Logical reasoning PrepTest 158 · Section 4 · Question 8

This doesn't express the same idea as our anticipated main point. This omits the climatologist's belief that the scientists' conclusion near these warming waters is "far from justified." While this answer choice is true, it doesn't capture the climatologist's main point.

This is tempting, but it's stated with more bold language than the climatologist's conclusion. The climatologist concludes that the scientists' conclusion is "far from justified." That means the climatologist thinks the scientists didn't provide enough evidence to prove that the 4-degree increase in water temp is a symptom of global warming. So, we can only conclude that the climatologist believes that the 4-degree increase might not be a symptom of global warming. We can't say that the climatologist believes that the 4-degree increase is definitely not a symptom of global warming. Arguing that a conclusion isn't justified isn't the same as arguing that a conclusion is false.

Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Main Point

Passage Summary:
Pacific coast waters warmed by 4 degrees over the last 15 years. Some scientists say global warming caused the increase. However, that conclusion isn't justified. Ocean temperatures can change naturally over 60 years.

Strategy Overview:

1. Identify the conclusion
2. Identify the premises
3. Make sure the premises support the identified conclusion, and that the identified conclusion does not support anything else in the passage
4. Find the answer choice that restates the conclusion

Answer Anticipation:
Our job is straightforward on Main Point questions: find the main conclusion the author wants to convey. When searching for main conclusions, it helps to look for words associated with conclusions — like "therefore," "hence," and "thus" — or "shift" words — like "however," "but," and "nevertheless." Authors often use these words to introduce conclusions.

In this case, the "shift" word "However" appears in the last sentence. That suggests that the claim that "this conclusion is far from justified" is the climatologist's main conclusion. That sentence also expresses a vague, negative statement. Statements like these — statements that express some sort of disagreement with another argument — are often the conclusion on Main Point questions.

Of course, the statement “this conclusion is far from justified" doesn’t mean anything on its own. It’s too vague. So, we'll need to fill in the details by referring to the other argument. The other argument concludes that the 4-degree increase in Pacific waters is a “symptom of a more general, global warming caused by human-generated air pollution.” If the climatologist doesn’t believe that conclusion is justified, they must believe the 4-degree increase might not be a symptom of global warming. So, that’s how we'll articulate this argument’s conclusion.

To confirm that this sentence is the conclusion, we need to identify the premises of this argument and verify that they all support that last sentence. So, why does this climatologist believe the 4-degree increase might not be a symptom of global warming? The second half of the last sentence gives us a reason — ocean temperatures can change naturally over 60 years. If temperatures can change naturally, then the temperature increase might not be caused by humans.

So, the claim that the 4-degree increase in Pacific water temperatures might not be a symptom of global warming has support, which makes it a conclusion. And because that claim doesn't support any other statement in this passage, we know it's the main conclusion. Now, we just need to look for an answer choice that expresses the same idea as that main conclusion. 

Answer Choice Explanation:
This is almost precisely what we anticipated. It captures the climatologist's belief that the scientists' conclusion — that the 4-degree increase in Pacific water temp is a symptom of global warming — is "far from justified." The climatologist supports this belief by referencing an alternative explanation — natural cycles that can change ocean temperatures. This answer choice captures the main idea the climatologist wants to convince us of, so we can select (C) and move on to the next question.

Key Takeaway:
When searching for main conclusions on Main Point questions, it helps to look for "shift" words — like "however," "but," and "nevertheless." Authors often use these words to introduce conclusions. Statements expressing disagreement with another argument are also often the conclusion on Main Point questions.

This is tempting, but it reflects a premise the climatologist relies on, not the climatologist's main conclusion. The climatologist concludes that the scientists' conclusion is "far from justified." That means the climatologist thinks the scientists didn't provide enough evidence to prove that the 4-degree increase in water temp is a symptom of global warming. The climatologist supports this conclusion by referencing an alternative explanation — natural cycles that can change ocean temperatures. So, the climatologist uses the premise that the increased water temps may be caused by a natural cycle of ocean temperature changes to support the conclusion that the scientists' conclusion isn't justified.

This does not express a claim the climatologist necessarily believes. This claim implies that the warmer Pacific temps cannot caused by natural cycles and global warming. The climatologist never says or implies that. The climatologist only says that the scientists' conclusion that the warmer temps are caused by global warming isn't justified. The climatologist supports this conclusion by referencing an alternative explanation — natural cycles that can change ocean temperatures. Even though the climatologist references an alternative explanation, that doesn't mean the climatologist thinks the two explanations are mutually exclusive. The climatologist could argue that, in some cases, a temperature increase could be caused by natural cycles but compounded by global warming.