This unusual bedform was created by the self-organizing dynamics of ocean waves, wind, sand, and shells a couple of days ago.

OK, it wasn’t. It is the work of a vacationer at Myrtle Beach. But it got me to thinking, not only about what an awesome sand sculpture it is, but about uniqueness and probabilities in Earth surface systems.

In theoretical physics, the “many worlds in one” (MWO) concept holds that, with unlimited space and time, any outcome not forbidden by the first and second laws of thermodynamics (laws of conservation of mass and energy) will eventually occur (Vilenkin, 2007 is the standard source for MWO; I encountered it via Koonin, 2012). Thus, on some beach, somewhere, some time, waves and wind have independently sculpted a sand alligator.

However, while Earth science encompasses a lot of space and time, both are quite finite. Thus, while MWO predicts formation of a sand alligator sometime, somewhere in an infinite universe with probability = 1.0, the odds for such an occurrence (without human intervention) on this particular speck of space-time (Earth) are so low as to be essentially zero.

Earth surface systems—a sand beach, a pine forest, a karst sinkhole, or whatever--generally include regular, predictable aspects in common with other beaches, forests, and sinkholes around the world, and unique, idiosyncratic characteristics associated with their specific combination of environmental factors and history. Because of this, and the dynamical instabilities and chaos that sometimes lurk within the general or universal governing laws, many, many outcomes are possible. But not everything is possible.

I agree with the MWO to the extent that the only outcomes that are absolutely, completely impossible are those forbidden by the conservation laws. However, other general laws and principles relevant to Earth make some outcomes more or less probable, and some essentially impossible. For instance, I can concede, for the sake of argument, that somewhere in an infinite universe weathered rock becomes whole again, but on our planet it ain’t happening.

Also, the specifics of geography and history at a given time and place further rule out a number of outcomes (or, from the perspective of historical reconstruction, explanations of how something came to be).  Much of my research has emphasized the idiosyncracies, individuality, and instabilities of Earth surface systems, based on the unavoidable effects of specifics of geography and history. I typically think from this perspective as geography and history providing opportunities and degrees of freedom for the variety and individuality of Earth systems. However, it is also important to recognize that geographical and historical details (at scales from molecular to planetary) also provide constraints that limit what can happen.


Koonin, E.V., 2012. The Logic of Chance. The Nature and Order of Biological Evolution. Pearson.

Vilenkin, A. 2007. Many Worlds in One: The Search for Other Universes. Boston: Hill and Wang.