# Dinner Discussion: The New Constructal Law of Nature

Updated on September 25, 2012

## Existing Laws of Physics: a brief overview

Just a quick refresher in case high school is a distant memory:

Newton's Three Laws of Motion: These describe what we know about how objects act on each other. By which I mean they help us kill at pool. Or they would, if in addition to the precise knowledge of acceleration, force, and mass, they also conveyed the ability to effectively hit a ball with the tip of a stick. Sadly, this is not the case.

The Law of Gravity: Describes the attractive force between two objects of sufficient mass.

Conservation of Mass and Energy: This is the law behind E=mc2, which basically states that the total amount of energy in a closed system is constant and that mass, as a manifestation of energy, can be transformed (i.e. through nuclear reaction) into energy.

The Invariance of the Speed of Light: Yes, the speed of light in a vacuum is constant. It bends, too.

## Constructal Theory: the law and its implications

The Constructal Law suggests that the design of all moving objects (both animate and inanimate) follows the same developmental patterns. It is, essentially, a scientific explanation for a phenomenon that has long been used in support of the 'intelligent design' theory.

However, the design we've come to recognize in trees, rivers, lungs, and blood vessels is not just found in nature: it's heavily prevalent in the built and social/corporate environment as well, most clearly in our transportation networks and in corporate structures. The uniting factor is ease of flow: our blood vessels have developed in the pattern necessary to maximize the efficiency of our circulatory system. And our roads, likewise, have developed in the same pattern to maximize the efficiency of our travel - crappy drivers and rush-hour traffic notwithstanding. Everything which moves (through time and space, living or otherwise) is a flow system which has evolved to facilitate movement. Ta da!

Yes, it's simple. Elegant and simple; elegant in its simplicity. Thus adhering to Rule No. 1 of physics. It also adheres to my personal rule: For pity's sake, no math.

You can write it on a flashcard: "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." It is a statement of a natural tendency, and one that is readily recognizable in our existing knowledge of How Stuff Works. My new favorite game is to try to see how it applies to whatever comes up in daily life: file sharing, writing, teaching, research. And it's there! Find it!

The Law is meant to account for all evolution and all design in nature, so the "tree pattern" (or lightening pattern, or circulatory pattern, or river pattern...) is just one small part which describes the form taken whenever the aim of the flow system in question is to move something (for example, electricity) from one point to another. However, the law is more broadly concerned with the efficiency of movement, so different patterns are associated with different kinds of flow systems. Consider, for example, ice bergs at sea which without fail orient themselves perpendicular to the air current so as to facilitate the transfer of movement from wind to water. These are all phenomenon with which you are probably familiar: the law simply puts a name to it, for efficiency's sake.

How sweet.

As for broader implications (and possible topics of dinner table discussion), some argue that it changes our understanding of what it means to be alive. Which, I rather hope, is something we are all at least a little bit interested in.

It also could be said to suggest that no flow system is ever complete: there is no definite solution or conclusion. This might be one of the biggest challenges to the religious underpinnings of the intelligent design theory.

## The Man Behind the Idea and the dude who made it accessible: Meet Adrian Bejan and J. Peder Zane

Adrian Bejan, a professor of mechanical engineering at Duke, is among the most often cited authors in engineering world-wide. His research, prior to developing the constructal law, ranges from thermodynamics, heat transfer, and fluid mechanics to convection and porous media. His undergraduate and graduate work was all done at M.I.T., so there's a pretty good chance that he used to go for runs along the Charles River.

Among his many awards and honorary degrees (the man has something like 16 of them, for crying out loud), I was particularly struck by a repeated phrase: several of his awards were granted for "original and unorthodox ideas" or "significant and unconventional contributions". He's a well-regarded maverick! I kind of thought Sarah Palin killed that word, but I hope that Professor Bejan can redeem it. Incidentally, he has had two (!!) principles named after him: Bejan number (Be) was proposed as the name for the dimensionless pressure difference group in forced convection, and (also in convection) for the dimensionless ratio of fluid friction irreversibility divided by heat transfer irreversibility.

