In The Boy in the Striped Pajamas, according to Bruno, what are the two categories of discovery?

In Chapter 10, Bruno walks for almost an hour along the fence at Auschwitz and is just about to turn back and head home, when he sees a small dot appear in the distance. Initially, Bruno thinks that he may be looking at a mirage, but as he gradually walks closer, it is revealed that Bruno is actually staring at a young boy. Bruno had read enough books to realize that explorers could never be...

In Chapter 10, Bruno walks for almost an hour along the fence at Auschwitz and is just about to turn back and head home, when he sees a small dot appear in the distance. Initially, Bruno thinks that he may be looking at a mirage, but as he gradually walks closer, it is revealed that Bruno is actually staring at a young boy. Bruno had read enough books to realize that explorers could never be sure what they were going to find. He believes that there are essentially two categories of discovery. The first category belongs to things that explorers find interesting and are "waiting to be discovered," like the Americas. The second category belongs to things that explorers discover that are better left alone, like dead mice in the back of a cupboard. Bruno immediately puts the boy into the first category because the boy is simply sitting there, waiting to be discovered. Bruno politely introduces himself to the boy, and they have a pleasant conversation.