PrepTest 122, Section 2, Question 23
Commentator: Human behavior cannot be fully understood without(55 more words not shown)
Which one of the following(9 more words not shown)
- ANo support is(17 more words not shown)
- BThe purported evidence(14 more words not shown)
- CIt concludes that(16 more words not shown)
- DIt fails to(14 more words not shown)
- EIt presumes, without(13 more words not shown)
Reading the argument
Calling it “obvious” doesn't give us a reason to believe it.
The commentator says understanding human behavior requires investigating something beyond a person's physical aspects. I'm waiting to hear why. The proposed evidence asks us to imagine knowing every physical event involved in an action, including the brain activity, the body's processes, and the environment. Even then, the commentator says, we still wouldn't understand the action.
But that is the point we were asked to accept in the first place. We need more than a physical account because a complete physical account isn't enough. Changing the wording hasn't supplied an independent reason. Someone who doubted the opening claim would have the same reason to doubt the supposed evidence.
What we’re looking for
For the flaw question, look for an argument that assumes what it is trying to establish. We don't have to prove that a physical account really would explain everything. We just need to notice that the commentator hasn't supported the claim that it wouldn't.
Working the answers
- A
The opening criticism sounds promising, but where is the analogy? The commentator gives a hypothetical case of the very kind of human action under discussion. There is no comparison to some different subject used to support the conclusion. An answer has to describe the whole mistake accurately, not merely begin with words we like.
- BCorrect
The claimed evidence already assumes that a complete physical explanation cannot provide full understanding. That is the central claim the conclusion needs support for. Saying that we would “obviously” still not comprehend the action restates the disputed idea instead of establishing it.
This is what makes the reasoning circular. The problem isn't just that the evidence is weak or that we disagree with it. Accepting this supposed evidence requires us to accept the very point we're asking the commentator to demonstrate.
- C
The argument doesn't say, “Nobody has disproved the need for a nonphysical explanation, so it must be needed.” That would rely on a failure to disprove a claim. Here the author instead presents the disputed claim again as though it were evidence. Those are different mistakes.
- D
An argument needn't list every possible objection or report everything its author knows. Merely failing to state whether contrary evidence exists doesn't identify the defect here. We can locate the problem in the support actually offered: it assumes the conclusion.
- E
“Suppose” introduces a thought experiment. The commentator can ask what would follow if we had a complete physical account without claiming science can actually produce one. The hypothetical also concerns a particular action, whereas E expands to any physical phenomenon. The problem is the unsupported claim about what the imagined account would fail to explain, not the use of a hypothetical.
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