by observing constructal flows on the beach. First, the tidal flow morphs the beach channel, (part of the larger ocean-basin channel) leaving a smooth surface, but with a very even layer of fine black sand deposited on the surface as the force of the wave and tidal flows expended its energy pushing the sand uphill. It receded, surrendering dominance to the beach channel.

What we notice first about the recording of the flows is that they are complex, but not at all random.  The pattern of the channels follow physics principles which have been explored at length by Professor Bejan and his colleagues.

Gen_2009-08-09__07-28-19_IMG_6957.JPG_©mark_heyer_2009 (1)
Gen_2009-08-09__07-31-48_IMG_6967.JPG_©mark_heyer_2009 (1)

We can deduce that water flowing toward sea level in unseen channels within the sand suddenly gained kinetic energy due to a change in the slope of the beach. Soon it overwhelmed the binding forces of the sand, which defined the channel dominance of the underground flow regime. The flow morphed into a flowing river, using its newfound energy to carry away sand, dig its fast straight channel  deeper and increase access to its flow. As the slope decreased , the kinetic energy was reduced. Big sand grains precipitated out first, clinging to their brothers on the bottom and asserting their channel dominance, further spreading and slowing the flow. Soon the slowed water flows were absorbed back into the underground sand channels, and we were left with a snapshot in time of the moment the flow dominance disappeared.

Putting on our constructal geophysics magnifier goggles, when we examine the miniature valleys and canyons carefully, we find that they evolved with the largest sand grains deposited first. The flow widened laterally and slowed, creating a mesh of interacting channels, depositing graduated layers of ever finer grains. In our example, the smallest and lightest sand grains happened to be black, marking the last moments when the water flow surrendered its payload. The black sand, which started out as a uniform layer over the surface has been redistributed and concentrated in an image of the flow - a map detailing the exquisite subtlety of the flow regime - its forceful origin, its spreading and morphing of the channel (and morphing of the flow in response to the evolved structure of the channel due to previous flows) and its eventual loss of dominance to the channel. What we see, hours later while wandering the beach, is a preserved snapshot of the universal Constructal refinery in action.

This boundary - the interaction between flow and channel - defines the universal constructal refinery - which shapes and defines the evolution of the living Bejan universe.  It is the Constructal Law in action. More important for our present discussion, constructal evolution creates differentiation - design in nature, stored for the future, be it long or short. We perceive the structures and their configurations as information, which we can use to understand the world or shape the future.


This is an exquisite example of flow morphed by channel, in turn morphing channel - perfect parabolas revealed by the contrast between larger white grains and smaller black ones. At the bottom we see the very last incursion of the tidal flow, depositing large artifacts at its leading edge, exhausting its energy and falling back to leave a smooth deposition of fine black sand in its retreat. The sand itself has created a gray-scale image of the flows that created it.  Channel recapitulates flow, the basis of all information storage systems.

Classical Life

Classical life, biology, humans and technical life forms, depend on channel dominance for survival. For humans, the channel constraints are obvious - too hot, we die. Too cold, we die. Our biological channels are only capable of managing a narrow range of variation. This is true for the millions of channels which operate within biological life forms, all of them modulated and controlled by subtle and delicate information flows and channels.

However, in order for classical life forms to evolve, they need to be subjected to flows beyond their capability to control. How much beyond is a matter of the physical, behavioral and cognitive makeup of the organism. Too much and they all die. Not enough and no evolution takes place.
Further, in order for classical life forms to store information for later use, a flow must be created which “precipitates out” its flow energy as a deliberately configured physical image at theboundary of flow and channel dominance. The energy of the flow is frozen in the matter of the channel.

Think of an old audio record player. The recording was made by creating a flow (turning a blank disk under a modulated cutting head), which cut the  disk so as to increase access to the energetic flows imposed upon the cutting head. In playback, the stylus was jiggled about to recreate the energy profile of the original recording flow. Channel recapitulates flow.

The boundaries on this process are the flow energy necessary to make a “permanent” change in the storage medium - not too little, not too much. The storage medium “morphs” based on
the  flow imposed on it. To recover information, a flow is morphed by the evolved channel. In photography, silver halide crystals are “triggered” by incoming photons in a cascade reaction. Larger grains have more area and thus are more likely to be triggered than small ones. By controlling the number of photons (aperture) and the exposure time, and controlling grain size, a gray scale is produced. This is exactly analogous to the refinery function described above. We have captured and frozen an energetic and organized flow of photons.

To put it in constructal terms, an ordered flow of photons reflected from a subject strikes the film, a channel barrier, and morphs the chemical structure of the channel. In the process, the entire flow is apparently dissipated - the channel dominates, but is altered by the flow. After developing and reversing the image in printing, an unstructured flow of photons is dominated by the frozen flow channel and an “image” of the original flow is recreated. Is this an example of a constructal flow increasing access for its flows - in the future?




At extreme magnification we can see the individual grains of silver nitrate that make up the “developed” image. A very small jump indeed from the constructal flows making patterns on the beach.


The Constructal Law does not preclude the interruption or modulation of flows, nor speak to their physical manifestation, whether kinetic, electromagnetic or photonic. Using the ability of flow dominance (morphing) to induce permanent changes in its channels, and the ability of channels in turn to modulate flows, we have the physical basis for understanding the operation of all information systems within the Constructal Law.

Dominance is much in evidence in the neural networks of the brain as the balance between promotion and suppression of impulses. Many pathways, morphing constantly. Our ability to receive information from patterns of frozen flows is one of the essential characteristics of all life forms. How some flows “learned” how to create, preserve and replicate frozen flows is the key to understanding biological replication.

The contest of all life, universal and classical, is the nature of matter and its attractive forces to constrain the energetic flows of other matter which are imposed upon it. Channel vs. flow. Clues to the emergence of organized classical life are to be found at the boundaries between flow and channel dominance. This is where we should be looking to solve the mystery of the origin of classical life.

This article has provided a foundation for understanding the physical link between the Constructal Law and information. In the next article, I will begin to place the Constructal Law within the context of information systems.

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