I like this blog post, and like other commenters I agree. It's also interesting that it doesn't so much distinguish between external and internal 'achievement' so much.
For a very different take on the topic... I too was interested in the question of "measuring personal growth." So much so that I enrolled in graduate school and am now getting a Ph.D. researching personality development / change in "individual differences" over time. Another way to conceptualize / measure personal growth could be via decreases in one's level of Neuroticism over time.
What about kids? They don't seem to start with any neuroticism until they learn it or maybe the more neurotic parts of the brain start to mature/engage
Good question. We typically don't think of young kids as having neuroticism so much as an aspect of temperament we call "negative emotionality." Some children seem to have more of it than others. Taken at a slice in time, roughly half of the between-person personality variation on a given trait can be attributed to genes, the other half is environmental. (Strictly speaking, this doesn't quite account for variation in the change of traits over time though.)
Also, there's a well-studied effect where adolescents typically experience decreases in neuroticism / negative emotionality as they change and mature as they move into young adulthood.
For a very different take on the topic... I too was interested in the question of "measuring personal growth." So much so that I enrolled in graduate school and am now getting a Ph.D. researching personality development / change in "individual differences" over time. Another way to conceptualize / measure personal growth could be via decreases in one's level of Neuroticism over time.