No, wisdom and knowledge don't correlate linearly with time. Wisdom and knowledge come from insight, reflection and experience. Sure the 40 year old has most likely seen more and done more than the 20 year old, but that means nothing if he does nothing with what he has seen, and just seeing these things does not impart anyting but the most shallow definition of wisdom on a person. I've met 40 year olds far wiser than most 80 year olds, and I've meet 20 year olds far wiser than most 40 year olds. The length of time someone has been alive is not a valid excuse for dismissing what they say or the insight they've developed. Life is a subjective experience and the length of time involved means very little compared to what they've experienced and what they've gone through.
As my dad taught me, some people get twenty years of experience and some people get one year of experience twenty times.
But the letter title was interesting to me: in Silicon Valley where I work, there are engineers who enjoy doing things and engineers that seem to have some big plan to become famous and rich. The former are a lot happier and usually more successful over the years.
Not sure where you read anyone saying wisdom and knowledge correlate linearly with time, the parent poster definitely didn't say it. Other than that, I agree with your post, but know that you can pretty much straight substitute "experience" and "time."
