Logical Reasoning Basic Concept II

The logical reasoning (arguments) sections of the LSAT tend to place a heavy emphasis on causation. Causation can appear in many forms in logical reasoning (arguments) problems. The most useful skill that any examinee should focus on is determining the relative strength or weakness established by a statement of causation regardless of the specific type of question that the causal statement appears within.

The strength or weakness of a causal relationship can run the full spectrum from very strong (or highly probable) to very weak (not probable). As with most areas of the LSAT, practice in this area is the best way to gain familiarity. An example may clear up any ambiguity in this context. Consider the following causal statement:

Because grandma lived in a house with asbestos for 50 years, she died of lung problems at a young age.

This statement sets up the causal relationship that the grandmother died of lung disease because of asbestos. While there could be other reasons that she developed lung disease (e.g. she smoked, was genetically predisposed, etc.) the fact that she lived in a house that exposed her to asbestos creates a pretty safe assumption as to the cause of her lung disease. Therefore, this causal statement is fairly strong. Now consider this statement:

Grandma never liked eating vegetables; this caused her to die before she reached normal life expectancy.

It should be obvious that this causal statement is far weaker than the previous causal statement. In the latter statement, all that we are told is that grandma didn't like eating vegetables and that she died prior to attaining normal life expectancy. First of all, we're not sure that just because grandma didn't like eating vegetables that she didn't in fact eat them anyway. Additionally, grandma could have been subject to other circumstances. For example, she could have been a smoker; strokes or heart attacks could run in her family, etc.

The determination of the strength or weakness of a causal statement is established by considering other potential causes of the final result in addition to the cause offered by the LSAT writer. If it is easy to think of many other causes, then the causal relationship is weak, and vice versa. It is also important that the examinee be aware of compound causal statements. For example, a logical reasoning (arguments) problem could have several causation statements, but only one is really relevant to the question asked. