Logical reasoning PrepTest 105 · Section 2 · Question 12

Flawed

Cause & Effect / Weaken Questions

Some infants fed just breast milk get colic, so it’s probably not the case that colic is caused by antibodies in cow’s milk.

Weaken questions frequently deal with causality, and when they do, we have standard answers we can look for to weaken the argument. This one does deal with causality, but it’s not the standard Correlation/Causation flaw - rather, it argues that one thing doesn’t cause another. Here, the conclusion states that colic isn’t caused by antibodies in cow’s milk. How does it go about proving it? It actually uses a common method that we’d use to weaken a causal argument - it brings up counterexamples! The argument discusses infants who are fed exclusively breast milk and still develop colic, suggesting that this means the colic can’t be caused by antibodies from cow’s milk. When this happens, we should check to see if the supposed counterexamples are actually counterexamples to the claim being countered. Here, if the babies are not being exposed to antibodies in cow’s milk and still get colic, then they do serve as counterexamples. However, the argument doesn’t establish that they aren’t being exposed to antibodies from cow’s milk. It just shows that they’re not drinking cow’s milk. They could be exposed through some other means - for instance, maybe the breast milk contains the antibodies if the mom consumes dairy products. Anything that suggests the babies offered as a counterexample are, in fact, being exposed to these antibodies would weaken the argument that these antibodies aren’t the cause of colic, so let’s find an answer that provides evidence of it.