Passage Summary: An Italian painting contains cobalt. In the 1950s, scientists thought this meant the painting was made after 1804 because that is when cobalt blue pigment was first used in Europe. However, a more recent study found cobalt but concluded the painting might actually be older than 1804.

Reasoning: N/A

Analysis: The paradox lies in how the same chemical element (cobalt) can lead to two opposite dating conclusions. The first group assumed cobalt automatically meant 'cobalt blue pigment,' which has a known start date. To resolve this, we need a reason why cobalt could have been present in a painting before that pigment was invented. Perhaps there is another, older pigment that contains cobalt, or maybe cobalt was used in a different capacity in Italian art. Look for an answer that provides an alternative source for cobalt available before 1804.