# 42. Proof null hypothesis ## 42.1. Definition This is the concept that a hypothesis is true until positively demonstrated to be untrue. In reality, a hypothesis cannot always be absolutely proved to be untrue. This does not however mean that the hypothesis is actually true. A manipulator can use this "innocent until proven guilty" concept to demonstrate that an obviously true hypothesis is untrue, simply because it hasn't been conclusively demonstrated yet, due to lack of evidence. For instance, a tobacco producer wishes to demonstrate that their products are safe. They can easily conduct a test with a small sample of smokers versus a small sample of non-smokers. It is unlikely that any of them will develop lung cancer, and even if they do, the difference between the groups has to be very big in order to reject the pro-smoking hypothesis. But it does not automatically follow from this that smoking is therefore harmless. The test has insufficient legitimacy to reject the hypothesis that smoking is harmless but, conversely, it doesn't have enough validity to prove the truth of the alternative hypothesis that smoking is dangerous. Using the judicial concept of innocent until proven guilty, we can compare the test to a truly guilty defendant who is released just because the proof is not enough for a guilty verdict. His release does not prove the defendant's innocence, only that there is not enough proof for a guilty verdict. In other words, "absence of evidence" does not imply "evidence of absence". ## 42.2. Persistence Short to Long. ## 42.3. Accessibility Low. This is only for the well- resourced manipulator in general. ## 42.4. Conditions/Opportunity/Effectiveness Not that effective when challenged by a statistician but can be headline grabbing in the hands of a manipulator with an agenda. ## 42.5. Methodology/Refinements/Sub-species None known. ## 42.6. Avoidance and Counteraction Keep your mind open to new evidence. Just because a hypothesis is still officially un-refuted doesn't mean that it is true. It just means that the jury is still out.