Only an expert in some branch of psychology could understand why Patrick is behaving irrationally. But no expert is c...

Irina November 7, 2019

@Gozi,

This is a tricky question! Charles is just a random variable, it could say "one", "X" or any other name instead and still be a valid conclusion. Let's look at the argument in the stimulus.

Pr: Only an expert in some branch of psychology could understand why Patrick is behaving irrationally.
The premise tells us that being an expert in a branch of psychology is a necessary condition for understanding Patrick's behavior:

understand -> expert
~expert -> ~ understand

Pr 2: But no expert is certain to be able to solve someone else's problem.

This premise tells us that if someone is able to solve someone else's problem, he is no psychology expert.

solve -> ~ expert
expert -> ~ solve

The basic form of this argument is:
A - > B
B -> ~ C

Notice that A & C are mutually exclusive:
A -> ~C
C -> ~A

meaning we can conclude that if someone can understand Patrick's behavior cannot be certain to solve his problem and vice versa:

understand -> ~ solve
solve -> ~ understand

The correct answer choice (E) can be diagrammed as:

solve -> ~ understand

which is one of our inferences above.

This question is a great example of why you cannot eliminate an answer choice simply because it involves new information. Even though Charles is not mentioned in the stimulus, the name choice has no impact on the conditional logic in the correct answer choice so if the name threw you off, simply replace it with an abstract variable like X and see if the conclusion makes sense.

Gozi November 13, 2019

Great, I got accustomed to taking these problems at "face value" like we were told in the videos early on that I didn't allow for much leeway. I will adjust as you say! Thanks!

hassay18 February 22, 2024

How does "Pr 2: But no expert is certain to be able to solve someone else's problem." conclude that this premise tells us that if someone is able to solve someone else's problem, he is no psychology expert. The premise just means that no expert is - with 100% certainty - able to so solve someone else's problem.

Emil-Kunkin February 22, 2024

The right answer does not actually hinge on C's ability to solve, it's about his confidence in his own ability to solve.