What exists in the universe? And how do we come to know these things? Better yet, how do we know anything? To get to a point of greater knowledge, to which direction should we turn, and what methods can we use to move there?

What exists in the universe? And how do we come to know these things? Better yet, how do we know anything? To get to a point of greater knowledge, to which direction should we turn, and what methods can we use to move there?