Passage Summary: The author claims that because some people survive brain damage just fine, most of our brain is useless right now, but if we learn to use it, we'll become geniuses who can solve anything.

Conclusion: Tapping into the currently unused portions of the human brain will enable us to solve problems that are presently considered impossible.

Reasoning: The fact that people with significant brain damage often show no negative effects suggests that over 90 percent of the brain currently serves no purpose.

Analysis: The argument suffers from a classic 'gap' in logic by assuming that a lack of 'discernible adverse effects' from damage means those brain regions have no function at all. It further leaps to the conclusion that these supposedly 'purposeless' areas are actually reservoirs of 'creativity and innovation' just waiting to be switched on. You should look for an answer choice that identifies this unwarranted assumption that 'no obvious damage' equals 'no current function' or 'future potential.' It's a bit like assuming that because your car still runs after you remove the radio, the radio was actually a hidden turbocharger.