Political scientist:  All governments worthy of respect allow their citizens to dissent from governmental policies. N...

Naz September 26, 2014

Let's diagram this:

"All governments worthy of respect allow their citizens to dissent from governmental policies."

P1: GWR ==> ACDGP
not ACDGP ==> not GWR

"No government worthy of respect leaves minorities unprotected."

P2: GWR ==> not LMUP
LMUP ==> not GWR

"Thus, any government that protects minorities permits criticism of its policies."

C: not LMUP ==> ACDGP
not ACDGP ==> LMUP

So the argument takes the necessary condition of P2, "not LMUP," and uses it to infer the sufficient condition of P2, "GWR." From there it invokes P1 to conclude that because we have "GWR," we must then have "ACDGP."

However, as you know, we cannot infer anything from a necessary condition. So, we cannot conclude "GWR" from "not LMUP."

Answer choice (B) has this same flaw.

"All jazz musicians are capable of improvising."

P1: JM ==> CI
not CI ==> not JM

"No jazz musician is incapable of reading music."

P2: JM ==> CRM
not CRM ==> not JM

"Therefore, all musicians who can read music can improvise.

C: CRM ==> CI
not CI ==> not CRM

Just as in the stimulus, answer choice (B) takes the necessary condition of P2, "CRM," to infer the sufficient condition of P2, "JM." From there it invokes P1 to conclude that because "JM" is present, we must have "CI."

So, again, we see the flaw of using the necessary condition to infer a sufficient condition. But, we know that we cannot infer anything from the presence of a necessary condition.

Thus, answer choice (B) has the exact flawed reasoning as the stimulus.

Hope that clears things up! Please let us know if you have any other questions.

rexcoleman September 26, 2017

Hi Naz. Will you diagram out answer choice C please? This seems to follow similar flawed reasoning: don't infer anything from the necessary condition. The only difference I see is that answer choice C uses the necessary condition from P1 and not P2.

irinacionca October 18, 2017

I'm with Rex. I also chose C

jordangendron December 1, 2017

I am not understanding how to diagram answer choice A. I know it's not the correct answer, but I'm trying to work through the whole problem. Will you please diagram it?

sweingar April 21, 2018

@naz can we have a diagram for answer choice C please?

Alex June 1, 2018

@naz @mehren yes C please?

Mehran June 2, 2018

Hi @sweingar, @Alex & others, thanks for your posts.

"All governments worthy of respect allow their citizens to dissent from governmental policies."

P1: GWR ==> ACDGP
not ACDGP ==> not GWR

"No government worthy of respect leaves minorities unprotected."

P2: GWR ==> not LMUP
LMUP ==> not GWR

"Thus, any government that protects minorities permits criticism of its policies."

C: not LMUP ==> ACDGP
not ACDGP ==> LMUP

So the argument takes the necessary condition of P2, "not LMUP," and uses it to infer the sufficient condition of P2, "GWR." From there, it invokes P1 to conclude that because we have "GWR," we must then have "ACDGP."

However, as you know, we cannot infer anything from a necessary condition. So, we cannot conclude "GWR" from "not LMUP."

Answer choice (C) can be diagrammed as follows:

"Ecosystems with cool, dry climates are populated by large mammals."
P1: CDC ==> PLM
not PLM ==> not CDC

"No ecosystems populated by large mammals have abundant and varied plant life."

P2: PLM ==> not AVPL
AVPL ==> not PLM

"Thus, ecosystems that do not have cool, dry climates have abundant and varied plant life."
C: not CDC ==> AVPL

If you combine the contrapositive of P2 and the contrapositive of P1, you get:
AVPL ==> not PLM ==> not CDC

Which in shorthand is:
AVPL ==> not CDC

The conclusion is an incorrect reversal of this transitive point. Different flaw from the stimulus and correct answer, as explained earlier in this thread.

Hope this helps! Please let us know if you have any additional questions.

Christy-Earls July 6, 2018

Could you please provide an example of how you would diagram choice A?? I know it's not the right answer, but I blew through all my time for this question trying to figure that out. Thanks!

Randi October 28, 2020

Why is it that the conclusion's sufficient condition is "not LMUP" when the sentence states that the government protects minorities instead of not protecting minorities?

Thus, any government that protects minorities permits criticism of its policies."

C: not LMUP ==> ACDGP
not ACDGP ==> LMUP

Victoria November 13, 2020

Hi there,

It's a bit confusing with the double negative, but the sufficient condition is saying that the government does not leave minorities unprotected; therefore, the government protects minorities.

Hope this helps! Please let us know if you have any further questions.