Logical Reasoning Basic Concepts III & IV

Questioning Scope of Arguments

The first basic concept examined in this article deals with the scope of the arguments posed by the LSAT examiners in the logical reasoning (arguments) sections of the LSAT. Perhaps the most important thing to remember when reading an argument posed by an LSAT problem is to never take it as truth. The old saying "don't believe everything you read," could not be more relevant than when you are tackling logical reasoning (arguments) problems on the LSAT. It is important to understand that there are sections of the LSAT where the examinee must take statements made in the LSAT problem as truthful and fully complete for purposes of addressing the problem. Just understand that the logical reasoning (arguments) sections are not such sections.

The way many logical reasoning (arguments) problems attempt to trick the examinee is by stating an argument that has a fairly limited scope. For example, the passage of a logical reasoning (arguments) problem could state:

John prefers two-door cars. That is why John purchased the two-door Ford Mustang.

It should be fairly obvious that the scope of this argument is fairly limited. In other words, there could be many alternative reasons why John bought the Ford Mustang. Perhaps he liked the style, got a good price, liked the powerful engine, etc.

The problem with taking the examiner's posed argument as correct is that it can lead the examinee to improperly narrow his answer choices. Additionally, by properly questioning any asserted arguments, the examinee can often quickly highlight one particular answer choice that stands out as correct. This will be further studied in later articles, but the examinee should be particularly skeptical of instances where the examiner is adamant and demonstrative about a particular argument. This is often an indication that the argument should be questioned.

Mismatched Evidence and Conclusion

This concept is a frequent occurrence in logical reasoning (arguments) problems. The idea is that the examiner provides certain evidence in the passage. That evidence is then used by the examinee to reach a conclusion that is not quite appropriate given the evidence or, more specifically, the degree of evidence provided. The best way to demonstrate this is with an example. Consider the following argument:

Bob did not see the last pitch thrown by Pitcher that struck out the right-handed Slugger. However, because Pitcher almost never throws curve balls to right-handed batters who Pitcher thinks have hitting power; the pitch could not have been a curve ball.

Where to begin! The obvious mismatch of evidence to conclusion occurs with the determination that the pitch could not have been a curve ball (conclusion) when the evidence merely suggests that Pitcher almost never throws curve balls in certain situations. "Almost never" does not lead to "could nots." But wait, there's more. There is another mismatch here because the speaker throws in that Pitcher almost never throws curve balls to right-handed batters he thinks have hitting power. How does the examinee know what Pitcher thinks about Slugger's hitting power? The examinee doesn't and should not make any assumptions in that regard. Again, the key is to not believe what the passage says and read everything very critically.