How I Overcame GMAT Critical Reasoning Questions - Reasoning from first premises

This was a simple technique I figured out while preparing for the GMAT, to help me break down logical problems in the critical reasoning section. I have found it to be really helpful ever since, such as when trying to reason through problems and statements being made in various situations. This helped me reach scores in the 90th percentile for verbal questions, so I hope it can help you too.

When trying to reason through a scenario, it is vital to first Identify the underlying premises of the statement. To take a classic example of logical reasoning:

Identify the premise(s), and validate the conclusion. That’s the gist! I’m surprised by how helpful this has been, especially when I’m presented with an argument that feels wrong but am finding it hard to pin down exactly why. Once I’m able to identify the underlying premises of the argument being made, I find it much easier to accept or dismiss the position with greater clarity.

Some tips on how to apply this in practice:
1. Writing this out makes it far easier to figure out the logical answer that follows from the question or proposition.
2. If you can’t identify the premise(s) easily, start with the conclusion, to better reason your way to the premise(s).

Let’s try applying this to a 700-level critical reasoning GMAT sample question here, from the GMAT club. Try reasoning it out yourself first using the process I’ve outlined above, before reading the “Application” section below!

Question

We have a moral obligation not to destroy books, even if they belong to us. The reason is quite simple: If preserved, books will almost certainly contribute to the intellectual and emotional enrichment of future generations.

Which one of the following most accurately expresses the principle underlying the argument?

A. It is morally incumbent upon us to devote effort to performing actions that have at least some chance of improving other people’s lives.

B. We are morally obligated to preserve anything that past generations had preserved for our intellectual and emotional enrichment.

C. The moral commitments we have to future generations supersede the moral commitments we have to the present generation.

D. We are morally obligated not to destroy anything that will most likely enrich, either intellectually or emotionally, our posterity.

E. Being morally obligated not to destroy something requires that we be reasonably assured that that thing will lead to the betterment of someone we know.

Application

Applying the process, let’s identify the premises of the argument here. Without looking at the answers, we can see that:

On this basis, the statement that best concurs with the above premise and conclusion, without adding, removing or modifying any propositions, is statement D.

When evaluating the merits of an argument and whether it can stand on the basis of its claims, it is important to reason with just the information being presented in the argument, and not to add on inferences from our own experiences or “common sense”.

That is probably the trickiest part of applying this technique, to be able to catch ourselves when we are accidentally adding on our own assumptions, and realising that it’s not actually what the statement is claiming at all.

Happy reasoning!