Question

Bevex, an artificial sweetener used only in soft drinks, is carcinogenic for mice, but only when it is consumed in very large quantities. To ingest an amount of Bevex equivalent to the amount fed to the mice in the relevant studies, a person would have to drink 25 cans of Bevex-sweetened soft drinks per day. For that reason, Bevex is in fact safe for people. In order for the conclusion that Bevex is safe for people to be properly drawn, which one of the following must be true? (A) Cancer from carcinogenic substances develops more slowly in mice than it does in people. (B) If all food additives that are currently used in foods were tested, some would be found to be carcinogenic for mice. (C) People drink fewer than 25 cans of Bevexsweetened soda per day. (D) People can obtain important health benefits by controlling their weight through the use of artificially sweetened soft drinks. (E) Some of the studies done on Bevex were not relevant to the question of whether or not Bevex is carcinogenic for people.

Short answer

Option (C) is necessary to ensure Bevex is safe for humans.

Step-by-step solution

Understanding the Argument

The argument states that Bevex is carcinogenic to mice only in large quantities. To match the mice's exposure, a human would need to consume 25 cans of Bevex-sweetened drink daily. Hence, it's safe for humans.

Identifying the Assumption

The conclusion that Bevex is safe for people relies on the assumption that humans will not consume it in quantities that are carcinogenic to mice. This means that humans consume fewer than 25 cans daily.

Evaluating the Answer Choices

Check which option ensures Bevex is safe by preventing the conditions under which it is harmful in mice. Analyze each option to see which aligns with the assumption.

Analyzing Each Option

Option (C) indicates that people drink fewer than 25 cans daily, directly supporting the crucial assumption needed for the conclusion. Other options do not address consumer behavior or exposure differences between mice and humans concerning the 25-can threshold.

Concluding the Correct Choice

Option (C) is necessary to affirm the argument's conclusion because it ensures humans won't consume Bevex in the harmful quantities observed in mice studies.

Key concepts

Logical Reasoning Practice

Sharpening logical reasoning abilities is essential for tackling complex arguments. In the scenario where Bevex, a sweetener, is considered safe for humans because it is carcinogenic only in large quantities for mice, logical reasoning helps us understand the underlying structure.
Logical reasoning involves:

• Identifying the premises, which here include the known effects of Bevex on mice.
• Understanding the conclusion, which is the claim about human safety.
• Evaluating the logical flow from premises to conclusion.

For any logical reasoning exercise, it's crucial to ensure that the conclusion follows inevitably from the premises.
Practice by consistently looking for gaps or unwritten assumptions that must be true for the argument to hold.

Critical Thinking Skills

Critical thinking is a core skill in dissecting arguments like the one about Bevex. It allows us to assess each element of the argument.
Engaging in critical thinking involves:

• Questioning the validity of the premises. For instance, are the studies on mice truly reflective of potential risks to humans?
• Reflecting on assumptions. Are there underlying assumptions that the argument takes for granted?
• Considering alternative perspectives. Could there be other explanations or additional data that might affect the conclusion?

By honing critical thinking skills, students can navigate through complex arguments and evaluate their worth accurately. Each claim should be examined based on evidence, logic, and potential gaps.

Assumption Identification

Assumption identification is a pivotal skill in logical reasoning tasks. In our Bevex scenario, the conclusion—that it is safe for humans—relies heavily on an implicit assumption.
An assumption is a statement presumed true for the argument, but not outright stated. Here, the assumption is that people do not commonly drink 25 or more cans of Bevex daily. This assumption fills a critical gap between the evidence and the conclusion.
Key steps in assumption identification include:

• Identifying any gaps between premises and conclusions.
• Determining what must be true for the argument to remain valid.
• Verifying whether the identified assumption is truly necessary for the argument.

Spotting assumptions helps clarify the argument’s foundation and reveals its potential weaknesses.

Argument Analysis

Analyzing arguments requires a thoughtful examination of how various parts of an argument come together. In the Bevex argument, for example, analyzing involves evaluating how evidence about mice is applied to humans.

• Examine comparative analysis: Evaluate whether comparisons, such as between mice and humans, are justified and sound.
• Scrutinize evidence strength: Consider the robustness and relevance of the scientific studies cited.
• Connect evidence to conclusion: Assess whether the provided evidence sufficiently supports the stated conclusion.

Argument analysis requires us to think critically about each claim’s legitimacy and how well the parts of the argument align. Through this process, we can determine the argument's strength and whether its conclusion is reasonably supported.