There are things we know we have yet to discover and we are currently looking for an answer to it. For example, the cure for cancer or whether or not there is life outside earth. These are things that human kind has been in search of for many years and we still have not figured it out yet but there are many other more ideological things that we have not discovered yet. For example: word peace. We have yet to create a world where humanity is united as one. A world without war and hatred where everyone is equal. Whether or not this is a possibility is debatable, but by now we should have been able come up with some kind of way to solve our problems without the use of violence.
Lastly, and I think most importantly, we have not figured ourselves out. As high school seniors, most of us don't know what we want to be in life or what we want to study. Some of us don't even have a slight idea of things we like or things that intrigue us. These are things that we don't know now, but will eventually figure it out. There are, however, some things that we don't know now and we may never find out. Like what the purpose of life is, or what life after death is like. There are religious beliefs that answer these questions but there is no solid answer to it, they're more like opinions. These things we have to find out for ourselves and create our own opinion for because no one will be able to give us a straight answer to it.