Passage Summary: A student claims that if a professor is right about there being no proof for the Egyptian origin of glassblowing, then it must have started somewhere else.

Conclusion: If Professor Vallejo is correct, we must conclude that glassblowing originated somewhere other than Egypt.

Reasoning: If Professor Vallejo is correct, the evidence for the traditional view that glassblowing began in Egypt is insufficient.

Analysis: The student is confusing a lack of evidence with evidence of the contrary. Just because we don't have enough proof to say 'Yes, it was Egypt,' doesn't mean we have proof to say 'No, it wasn't Egypt.' Historians might just be missing the right artifacts. You should look for an answer that identifies this 'absence of evidence' flaw, where the student treats the failure to prove a claim as a definitive debunking of that claim.