Basically, he's the Batman of dimensionlessness in thermodynamics and convection.

Bejan's co-author, Mr. Zane, is an Assistant Professor of Journalism & Mass Communications at St. Augustine's (NC) and possibly the fellow who made the book readable (having groaned through plenty of science writing by scientists, I can only imagine how unreadable it could have been). Given that my initial research turned up facebook and linkedin profiles, I'm guessing he's the more personable of the pair. I feel duty-bound to point out that although he is the CEO of an editing company, he misspelled "Assistant" on his facebook profile. And for anyone who wants to go on a treasure hunt, he also has a mismatched verb tense in his linkedin profile. Pedantic copy-editors unite!

In any case, I fondly remember the columns he wrote for the News & Observer and do recommend looking them up.

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• Kevin M Behan

6 years ago

I would like to call attention to an article I wrote for Psyche Today blog which connects the Constructal law to the phenomenon of empathy in dogs.

http://www.psychologytoday.com/blog/my-puppy-my-se...

• AUTHOR

buckleupdorothy

6 years ago from Istanbul, Turkey

That sounds like an amazing avenue of inquiry, Kevin! Let us know when you publish - I would love to read it. What a great application.

• Kevin M Behan

6 years ago

I'm applying the Constructal law to the mind of animals in general, and dogs in particular, given what I've learned as to how canines self-organize for the purpose of flow. I have a website under the constructal canine mind and I believe that in addition to understanding the function of neurology, the Constructal law is one way by which one can go deeper and actually divine how they perceive. In response to "Wilderness" comment above, in my view the mind of man and any of our cognitive doings do not fall outside the Constructal law either. For example, if a change isn't going toward optimizing flow, it increases an emotional charge and sooner or later someone will come along and improve upon it. I think Bejan would say, it's in our nature.

• AUTHOR

buckleupdorothy

6 years ago from Istanbul, Turkey

Thank you, Robin - I'd love to read about this from an architectural perspective. It seems like the tension you describe is absolutely fundamental to the whole process.

6 years ago

Nice take on Constructal Theory, love the Batman comment. As an architect who had similar insights back in 1995 (revised and republished last year), I'd like to think I'm Robin and here's why: the "persisting in time " is feedback-led (archetypal self-similarity), while the "easier access to flow currents", is the principle of least action and optimisation/energy minimising. There's some beautiful geometries that emerge from this dual process, which can be explored by searching Asynsis: asymptotic synthesis.

• AUTHOR

buckleupdorothy

6 years ago from Istanbul, Turkey

That's all very true - and from what I've read, Bejan's answer is that all change is not necessarily in this direction - rather, it's the changes that stick that adhere to the principle. This makes it much harder to argue with, unfortunately, since anything that seems to disagree with the law can be explained as flux - trial and error.

• Dan Harmon

6 years ago from Boise, Idaho

Seems to me that law makes good sense and is descriptive of how nature works. It often fails, however, when man enters the picture.

Electrical wiring, for instance. Consider the flow of electrons down a wire, and how that wire should be routed in an efficient manner to facilitate that flow. It very often is not, though. It follows building lines instead of making the shortest path. It is as small as possible while still providing the power to operate, regardless of efficiency. The wire often makes large detours caused by changes in building design.

Very often these are simply for man's notion of aesthetics. Or it can be for lower initial cost or for ease of installation. Very seldom is the path a wire takes during construction of a building primarily based on electrical efficiency, i.e. improved flow characteristics.

This follows man's work everywhere he goes. Design of an office layout will put desks and file cabinets far apart for aesthetic reasons - to put the desk by a window, perhaps, when the file cabinet should go there to facilitate the flow of traffic to and from that cabinet.

Nature, of course, doesn't care about aesthetics; it cares almost solely about function and the law generally works very well there.

• chelseacharleston

6 years ago

Cool synopsis!

• Sandra Busby

6 years ago from Tuscaloosa, Alabama, USA

Hmmmm! My kind of stuff, although I can only skirt around the edges. Thanks for SHARING.

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