Old And Wise

If we were blessed with an indefinitely prolonged lifespan, then we would have to use it to become wiser. Do Poul Anderson's Hugh Valland and Hanno do this? Our view of what counts as maturity would have to change. Currently, it just means being able to function in this society without being locked up or declared insane. Society would have to change somehow to accomodate longer-lived people.

James Blish's John Amalfi thinks that he is maturing after two thousand years. About people in general, he reflects:

"A short lifespan leads to restlessness; somewhere within the next few years, there has to be some El Dorado for the ephemerid. But the conquest of age had almost eliminated that Faustian frenzy. After three or four centuries, people grew tired of searching for the unnamable; they learned - they began to think of the future not as holding a haven of placidity and riches, but simply as the realm of things that had not happened yet. They became interested in the budding, the unfolding present, and thought about the future only with an attitude of indifferent acceptance toward whatever catastrophe it might bring. They no longer burned out their lives seeking catastrophe, under the name of 'security.'
"In short, they grew a little more realistic, and more than a little tired.
"Amalfi waited with calm confidence."
-James Blish, Earthman, Come Home IN Blish, Cities In Flight (London, 1981), Chapter Seven, AT pp. 422-423.

In Anderson's World Without Stars, immortals either explore the universe or settle into timeless unity with one planet.

Robert Heinlein's Lazarus Long thinks that:

his first two and a half centuries have been his adolescence;
as yet, Earthmen have had the capacity but not the time to tackle important questions;
after about five hundred years, he will know how to tackle them.

Of Brian Aldiss' characters, one thinks that he should refuse immortality because he is not mature enough whereas a group that is already immortal works in secret to increase its own power - of course.