Explore this topic further by using one of the tasks / questions below.
Application to your work
Do you always know your purpose, when you test? How do you know? Where does it come from?
Where does your judgement come from? What might influence you to change your mind about something you've already judged?
What role do requirements play, in developing your judgement? What counts as a "requirement"? User stories? Acceptance criteria? Cultural expectations?
Have you ever judged that something was a problem, then decided that it wasn't? What made you change your mind? In what circumstances might you change your mind just by exploring the system further?
Can you test without requirements? What can you test?
Can you explore without requirements? What can you explore?
Further Reading
Alan Richardson's Dear Evil Tester book, particularly "What is Exploratory Testing?"
James Lyndsay, Workroom Productions
@workroomprds, +447904158752