Think of the many who through their 80s were cogent, even masterful. Examples include Warren Buffett, John Searle, Hubert Dreyfus, George Soros, Henry Kissinger, Clint Eastwood, and with women it’s probably even more common, and we can look to Nancy Pelosi, or indeed my own grandmother. Whatever memory slowdown there may be is compensated for by depth of experience.

Then there are those who lose it in their sixties.

In many ways it seems that ageism is one of the last acceptable prejudices.

In Biden’s case, I was struck by the difference in him before and after his son Beau’s death. It seemed like he never recovered. Charisma gone. Eyes turned beady and body stiff. Despite that he was an active and successful president (should be admitted no matter one’s politics), though unpopular.