#15 - Ordinary mountain sickness, a common condition

[Adam Tyson]

Because it is not necessary for the argument to be valid, Hazel03. To prove that, let's try the Negation Technique. What if ordinary mountain sickness DOES involve disruption of blood circulation in the brain? What does that do to the claim that cerebral edema is especially dangerous at high altitudes?

Looking to my answer earlier in this thread, does this similarity between the symptomsof the two sicknesses tell us anything about the treatment of those two sicknesses? While it might seem reasonable to think that similar symptoms require similar treatment, it's not necessarily true. It's still possible that cerebral edema is especially dangerous at high altitudes, where it might be confused for mountain sickness and be incorrectly treated. Answer C, when negated, does nothing to harm that conclusion, and so it is not a required assumption of the argument.

The author here MUST believe that the treatments differ. If they do not, then there is no reason to believe that cerebral edema is particularly dangerous at high altitudes. A misdiagnosis would be irrelevant if that were the case. The argument is destroyed by the negation of answer A, proving A must be a required assumption.