21 June 2016: The Orlando nightclub shooting, or something similar, may have been inevitable

When confronting a tragedy such as the Orlando nightclub shooting, we routinely search for specific reasons why this incident occurred.  However, I believe that an event such as this may have been inevitable, and is best understood not by focusing on specific facts associated with the gunman, but by understanding features common to mass shootings in general (see, for example, New York Times 12/3/2015, Washington Post 6/13/2016).
In 1987, Danish physicist Per Bak introduced the term “self-organized criticality” (Physical Review Letters 1987;59(4)), a property of complex systems that emerges from simple local interactions, independent of the details of the process.  In his book, How Nature Works, Bak indicates that there is a “tendency of large systems with many components to evolve into a poised, “critical” state, way out of balance, where minor disturbances can lead to events, called avalanches, of all sizes” (page 1).  Events that are minor or catastrophic surprisingly have the same basic cause.  They occur not necessarily because of a specific outside force, but are due to the dynamic interactions of the individual components of the system.
Bak illustrated self-organized criticality by a child dropping grains of sand.  Initially, the sand merely accumulates into a small pile.  Later, dropping one grain of sand may lead to a small avalanche in the pile.  At some point, dropping another grain of sand may lead to a “catastrophe”, an avalanche involving much of the pile of sand.  Thus, it appears that the grains of sand, without any outside assistance, have organized into a delicate state where a minor disturbance may cause a catastrophe in the pile.  This catastrophe occurs for no particular reason.
Bak found that systems that exhibit self-organized criticality have a power law distribution (frequency of events), represented on a graph by a long tail, which looks much different than a Bell curve.  For the mathematically inclined, on a "double logarithmic graph", the result is a straight line.  It is called a power law distribution because as a mathematical equation, one variable is a power of the other.
Bak found that earthquakes were examples of self-organized criticality, and follow what is called the Gutenberg-Richter law.  For every 1000 earthquakes of magnitude 3 on the Richter scale, there are about 100 earthquakes of magnitude 4, 10 of magnitude 5 and 1 of magnitude 6.  We are much more interested in what causes larger earthquakes, but in fact “large earthquakes do not play a special role; they follow the same laws as small earthquakes" (page 14).  

It has been suggested that crime, in general, also follows a power law distribution:  "A vast majority of the population commits little to no crime, with only a small percentage of the population committing any crime. Moreover, an even smaller percentage of the criminal population commits most of the crime. Similar results are found when examining the places in which crime is committed." Tim Hegarty, "Power Law Distribution and Solving the Crime Problem," The Police Chief 77 (December 2010): 28–36.  See also Cook et. al., Scaling Behaviour in the Number of Criminal Acts Committed by Individuals, 2003.
I am not aware of any specific study examining whether mass shootings are an example of self-organized criticality that follows a power law distribution, but it might be true.  If so, then our efforts at preventing terrorist activities on the scale of the Orlando tragedy may best be focused on preventing all mass shootings, not just focusing on the ones that make the headlines.