Now imagine this in a work setting. You are given a piece of software you know nothing about and you are supposed to test it. You have no idea of the process it went through up until that point. What is its primary objective? Does it take into consideration edge cases? Has it been tested before? What is the best way for you test it?
This is a question which is very common among good testers. That is the whole point of blackbox testing. Here is an example: http://www.workroom-productions.com/olderBlackBox.html There is also an extreme version of this where the question is can you test something which is in a glass case. The answer is yes. You can find that on satisfice.com