Passage Summary: Some people think ancient stone-builders were smart because their stones line up with the sun. Dobson says that since there are so many stones, a few were bound to line up by accident, so the builders definitely didn't know anything about the stars.

Conclusion: The ancient people who constructed the stone ring lacked knowledge of astronomical events.

Reasoning: Because there are so many stones in the ring, the fact that two of them align with the spring equinox sunrise is likely a statistical coincidence rather than intentional.

Analysis: Dobson commits a classic 'absence of evidence' flaw. He points out that the evidence for the builders' knowledge (the stone alignment) might just be a coincidence, which is a fair critique. However, he then oversteps by concluding that the builders definitely *weren't* knowledgeable. Just because one piece of evidence is shaky doesn't mean the opposite of the conclusion is true. Look for an answer that describes this leap from 'the evidence is weak' to 'the claim is false.'