I never saw my grandfather because he had died before I was born, but I have good memories of my grandmother and of how she could play the piano at the old house.
I seem to be thinking rationally again in the style that is characteristic of scientists. However this is not entirely a matter of joy as if someone returned from physical disability to good physical health.
I would not dare to say that there is a direct relation between mathematics and madness, but there is no doubt that great mathematicians suffer from maniacal characteristics, delirium and symptoms of schizophrenia.
However I am still making the effort and it is conceivable that with the gap period of about 25 years of partially deluded thinking providing a sort of vacation my situation may be atypical.
Though I had success in my research both when I was mad and when I was not, eventually I felt that my work would be better respected if I thought and acted like a ‘normal’ person.
Statistically, it would seem improbable that any mathematician or scientist, at the age of 66, would be able through continued research efforts, to add much to his or her previous achievements.
Nowadays we can do computer experiments using Mathematica, and even solve a system of 42 equations. This offers another route to knowledge, rather than mere ideas.
But the Princeton fellowship was somewhat more generous, since I had not actually won the Putnam competition… Thus Princeton became the choice for my graduate study location.