This explanation may help. I call it the "frontier effect" in development. It was taught to me by an old scientist. Life is a frontier if you keep moving. As

This explanation may help. I call it the "frontier effect" in development. It was taught to me by an old scientist. Life is a frontier if you keep moving. As you progress in life you have fewer yardsticks to judge yourself against. At kindergarten we all chant in unison. By middle school you follow what the teacher says, but some people learn differently. It's probably the last "Standardised" (SAT) test you ever take. At high school you are expected to read books by yourself and you choose different books than others. By university it's mostly hands-off, and only the lectures are common amidst diverse self-study. At PhD you know everything about a vanishingly small field, and by definition the doctoral graduate is the singular world expert on their tiniest corner of knowledge. Each of us on a journey from a common place to a unique viewpoint in life, that can be quite lonely. Regardless of whether you follow an academic path I think this applies to everyone. At the start it's easy to see how you measure up to others. By 40 you need to work hard to find smarter people to challenge you and you're not sure where you stand. You see that being smart or confident isn't all that, and it ruins some people. You see people you thought were smart do really dumb things, and people you considered below you race ahead by making wise life-choices. I like the article because it hints at an important truth, that you can simultaneously be too self-assured and not enough. Our value systems for judging ourselves are weak in this society. But as the objective clarity of that sweet spot wanes, something else kicks in as you age, which is a kind of contentment/wisdom. You care less about where you stand and are comfortable with mistakes. A few regrets adds character. Financial or institutional success are no longer good indicators as you start to turn to more spiritual ways of knowing where you stand.