Let's try the Zen/taoist analogy. At the end of the day, a Zen master tells his student: "your next lesson will start at 5am tomorrow, don't be late"; the stud

Let's try the Zen/taoist analogy. At the end of the day, a Zen master tells his student: "your next lesson will start at 5am tomorrow, don't be late"; the student says: "what will happen if I am late?". The master doesn't reply. The student goes to sleep and wakes up late. "You missed your lesson, come back tomorrow at 4am or else I can't guarantee your safety.". The next day, the student arrives on time. ---- Saying things are undefined is an explicit way of demarcating what is part or not of the specification. Otherwise, the meaning could ambiguous.