I've recently come back to a story I had started some time ago and have started to develop quite a few questions about how we view time. This is likely to be the first in a small series.
Our fictional creation contains humans in large numbers, but no other beings or existences. Due to the extreme time span this is likely to encompass you can consider anything +-1000 years from current humans.
Within this world also exists our special use case who just so happen to be our main cast. Let's call them Group B
Members of group B by definition live their first life as completely normal humans. They are raised in line with the beliefs and people of the time. There is absolutely no design or belief that they are any different. And, indeed, from a physical perspective they are no different.
Upon dying, from natural causes or otherwise, members of Group B wake up on the prime plane. At this point in time they are now fully awakened and functionally immortal.
- They cannot die from old age and do not age.
- They cannot die of starvation in any form, and only consume food as a consequence of enjoyment.
- They do not die when any subsequent life is ended
- They can die from having their real body killed.
Now, members of Group B can and do often (It's pretty much their purpose) create for themselves new lives on other planes. They have the ability to fabricate an existence and begin life in that existence, returning only when the pseudo life has ended. They maintain any memories from this life, including memories they created for time before they assumed the life.
With all of the details out of the way, I find myself beginning to question a few of the constraints. With things as they are, it is completely within the range of expectations that members of Group B may go between dozens and hundreds of years between seeing each other. What I am left with now is a bit of a conundrum.
How long would a newly minted human have to live before hundreds of years seems like hardly any time at all, if it can even happen?
Note: As a baseline, I am looking for being able to remember or continue a conversation that happened ~200 years prior from their frame of reference. Never is a perfectly acceptable answer. Going into this question I realized the possibility that humanity is just not capable of keeping memories alive for that long.