There are threads over at Slacktivist and Pharyngula about the anniversary of Nagasaki, in which there's fairly intense debate over whether this bombing, and the one at Hiroshima, were justified. I stuck my nose in those threads, but I probably should have stayed out of it. Most of the debate at both places hinges on "counterfactuals." That's a bit of historical jargon. It refers to any speculation about alternate histories. Civil War buffs do a lot of this - what if Stonewall Jackson had not been killed? What if the war started in 1836? What if things had been different at Gettysburg? What if, what if, what if?
While many historians like playing these kind of games, in our professional lives, we usually stay well away from them. The problem is standards of evidence. There are no documents, no artifacts from that alternate timeline. We can't interview anyone who was there. We can only speculate. The threads at Slacktivist and Pharyngula could go on forever, if the participants are willing, because no one can ever prove or disprove speculative history. If you assert that bombing Hiroshima was wrong because there were other alternatives, or if you say it was right because other alternatives would not have worked, you can not prove your point. Your opponent can't disprove it, either - both positions are based on speculation. As issues that can not be proven or disproven aren't science, they're not history either. (Fred at Slacktivist, who started all this, bases his opposition not on speculation, but on the principle that it is always wrong to kill civilians.)
Standards of evidence are, of course, not just an issue for historians. This morning we're hearing in the news about a terrorist plot involving liquid explosives on airplanes that the British say they have broken up. I was listening to Tom Ashbrook, host of On Point, talking to Andrew Bacevich, Professor of International Relations at Boston University, about these arrests. Bacevich made the point that right now, we in the public don't know what the actual capabilities of the people arrested might have been, whether they could have in fact carried out what is reported to have been a very ambitious plot. Ashbrook is generally a skeptical, aggressive interviewer (good for him) and he immediately demanded to know if Bacevich thought the British authorities were exaggerating. Bacevich was taken aback, trying to make it clear that he simply stating a truism, that at that moment, there wasn't much the public really knew, and that indeed, the British probably don't know everything yet, either.
In effect, the British authorities are asking us to speculate about a counterfactual, about what would have happened had they not made these arrests. Clearly, we would rather speculate about plots that might have been than dissect plots that succeeded. The issue here is how the media operates. Speculation is the order of the day. Standards of evidence are out the window in many places. The talking head shows that dominate so much of cable news are heavily based on speculation. I am reminded of that poor girl who disappeared in Aruba - for a while, the cable channels, especially Fox, were in full-on, wild-eyed speculation, condemning Aruban authorities for not following up on every hair brained theory that occurred to Nancy Grace.
Speculation works to the advantage of authoritarians and reactionaries (which is most of the Republican party, these days). "Look, see, that vague impression in the ground? It might be nothing, but what if it were a bear track? We need to be afraid of the bears." Next thing you know, you're imagining a bear behind every tree and carrying a high-powered rifle - never mind that you live in downtown Cleveland. We can speculate up all kinds of scary, scary scenarios, which leads us to ever greater levels of fear. We are to be afraid, so we must throw out the Geneva convention. We are to be afraid, so we must forget our usual concerns about torture, about due process, about civil liberties, about the rule of law.
Speculating is easy. Standards of evidence take work. Fear is all to easy. Carefully weighing the evidence to find out what the real threats are is much harder, but it's the only way to keep from being blinded by fear.