(By John Terranova)
Let me explain. . . .
Full gown piranhas are all of similar size. None get large enough to rule the others. Even as vicious predators “that will bite anything and everything” with razor-sharp teeth, they are reluctant to kill each other; instead, they “fight with raps of their tails.” Likewise, rattlesnakes, rather than bite each other, wrestle. Both species may establish a pecking order, but they do not destroy each other.
I have a theory about why they behave this way — a theory that could help make the human world more just. If one piranha, say the strongest one, were to turn his teeth upon a fellow piranha and kill it, what would happen? I suspect that all the other piranhas in the school would collectively turn upon that aggressive one and destroy it since it would be a threat to their collective safety; though that piranha were the strongest, it would be no match against the whole. Since each piranha is of similar size, none of them can become so strong and powerful that they can dominate the school.
Herein lies the model we humans should follow. . . .
Concentrated power corrupts, so it is in our best interest to diffuse power as equally as possible. If we allow individual humans to possess disproportionate concentrations of power (be it financial, political, spiritual) we jeopardize our species’ peace. Both sides of the stereotypical political spectrum tend to favor one form of concentrated power over the other. Free-market conservatives distrust concentrations of government power, yet they favor concentrations of private financial power; bureaucratic liberals distrust concentrations of private financial power, yet they favor concentrated political power. The piranha school distrusts both concentrated political and financial power, for the piranha observes that power corrupts. Need we list the innumerable abuses of power by both the private and public sectors?
I take it as a guiding principle that anyone who advocates for concentrating power is not trustworthy. Their sympathies reveal their destructive nature. We should turn upon those who valorize power and divest them of it. Rather than giving that power to another, we should destroy the power or divide the power. The more we diffuse the power, the harder it will be to take advantage of it. Kings and popes and CEOs and presidents and generals and hedge-fund managers and gurus and police captains and dalai lamas and supreme court justices and federal reserve chairmen and pastors and the like are all perversions of justice: they are piranhas that have grown too big and strong and dominate our school; they have, they do, and they will turn their teeth upon us.
 Grossman, Dave. On Killing: The Psychological Coast of Learning to Kill in War and Society. New York: Back Bay Books, 1995.