Adrian Bejan
(Courtesy of Adrian Bejan)
Over the last 16 years, the mechanical engineer Adrian Bejan, now a professor at Duke University, has been working on a theory for how the world works. It’s a theory of everything: how living creatures are shaped, how lava flows down mountains, how snowflakes form, how people organize our societies. It’s called the constructal law.
The fundamental idea is this: Everything that moves, whether animate or inanimate, is a flow system. A flow system “wants” to flow more efficiently, and over time will shape itself to do so. Therefore the similar shapes of tree branches and river deltas, according to Bejan’s theory, are not accidental, but the result of a flow that connects one point to a large area, with infinite points. His new book Design in Nature: How the Constructal Law Governs Evolution in Biology, Physics, Technology, and Social Organization shows how constructal law applies to power grids, the arteries and veins of our bodies, even the structures of corporations.
For Bejan, constructal law is not just a matter of descriptive science; it “defines what life means ... To be alive is to be a flow system that's free to change its configuration over time."
→ Where do you see the Constructal Law at work in the world? Tell us in a comment below.

Flow systems in action: the delta of the Lena River in northern Siberia (left)
and a cast of a human lung (right). (A. Bejan/Doubleday)
All the Trees of the Filed Will Clap Their Hands
Artist: Sufjan StevensAlbum: Seven SwansLabel: Sounds FamilyrePurchase: AmazonTen-Day Interval
Artist: TortoiseAlbum: TNTLabel: Thrill JockeyPurchase: AmazonContributors:
Jonathan Mitchell





Comments [21]
But this is also the manner in which consciousness grows and expands: radially, and by a flow that processes material from the unconscious. Jung would call that flow's dynamic integration, and the larger process of which it is a central part, individuation.
What is missing is the other protagonist in the relationship, without which our fantasies of stasis would be realistic. Constructal Law is not taking into account the interaction between bank and river, or nutrients and trees, or whatever the other whose responsive friction creates the form might be. Constructal Law describes one half of what is at least a dialogue, and in many, if not most, areas of life, an active communion.
As an architect, I came to similar conclusions on design in nature in 1995,
here's the updated review from a practicing architect and designer: http://asynsis.wordpress.com
As an architect, I came to similar conclusions on design in nature in 1995,
here's the updated review from a practicing architect and designer: http://asynsis.worpress.com
The so-called Constructal Law has been known for many years as one of a number of relations involving scaling relationships and what is known more formally in mathematics as variants of the Power Law.
Within the last decade, some excellent work in this area has been done by Aaron Clauset and Cosma Shalizi, among others.
Many interesting applications have been demonstrated and a lot of this has been done at the Santa Fe Institute, sometimes in conjunction with personnel at the Los Alamos and Sandia National Laboratories.
Two specific points are relevant. First, much of this was driven by modeling the distribution of terrorist attacks as well as related work which involved complex systems. Second, the notion of scaling relationships and exponents that one finds throughout Bejan's work and elsewhere on Power Law relations can be misleading if not done well.
Actually fitting and testing Power Law models appropriately is a critical art. Cosma Shalizi has written extensively on how to do this and how to avoid inappropriate claims, especially in fields such as physics and mathematical statistics, but also for applied models such as the models of terrorist attacks done by the Santa Fe Institute and even allometric scaling models in biology.
Just do a Google search on Aaron Clauset and Cosma Shalizi to get a good feel for the breadth and technique of this field.
I see constructal law applying to neuroscience. Instead of using methods such as dynamic causal modeling, which uses Bayesian statistics, one can PREDICT the functionality of neurons ( within a particular space as a function of time) by simply understanding the predominate forces that flow through them. This could give insight into which evolutionary braking forces caused the particular area to achieve its current structure.
i've postulated for a long time that the health of a living organism, based on water and soluble lipid material depends on the regular forward flowing nature of these media. the body is a river; keep it flowing and what is needed will be delivered; what is harmful will be taken away. BLOOD, LYMPH, INTERSTITIAL FLUIDS, WHOLE CELLS MUST FOLLOW THIS PRINCIPLE TO STAY ALIVE; WHEN THE FLOW STOPS, LIFE STOPS. a NATURAL CORROLARY TO OTHER SYSTEMS seems an inexorable extrapolation.
Swing and a miss.
The great lesson of the history of science is that most good ideas are wrong and an occasional bad one is right. This falls in the former category.
For millennia people have been trying to come up with geometric rules that govern the nature of the universe. None of those ideas survived in their pure form. People always found underlying principles that sometimes connected two things that looked the same and sometimes did not.
The platonic universe, Pythagoras's mystery schools. the crystal spheres, Kepler perfect solids, systems theory, holographic theory all suffer from the fact that they are either not predictive (just descriptive) or their predictions just don't hold up.
