Point (2) is what then arises. The population DOES NOT grow stronger from exposure to measles. If it did, there would by now obviously be no such thing as measles! So it cannot be the case.That is logical thinking. I know there are a lot of people around who mouth the words ‘critical thinking’ but they are merely mouthing a slogan. I am talking about LOGICAL thinking, or PLAUSIBLE INFERENCE. It is a skill not taught in our universities.