Logical Reasoning Question Types-Inference

Many of the types of problems encountered in the logical reasoning (arguments) sections of the LSAT are denoted by the requirement that the examinee evaluate the statements and conclusion drawn by the problem drafter. Logical reasoning (arguments) inference problems are somewhat different in that these problems don't test the examinee's ability to critique a presented argument so much as they require the examinee to formulate their own conclusion.

There are many different machinations of logical reasoning (arguments) inference problems, but it should be understood from the outset that the overriding goal of the examinee is to logically connect the provided passages. In doing this, the examinee must accept the premises of the statements provided as true. This could lead to some silly results. Consider this basic example as a demonstration of this rudimentary concept:

Lead is heavier than wood.

Uranium is heavier than lead.

The conclusion that can be reached from these statements is that uranium is heavier than wood. It is important to remember that the premises of the given statements must be accepted as true. This means that the examinee should focus on the connection between the provided statements.

The examinee must understand that there are two distinct types of logical reasoning (arguments) inference problems: (1) standard and (2) formal. While standard problems tend to be more approachable and straightforward, most examinees agree that formal problems are the more difficult.

Standard logical reasoning (arguments) inference problems require the examinee to take the information provided in the passage and select the answer that best represents a conclusion that can be inferred from the provided information. The generic format of these questions usually flows as follows:

A is required for B, and B is required for C. Therefore, A is required for C.

A is enough for B, and B is enough for C. Therefore, A is enough for C.

A leads to B, and B leads to C. Therefore, A leads to C.

One popular method for approaching these standard logical reasoning (arguments) inference problems is to utilize the answer elimination method. This entails going through the provided answers and testing each answer. If eliminating the answer choice from the provided argument creates logical problems, that may be the correct answer. Conversely, if the logic of the provided statement is not greatly affected, then that choice is probably incorrect.

Formal logical reasoning (arguments) inference problems utilize a set construction. This often appears in the form of if…then statements, but can also utilize none, all, some, unless and other types of constructions. Again, it is critical for the examinee to understand what can and can't be deduced from the given statement. Consider this relatively simple example:

If Amy is awake, then it is after 10:00 am.

If the examinee is told that Amy is awake, he/she can correctly infer that it is after 10:00 am. If the examinee is told that it is after 10:00 am what can the examinee infer? Absolutely nothing! What if the examinee is told that Amy is not awake? Nothing can be inferred. How about if the examinee is told that it is before 10:00 am? Then the examinee can infer that Amy is not awake. It should be obvious from this simple example why formal logical reasoning (arguments) inference problems create such difficulty for examinees.