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#10 - The consequences of surgical errors can be devastating

LSAT Leader
Posts: 25
Joined: Tue Jul 04, 2017 1:48 pm
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Question 10. "The consequences of surgical errors can be devastating..."

The correct answer for this problem is answer choice B.

Could you explain why this is right? I was stuck between A and B but ended up eliminating B because the stimulus referred to "highly competent" and "extremely competent" whereas this answer choice did not. If, for example, plastic surgeons were competent but not "highly" or "extremely" competent, would the fact that they were just cpmpetent be enough to weaken this argument?

Thank you.
James Finch
PowerScore Staff
PowerScore Staff
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Joined: Wed Sep 06, 2017 5:06 pm
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Hi Olaf,

The difference between answer choices (A) and (B) comes down to what the stimulus tells us we already know versus what we don't. This is a conditional reasoning problem, so I'll start with the conditional statements given:

"No one would want to risk surgery unless it was performed by someone highly competent to perform surgery."

Unless is a signifier for a necessary condition here so the statement should be diagrammed as:

risk surgery :arrow: performer is highly competent

and the contrapositive:

performer is highly competent :arrow: risk surgery

Then we are given that general surgeons are "extremely competent to perform surgery" which we can diagram as:

general surgeon :arrow: highly competent


highly competent :arrow: general surgeon

Lastly, the stimulus concludes by saying that having surgery performed by anoyone but a general surgeon "involves highly undesirable risks," which diagrams out as:

general surgeon :arrow: risk surgery

So what's wrong with the conclusion? It relies upon a mistaken negation of the second conditional statement to draw a false inference that only general surgeons are competent enough to risk having perform surgery.

Answer choice (A) is false, because the second conditional statement tells us that all general surgeon are competent, and thus there cannot be any general surgeons who are incompetent.

Answer choice (B) correctly identifies the issue that we only know that all general surgeons are competent enough to risk performing surgery, but we don't know anything about other doctors. Maybe some others are competent enough to perform surgery, or maybe not, but we cannot exclude the possibility.

Hope this clears things up!
LSAT Leader
Posts: 25
Joined: Tue Jul 04, 2017 1:48 pm
Points: 26

It makes sense now, thanks!