I don't know that a "fruitful life" is something that can be objectively defined, so I don't know that there is anything to measure statistically. Also certain

I don't know that a "fruitful life" is something that can be objectively defined, so I don't know that there is anything to measure statistically. Also certainly talent matters, but inspiration (real inspiration) is important to long-term productivity. For example I have a friend who had serious issues working and typing due to old neck injuries. She became inspired to look into the connection of bows to Old Norse mythology and in the process not only typed a long written work (she's now working on a book) but took up bow-making and made several original contributions to my own understanding of some of the connections. None of this would have been possible for her if it were not for this inspiration. Similarly when you look at people like Linus who can code all day every day there is a certain level of inspiration that's required to do this without burning out. I also know that when I am in an inspired mood even hard problems are easy, but when I am in an ordinary mood, hard problems can be hard......