The Science of Existence (53) Constructal Law

Constructal Law

The Constructal Law is a universal tendency toward design in Nature, in the physics of everything. This tendency occurs because all of Nature is composed of flow systems that change and evolve their configurations over time so that they flow more easily, to create greater access to the currents they move. ~ Romanian American mechanical engineer Adrian Bejan

Constructal law states that flow favors the path of least resistance. Any system, whether inanimate or alive, evolves to optimize efficient transport.

Constructal law is a tenet of all design and evolution in Nature. It holds that form arises to facilitate flow. Essentially, constructal law is a statement of energy economy shaping structure.

Tree structures – from lightning bolts to circulatory systems – are ubiquitous because they optimize the flow of energy or material from source to destination. (The concept of destination involves a teleology when actions have an intended end. Lightning, for instance, seeks an outlet of discharge.) Alternately, as with plants, a tree structure affords ideal access flow – of sunlight and air.

The essential properties of water create the affinity for drops to coalesce and flow together in following gravity. So, streams flow into rivers, which invariably lead to the sea. The flow is more than mere topography.

Constructal law can be construed as a patterning mechanism for gyres. Constructal law is as readily applied to optimizing the arrangement of cells and organs as it is to cosmological components, from planets and star systems to galactic structures.

Constructal law also applies to economic and social systems, providing the basis for viewing exploitative corruption as a natural tendency: that wealth accumulation, and sustained poverty, are Nature’s way of just desserts.

Nested hierarchical networks of systems are pervasive: from cells to ecosystems to social interactions. Hierarchies afford optimization of communication and controlled energy flow.

Both biological evolution and cultural evolution operate under a number of deep constraints. The majority of webs display a balance between integration of multiple signals and control over multiple targets under a bow-tie structural pattern. ~ Adrian Corominas-Murtra et al

In a bow-tie structure, a diversity of inputs (fan-in) are processed via a limited set of protocols, with various resultant outputs (fan out). Bow-tie architectures often appear in complex and self-organizing systems ranging from biology to technology. Bow ties provide heterogeneous stimulus-response via orderly processing. In operation, bow ties often mediate tradeoffs between efficiency and robustness.

Constructal design applies at every scale. Hence, constructal law stipulates a hierarchy of coherence at every level of existence.

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. ~ Adrian Bejan