Archaeologists have firm evidence that Norse explorers reached the coast of North America around A.D. 1000, long before Christopher Columbus'...
GMAT Critical Reasoning : (CR) Questions
Archaeologists have firm evidence that Norse explorers reached the coast of North America around A.D. 1000, long before Christopher Columbus' first voyage to America in 1492. Some people claim to have excavated Norse weapons dating from the 1300's in areas far inland from Norse coastal sites. If these claims are true, then the Norse must have explored the interior of North America, as well as the coast, before Columbus' first voyage.
Which of the following is an assumption on which the argument depends?
Passage Analysis:
| Text from Passage | Analysis |
| Archaeologists have firm evidence that Norse explorers reached the coast of North America around A.D. 1000, long before Christopher Columbus' first voyage to America in 1492. |
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| Some people claim to have excavated Norse weapons dating from the 1300's in areas far inland from Norse coastal sites. |
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| If these claims are true, then the Norse must have explored the interior of North America, as well as the coast, before Columbus' first voyage. |
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Argument Flow:
The argument starts with established historical fact (Norse coastal exploration), introduces disputed new evidence (inland weapons), then draws a conditional conclusion about what this evidence would mean if true.
Main Conclusion:
If the claims about inland Norse weapons are true, then the Norse explored the interior of North America before Columbus arrived.
Logical Structure:
The conclusion depends on accepting the weapon claims as legitimate evidence of Norse presence. The argument assumes that finding Norse weapons in an area proves Norse people were actually there exploring, rather than the weapons arriving through other means like trade or migration of objects without explorers.
Prethinking:
Question type:
Assumption - We need to find what the argument takes for granted but doesn't explicitly state. The argument concludes that if Norse weapons from the 1300s are found inland, then Norse explorers must have explored the interior before Columbus.
Precision of Claims
The argument makes a very specific claim about Norse exploration activity - that finding weapons inland proves Norse people explored the interior. This requires precise assumptions about how those weapons got there.
Strategy
To find assumptions, we need to identify ways the conclusion could be false even if the premises are true. The argument jumps from 'Norse weapons found inland' to 'Norse people explored inland.' What could make this logic fail? We need to think about alternative explanations for how Norse weapons could end up inland without Norse people actually exploring there themselves.
This choice suggests we must assume the weapon sites were permanent Norse settlements. However, the argument only concludes that Norse people 'explored' the interior - it doesn't claim they established permanent settlements. Exploration could involve temporary expeditions or brief visits. The argument's conclusion doesn't depend on the permanence of Norse presence, so this isn't a necessary assumption.
This is the correct assumption. The argument jumps from 'Norse weapons found inland' to 'Norse people explored inland.' But what if Native Americans obtained these weapons through trade, warfare, or by finding them at coastal Norse sites, then carried them inland themselves? If this happened, we could find authentic Norse weapons in inland areas without any Norse people ever having explored those regions. The argument absolutely depends on ruling out this alternative explanation, making this assumption essential.
This compares Norse explorers to later explorers in terms of their likelihood to travel inland. However, the argument doesn't make any comparative claims about different groups of explorers. It simply concludes that IF Norse weapons are found inland, THEN Norse people explored inland. The relative exploration patterns of different groups are irrelevant to this specific logical connection.
This suggests Norse explorers wouldn't venture inland without weapons. But this assumption would actually weaken the argument's logic. If Norse people always carried weapons inland, then finding weapons would be expected evidence. The argument works regardless of whether Norse people typically carried weapons or not - the key issue is how the weapons got to where they were found.
This assumes Norse weapon design remained constant between 1000 and 1300 A.D. While this might help with dating accuracy, the argument already accepts that the weapons date from the 1300s. The design consistency doesn't affect the logical leap from 'weapons found inland' to 'Norse people explored inland' - the core reasoning gap the argument depends on addressing.