Passage Summary: A specific rare stamp gets ruined by light, so it's better to keep it locked in a dark room than to let people see it and destroy it.

Conclusion: Museums should refrain from displaying the rare inverted airplane stamp.

Reasoning: The stamp is highly susceptible to damage from ultraviolet light, and preserving the item is more important than providing public access.

Analysis: This argument moves from a set of facts about physical degradation to a normative 'should' statement. To support this reasoning, we need a principle that bridges the gap between the risk of damage and the decision to hide the object. Look for a rule that prioritizes the long-term preservation of an artifact over the public's immediate desire to view it.