```
public traverse(node)
  if (node == null)
    return
  traverse(node.left)
  visit(node)
  traverse(node.right)

public visit(node)
  //Look at node

public absurd()
  return 1/0

public main()
  traverse(node)
  try(absurd())
  catch(impossible)

```

This pseudocode represents a famous quote, what is that quote?