I was mostly relieved. I wasn't insane after all. Some problems are simple, some hard, and some can't be solved. These approaches are very indirect and people m

I was mostly relieved. I wasn't insane after all. Some problems are simple, some hard, and some can't be solved. These approaches are very indirect and people may be tempted to use them without first asking the question: can this problem be solved (in principle!) with the data that we have?