Lifetime epistemic value

Suppose I discover some fact that I never end up using for anything, or even occurrently thinking about after the discovery. Now, knowledge is good. If I learn the fact earlier in life, then I will have had the knowledge for a longer period of time. So is it better for me to have learned the fact earlier in life?

I doubt it. Consider two scenarios. On the first, I learn what the capital of Zambia is just before I enter a ten-year coma. On the second, I learn it right right after I exit the coma. Learning it before the coma gives me ten more years of knowing it. But that seems a worthless gain. I conclude that in the case of non-occurrent knowing, it doesn’t matter much how long I know.

What about for occurrent knowledge? Other things being equal, if I learn some fact earlier in life, I will occurrently know the fact more times. Is that valuable?

I am less sure. But consider a daily ritual where every morning after waking up, before I am capable of any serious intellectual activity, I think to myself: Sheep have four legs. Thereby, I greatly increase the number of instances in which that piece of knowledge is being occurrently known. Again, this doesn’t seem to be worth the bother.

So it seems that neither for non-occurrent or occurrent knowledge is there non-instrumental value in knowing the thing for a longer period of time. Of course, there typically is instrumental value in knowing something for a longer period of time, both instrumental epistemic value—you can use it in your intellectual investigations of more things—and often instrumental pragmatic value.

This suggests the following. If an agent never loses knowledge, then the lifetime non-instrumental value of their knowledge depends on what they have come to know, not on when they have come to know it. The analogous thesis for perfect Bayesian agents and scoring rules is that their lifetime epistemic utility is the epistemic accuracy score at the latest point in their lives. (If we apply this to Sleeping Beauty, we are apt to get halving. But we shouldn’t apply this to Sleeping Beauty, as she forgets about her first wakeup.)

Things are more complicated in the case of agents who do lose knowledge, whether to memory loss, irrationality or misleading evidence. If we count such an agent’s lifetime non-instrumental epistemic value based on all that they have ever known, that means that if they lost knowledge of p, there is no gain to them from getting it back. But obviously they are better off epistemically if they do get it back. Things get messy and complicated now. A short-period loss in old age doesn’t seem as bad as a case where you found out something early in life and then didn’t have it for the rest of your life.

This is getting messy.