Passage Summary: Since we discovered the colors of these famous paintings are different than we thought, our old ideas about what the paintings mean might be wrong.

Conclusion: Interpretations of the Sistine Chapel frescoes made before their cleaning may no longer be valid.

Reasoning: The restoration process revealed that the actual colors of the frescoes are different from what art historians previously believed them to be.

Analysis: The historians are assuming a direct link between the physical appearance of a work (its color) and its meaning (its interpretation). To justify this reasoning, we need a principle that makes this link explicit. Look for a rule that states that an interpretation of an artwork is dependent upon its original physical characteristics. If the color is a fundamental part of the 'message,' then changing our understanding of the color must necessitate changing our understanding of the message.