Well, depends on your viewpoint, I guess. When you really get into the details, it turns out we don't "really understand" anything. We are just making more and

Well, depends on your viewpoint, I guess. When you really get into the details, it turns out we don't "really understand" anything. We are just making more and more detailed observations and then creating mathematical models of these behaviors. For example, we observe that space is curved around mass. We can model that and it helps us understand what's going on, so it's useful. We don't, however, understand what exactly is curved and what is this empty space that curves.