Back when I was in a class about criminal justice statistics, the professor asked the class whether theories or facts were more important. Most of the class responded that facts are more important because theories can be wrong; facts are facts.
“No,” said the professor, “if all you have is a bunch of facts and no theory, then you can’t explain social phenomena.” In criminology, there are a lot of statistics, such as the fact that the US has the world’s largest incarceration rate of about 762 incarcerated per 100,000 population. If you have no theory of why this is the case, then you don’t have much basis for explaining why an alternative policy would reduce the incarceration rate (unless, of course, it’s simply to let everyone out, but I think you get my point). So, theories are supposed to explain causal factors that lead to the facts and statistics we have.
Another important quality for a theory to have is that it be possible to disprove it. I believe that Keynesianism, as presented by proponents like Paul Krugman, fails in this regard, particularly fiscal stimulus. Despite the fact that the Japanese and US governments have spent trillions in stimulus packages, they both have economies that haven’t fully recovered and still have high unemployment numbers. Yet Krugman always seems able to rebuke any doubts cast on his theory by saying, “The stimulus wasn’t big enough,” or “Without the stimulus, things would have been worse.” Essentially, it’s not possible to disprove these statements empirically: we don’t have a time machine to go back and try a stimulus that Krugman would declare big enough, or to go back and take the stimulus away and see what happens. Thus, Krugman and his theory always have an escape plan.
Similarly, it seems that the theory behind advocacy of gun control is also non-disprovable. Think about the shootings that gun control advocates use as reasons why there should be more gun control measures: the Aurora theater, Sandy Hook Elementary, Tuscon, Columbine, etc. Almost all of them (with the exception of the shooting in Arizona), occurred in an area where no guns at all are allowed or concealed carry is prohibited. Indeed, had anyone shot back at the shooter in the Aurora theater, he or she would have been guilty of a felony. And yet largely the policy response to these incidents is not “Gun control totally failed to prevent these situations,” but that there isn’t enough gun control.
So my question is this: what exactly would it take, or what would have to happen, for a gun control advocate to say, “Hmm…I guess gun control doesn’t decrease violence.” It is my suspicion that anything short of full civilian disarmament (or maybe they’ll let you have a muzzle-loader or two) would not be enough; any shooting incident still occurring would be evidence that further gun control is needed.