In this particular case,the idea just does not hold up. The most efficient flow is found in a straight line. Neither a river delta nor a lung flows optimally. (unless you want to play games with the definition of flow and optimal)
Deltas are deflected into increasing less and less efficient flows by the accumulation of sediment. Slow rivers develop greater and greater twists and sediment deposits on their inner banks. This makes them eventually twist into oxbow lakes that don't even flow.
http://en.wikipedia.org/wiki/File:Nowitna_river.jpg
Lungs show a different branching patterns to maximize internal surface area, not for reasons of optimizing flow,but for reasons of increasing surface for gas exchange. You see the same pattern of surface area optimization in the intestine (the coiling and villi) but no branching and definitely no flow optimization. The optimization comes from the need for surface area and natural selection by survival of the fittest.
In fact lungs don't even flow, there are bidirectional, oscillatory. There is no net flow at all. Birds lungs and fish gills at least are unidirectional so their is a net flow, but there is also a maximization of surface area which involves a lot of tiny little diversions making th flow less efficient.
If this guys wants a scientific theory that will have utility he has to name a set of specific principles and prove they exist. State when and when they don't apply and then go out and do experiments that show he can predict novel occurrences or inventions that follow at least stochastic rules.
This interview was inspiring from an artistic perspective. While listening I was deep in thought over how the theory branches out and touches every aspect of life and my own creative endeavors as a music writer. Further, the program evoked an emotive response and gave me a sense of peace and balance. Strange that a story on constructional law can do such a thing.
I see the constructal law as being one of the primary organizing principles in Radioheads album The King of Limbs... where musical fragmentation works in tension with a powerful sense of cohesion ... the result is flow
I see the Constructal Law at work in my own place of work... Some of my co-workers are just content just being there, pulling what I call "Under-Time" - where you do just enough to exist and there are others (thankfully enough) who seize opportunities or create them to move with (and past) the (regular) flow... and create new branches and put in more life into our organization as a result... These are exciting times.
I see the same thing happening all over the world that we cover with people just trying to break free from oppression and create new branches of life... the middle east is a perfect example... overturning California's ridiculous Proposition 8 is another...
@Arghh -- here's the music that was used in the piece:
- "All the Trees of the Filed Will Clap Their Hands" by Sufjan Stevens
http://www.amazon.com/Seven-Swans-Sufjan-Stevens/dp/B0001F7U9S/
- "Ten-Day Interval" by Tortoise
http://www.amazon.com/TNT-Tortoise/dp/B000006A97
After college back in the early '70s, I apprenticed under two old mechanical engineers for five years to learn piping design for the oil industry. I had no technical or math skills, only a fine arts education.
Instead of using standard engineering methodologies, as an artist I merely visualized molecules of hydrocarbons flowing in patterns as described in this story on Constructal law. Without knowing it at the time, constructal law helped me have a successful career designing piping systems for chemical plants and refineries in the days before computers.:-)
What's the name of the instrumental used in this piece? HELP!
An attractive feature of constructal law is that is operates at the local level.
Disregarding all this metaphysical mumbo-jumbo discussion about "Life is flow" and all that.
Even this is not so original. After all, it was the Greek Philosopher Heraclitus who coined the phrase "Everything flows" about 2500 years ago.
How is this "constructal law" so different from the principle of stationary action which is a well known principle in physics for the last, oh say, 300 years (Leonard Euler)?
Minimizing the action functional is a cornerstone of any field in physics (Mechanics, QED, Cosmology) and - gasp - it is the cornerstone of Hydrodynamics as well.
Reinventing the wheel or another scientist claiming he found the answer to life the universe and everything (I thought the answer was already known - 42) is not exactly newsworthy.
A beautiful concept. Look forward to reading book!
The path of least resistance?
I am a growth and innovation strategy consultant. I have not heard about Constructal Law before, but I have had the same observation as Bejan in the way value flows and is consumed in market systems. I am applying the thinking of Constructal Law to model markets heirarchically and identify where unmet needs and adoption factors align to drive growth opportunities in complex market systems. In fact I call the models of the markets "Value Trees" and I call the structure "Branches" or "Traunches". Measuring how well Value is being fully realized at each node in the Value Tree and the strength of factors that block or enable flow into and beyond these nodes indicates where markets are likely to reward new offerings and where they should evolve. The law works extremely well in this context, and in truth I believe it can be used to drive National economic recovery.
Listening to this show reminded me of a book I found many years ago: Ian McHarg's "Design with Nature". He is (was?) a town planner and landscape architect who developed principles of design that involved an organic/graphic process that seems to fit the Constructal Law theory. I am looking forward to learning more about the Constructal Law, thanks for planting a seed. P.S. I believe I discovered the book through an edition of "The Whole Earth Catalog", another thing that could be described as growing in a "tree-like " fashion.
Constructive Law: a law of physics
"life is a phenomenon for all systems"
The simplicity is beautiful.
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