At the heart of quantum mechanics is a rule that sometimes governs politicians or CEOs-as long as no one is watching, anything goes.
Hardly a pure science, history is closer to animal husbandry than it is to mathematics in that it involves selective breeding. The principal difference between the husbandryman and the historian is that the former breeds sheep or cows or such and the latter breeds (assumed) facts. The husbandryman uses his skills to enrich the future, the historian uses his to enrich the past. Both are usually up to their ankles in bullshit.