October 2010 LSAT Section 1 Question 9

In the first paragraph, the author refers to a highly reputed critic's persistence in believing van Meegeren's forger...

Saksham-Sabarwal on January 7, 2021

Example 4

Shouldn't the last line be "it will lift restriction on steel import" rather than "it will not lift restriction on steel import" because if no restriction is lifted then it will conclude that it will allow steel import, which according to me should not be the case.

Replies

Create a free account to read and take part in forum discussions.

Already have an account? log in

Saksham-Sabarwal on March 23, 2021

anyone?

Laura_21 on January 23, 2022

The diagram on example 4 makes perfect sense through the first 2 lines:
MSI --> HDSM
HDSM --> not G do it

Then in the video explanation, Mehran pulls out another premise of HDSM as his third line of logic:
MSI --> HDSM
HDSM --> not G do it
*HDSM*

This third line of logic is where I am lost.

My questions are:
-Where did this third line come from in the prompt?
- Do we really need this third line? Can't we already assume that from line 2?
-If we use the transitive property from to come up with MSI--> notG do it, I end up with an incorrect negation. Is it incorrect to apply the transitive property here? Or what have I missed?

Thank you so much for your help!

Abigail on January 23, 2022

Hello @laura_21,

Great questions! I'll tackle them in order.

The third line came from the second sentence in the premise: "Since the present government will not do anything that would harm the domestic steel industry." Which could also have been written as either one or two premises. The third premise comes from the fact that you can assume that the present government is currently in office. So, it would be *HDSM*. Alternatively, you could write is as "present government --> *HDSM*.
No, you don't really need the third line. An alternative way to diagram it could be:

Premise 1: MSI --> HDSM
Premise 2: *HDSM*
Conclusion: *MSI*

Here, the conclusion follows from taking the contra positive of the first premise and satisfying its sufficient condition (*HDSM*) with the second premise.

For your third question, you can technically apply the transitive property there, but that was not the way that Mehran was referring to in the video. You have to assume that the current government in currently in office so whatever it doesn't do is not going to happen. If you take the contra positive of the statement that you got (MSI --> notG do it) then you get G do it-->*MSI*. In other words, just "*MSI*" since the current government is in office and its going to do whatever it is going to do. The transitive property that Mehran was referring to was by taking the contrapositive of the two premises G do it --> *HDSM* combined with *HDSM*-->*MSI* which gives us *MSI* .

I hope that clears everything up. Feel free to follow-up.

Abigail