Rule #4: Learn how to defend against the Stalin Argument.
Any atheist who has dealt with Christian supremacists for long enough has encountered the Stalin Argument. It goes like this: “Stalin was an atheist, and he killed 20 million people, making him history’s greatest butcher. Atheism has killed more people than religion.” Some Christian supremacists falsely claim that Hitler was an atheist, and add him into this argument as well, but that one is easily refuted (all of Hitler’s anti-Christian quotes are uncorroborated claims from third-party sources, while Hitler’s pro-Christian quotes are in Mein Kampf, which is indisputably authentic, and the German people, who enthusiastically supported Hitler, were definitely Christian). In any case, returning to Stalin, can you spot the logic problems here? Let’s go through them one at a time:
1) False Cause Fallacy (specifically, assuming that coincidence = causality): if you claim that Andrea Yates’ religious beliefs led to her terrible crime (she drowned her own children), a Christian supremacist would immediately point out that her Christian faith and her crimes are not necessarily connected just by virtue of cohabiting in the same person. Why do they not see that the same is true for Stalin and his megalomania? Stalin never even claimed that atheism had anything to do with his policies, unlike Andrea Yates who actually did claim that her religious beliefs led to her actions (she even explained how; apparently, she wanted her children to enter Heaven in a state of grace, before being corrupted by the materialistic and sinful world).
2) Strawman Fallacy (specifically, assuming that atheism teaches personal conduct): in order for Stalin to be motivated by atheism, atheism would have teach a code of behaviour, just as religion does. In fact, that is not true at all; atheism does not have any particular set of moral teachings. It is merely the absence of a particular kind of belief, and as such, it does not tell you how to live. When someone claims that Stalin was motivated by atheism, he is implicitly assuming that atheism actually teaches people how to live and what to do. In fact, it does no such thing. By pretending otherwise, Christian supremacists are grossly misrepresenting what atheism is. In reality, atheism is not a religion. It does not tell you how to live, or who is good or who is evil (or even that there is such a thing as good and evil), or who you can marry, or when you’re allowed to have sex. Let’s put this another way: Christians do not believe in Zeus; does disbelief in Zeus motivate them to do anything in particular, other than resist when people try to make them worship Zeus? Of course not. So why should disbelief in God motivate anyone to do anything, other than resisting when people try to make them worship God? Since atheism has no moral code of its own, an atheist could be a communist, a humanist, an objectivist, a utilitarian, or a subscriber to any number of other moral value systems.
3) Complex Cause Fallacy (chalking up the unprecedented size of 20th century death tolls to belief systems alone): While warfare reached unprecedented heights of destructiveness in the 20th century, it is an example of the complex cause fallacy to assume that this was due to belief systems alone, and not other factors. One rather obvious alternative cause is improved technology: humanity’s methods of killing reached new heights in the 20th century, thanks to the development of aerial bombing, nuclear weapons, mechanized logistics, modern artillery, etc. Historical butchers like Napoleon, Julius Caesar, Genghis Khan, and Alexander the Great were utterly ruthless, but their death tolls were limited by the technology available to them (not to mention the limited size of populations in their day).
4) Ignoring proportions: following from the previous point, the huge death tolls of 20th century warfare, while shocking and unprecedented in sheer magnitude, are not proportionally unprecedented. You can’t look at numbers without looking at the size of the population they come from: one hundred murders per year in a city with a population of 5 million are proportionally far less than five murders per year in a town with a population of only 20 thousand. In 1940, the population of the USSR was roughly 190 million people. If we were to accept the popular (but most likely exaggerated) estimates of Stalin killing at least 20 million of his own countrymen, that adds up to a bit more than 10% deaths: a horrible figure to be sure, but nowhere close to what Julius Caesar did in his conquest of Gaul, where he was estimated to have exterminated roughly one third of the population of Gaul. Not to mention the fate of the Native Americans, whose population was reduced by more than 95%: a truly incredible death toll the likes of which we rarely see in history, and which was definitely perpetrated by Christians.
5) Inaccurate Data: the “20 million dead” figure has been widely reported, but it was reported at a time when western scholars had almost no access to actual data from behind the “Iron Curtain”, so they engaged in a lot of speculation. After the fall of communism, much more data has been made available, and scholars have revised their estimates downward. For example, estimates of Ukrainian famine deaths have been lowered from 12 million to 2-4 million. Meanwhile, Russia lost at least 25 million dead to Nazi Germany during World War 2. If we compare Stalin to Hitler, Hitler has a much larger death toll, so the claim that Stalin is history’s greatest butcher is false (even if we ignore point #4 above). It’s also worth noting that Imperial Japan’s butchery of Chinese civilians (estimated at 12 million dead) is usually ignored when making these comparisons, and that both Nazi Germany and Imperial Japan were religious (Hitler even appointed himself head of the church).
The more thoughtful Christians usually don’t use the Stalin Argument, but Christian supremacists always use it, so it would behoove any atheist to know it in advance, and be ready for it.