Earlier quoted context omitted.
How would you falsify your hypothesis that the wife's allergies are from a "too clean" environment?
You can’t, in general, test something that already happened. Moreover, given the immune system is a complex system with some degree of randomness involved, it would probably be impossible to prove that any particular person’s allergies were caused by a too clean environment. But we can certainly study it at a population level and it can be falsified with populations. This is similar to smoking. Smoking is a good expl…
So how would you falsify “the population with his wife’s allergy often get it from sources other than a too clean environment”?