I've always had an insatiable thirst for knowledge; I love reading, school, college, studying, etc. But i've always thought; all this effort, all this knowledge, will disappear when i die. So what's the point? Its a pretty thought to think that perhaps we'll all become one after death, the whole Atman is Brahman thing, but really what's the point?
The point is everything.. Every little thing you do effects everything else. It might not be in the way you imagine, and you might not have ultimate control over the final outcome, but you still contribute. When you're dead, they'll still see you.
In the Hitchhiker's Guide to the Galaxy is written the following quote, "In the beginning the Universe was created. This has made many people very angry and been widely regarded as a bad move." I have speculated on this. Suppose the Universe is a mistake, something that isn't really supposed to be here, or, at least, not its current manifestation. Then that means that all people are going to be prone to misery, subject to the incomprehensible discomfort of the entire Universe having to deal with its lack of happiness or purpose. In that case, it means that MY reason for existing must be to try and make it as un-miserable as possible for as many people as possible. But, in order to make other people happy, I have to be happy first. So, I study, and I learn. That's fun to me, so I know exactly where you're coming from. Even though I have had the exact same thoughts as you, about the futility of learning something knowing that I will one day forget, I keep doing it because I enjoy it. I am happy, and that better equips me to go out and help make other people happy. And that can never really be a waste of time.
but how many of us will actually make a lasting impact in the future, like after our deaths? Even if we do use our knowledge to help people, how will any of it aid the future after we're gone? There's been plenty of intelligent people throughout history, how many will be remembered?
Most of us will aid the future. Most of us have children. If we dont, we at least talk to people. Help them become better. Which in turn helps their kids, helps them accomplish things. And so forth. Us little people have a big impact, although we may not be remembered, who gives a crap
It doesn't matter. There is no time but the present. As long as you are doing the best that you can, with what you have, to make the world as good a place as it can be, right now, you are doing as much as anyone could ever expect. Don't get down on yourself because you can't affect things that happen after you die. Just do the best you can right now, both to be happy and to make others happy - right now. That's the most important thing. I'm sure you've heard the quote, "Eat, drink and be merry, for tomorrow we die." Well, for you it might be, "Read, learn and be merry." Either way, no time spent enjoying what our beautiful world has to offer can ever be said to be "wasted."
I've never experienced the afterlife to know what happens to knowledge. If we do take it with us, woohoo! If we don't, we just reincarnate to do it all over again. Both scenarios sound like equal fun to me.