A Life Of A Thousand Years

"How broad the world is! A life of a thousand years wouldn't be enough to really know it!"

-Daggers In Darkness, CHAPTER FOUR, p. 77.

Some fictional characters live for more than a thousand years and we know who some of them are. Is it true that memory accumulation would overwhelm the finite capacity of a single brain or has it been argued that that is a fallacy? Why should the brain not simply edit out and forget its earliest or less important inputs, if necessary?

I would have two expectations of someone who had lived for a thousand years. First, they should indeed know a lot - although very far from everything. Secondly, they might have some wisdom. If knowledge is like a growing, albeit finite, circle on an infinite plane, then a larger circle has both a larger area and a longer circumference. The latter is the point of contact with the unknown. He who knows most knows how little he knows. That should be the beginning of wisdom. Apparently, the Webb Telescope is already overturning previous cosmological understanding.