REFERENCE: Eugene Robinson, "Sadly, the carnage will never cease," Ventura County Star 3 October 2017: 13A ; "The carnage will continue," The Washington Post, 2 October 2017
Eugene Robinson will get corrected frequently for his assertion that Stephen "Paddock was using a fully automatic rifle" in the massacre on the Las Vegas Strip on Sunday, October 1, 2017. Apparently Paddock had instead a number of legal semi-automatic rifles with legal "bump stocks," that in the words of Lisa Marie Pane of the AP "allow a semi-automatic rifle to mimic a fully automatic weapon by unleashing an entire large magazine in seconds" and were all he needed for his point-and-spray approach to marksmanship with human targets.
I wish to correct a less technical assertion in Robinson's fine column: "There can be no rational motive for mass murder"; unfortunately — tragically and worse than tragically — here Robinson is wrong. Mass murder is always and necessarily evil, but it can be the result of rational — measured, calculated — choices.
If you're one Great Khan or other and have united the tribes on the Eurasian steppe and need to keep them united and producing income and not revolt, it is rational to set them moving into China and Europe. With Genghis Khan, the most impressive of the lot, the project killed some forty million people.
If you've come from Europe to the New World to kill and conquer for profit, and you come across a mountain of silver and cities rich in gold, and if the local inhabitants are only lightly armed and frequently just die off from diseases you survived as a child — then it is rational to do what you came to do and enslave and kill as best calculated to maximize profit. An occasional Jesuit might ask you rhetorically, "What shall it profit a man if he gain the whole world and lose his soul?" (Mark 8.36), but you can answer, "He gains the world, father," and as long as you keep sending back to your royal masters a big portion of the loot, and convert some of your new slaves to the true faith — you won't get into trouble in this life.
Or if you're in California for the 1849 Gold Rush or in the Congo Free State for ivory and rubber around 1900 and you've been brought up as a committed or casual racist, then push the locals off any land you want or reduce them to serfs — or "Exterminate all the brutes!"
The belief in evil is dangerous, especially believing in it as an absolute that allows you to judge guilty whole cultures for celebrating murderous conquests or slavery or female infanticide; "Evil" is a necessary concept, however, precisely so you can condemn mass murder (etc.) as evil and not have to fall back on calling irrational a tactic well calculated to fulfill one's greed or lust for power and fame.