Logical reasoning PrepTest 117 · Section 2 · Question 15

Incorrect. This answer doesn't connect that process to earthquakes or Sweden, so this answer doesn't support the conclusion.

Incorrect. First, this answer doesn't guarantee that Sweden is one of those areas. Second, it doesn't establish that these cracks are the result of the melting of ice, which is the noted cause in the conclusion. Third, this answer doesn't connect any of this to causing earthquakes. This answer can be tempting, but there are too many jumps to make it work.

Incorrect. This answer provides a correlation between the end of the Ice Age and earthquakes elsewhere. That might strengthen the argument that something at the end of the Ice Age caused earthquakes, though even then we'd need to know that the earthquakes in Sweden and Canada were higher than average. It doesn't strengthen the argument that this was the melting of ice.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen

Stimulus Summary:
At the end of the Ice Age:
(1) Ice melting reduced pressure on the Earth, resulting in cracks in the crust
(2) There were a lot of earthquakes in Sweden
Therefore — Ice melting was likely a causal factor in these earthquakes

Answer Anticipation:
This argument is interesting in what it teaches us about some key issues around causality on the LSAT.

Generally, a Strengthen question that features a causal conclusion is committing a correlation/causation flaw. Here, the conclusion is causal—it states that melting ice likely contributed to" the Swedish earthquakes.

The premises, however, are a mix of causality and correlations. Ice melting did cause ("reduced")pressure to be reduced on the Earth's crust, and that pressure being reduced did cause ("As a result") cracks in the Earth's crust. However, the earthquakes seen in Sweden were correlated with the ice melting and the resulting effects.

So what do we make of this? Do the causal premises allow a causal conclusion to be drawn, and we need to look elsewhere for the flaw? Or is the correlation making this an argument with a correlation/causation flaw?

The answer to that is a little more complex than just yes/no. The issue here is that the causal chain allows us to conclude that the ice melting contributed to the formation of cracks, and that coincided with severe earthquakes in Sweden. However, we don't know if cracks in the earth's crust cause earthquakes, or that Sweden was a location where this happened!

So there are really two issues here. First, there's a shift between the end of the causal chain—cracks forming—and the effect in the conclusion—earthquakes. Second, there's an assumption that Sweden, where the earthquakes happened, also had melting ice contributing to cracks. Both are a bit of a term shift/missing link, and both are also a bit of a correlation/causation jump. Whatever the case, we should look for an answer establishing these connections. Either one will do!

Answer Explanation:
This answer connects the causal chain in the premises to the causal relationship in the conclusion. The premises establish that the melting ice from the Ice Age resulted in cracks, and this takes that a step further and connects it to earthquakes. While it doesn't establish that this process was present in Sweden and thus a potential cause of those earthquakes, it does establish that they're a potential cause of earthquakes, which is a necessary part of reaching the conclusion. This answer is therefore correct.

Key Takeaway:
Causality can chain together much as conditionals can, and arguments can similarly have gaps in causal chains.

Incorrect. This answer provides an alternative cause of the earthquakes, thus weakening the argument.