Passage Summary: Anne thinks a comet flare is rare because we haven't seen one before, but Sue argues we only saw this one because we were actually looking, implying they might happen all the time.

Conclusion: Sue challenges Anne's conclusion that the comet's flare was a highly unusual event.

Reasoning: Sue points out that the lack of previous observations is likely due to a lack of effort in looking, rather than the rarity of the event itself.

Analysis: Sue is attacking the evidence Anne uses to support her 'unusual' claim. Anne assumes that 'never observed' means 'never happened,' but Sue provides an alternative explanation for why it was never observed: no one was watching. This is a classic 'absence of evidence is not evidence of absence' rebuttal. Focus on how Sue undermines the representative nature of Anne's data by suggesting the sample was biased toward times when we weren't looking.