I'm just confused about why he didn't followed his train of thought further (i.e. first principles thinking) on that. As I see it, people don't change their mind mainly for two reasons. One is that no compelling new information reaches them, and the other is that as people age, they have to be more conservative on their own diminishing energy, which affects them in multiple ways (avoiding the challenge of their current beliefs, which can be tiresome and not that necessary compared to someone younger that has to find out more about the world in order to grow and gain competence; or increasingly limiting the circle of people that is one's idea exchange medium, which can devolve into something where politeness becomes more important than other things; etc.), then there is just the custom of leaving the elderly be as their change is not worth the cost. (On the last one it's not only the elderly, as many aspects that people give up on attempts to "fix" each other starting from much earlier ages.) Now, if only that aging and age related energy decay could be solved, there would be an entirely new game, looking for a new homeostasis! ...or maybe one has to be young enough to be curious enough about something like this?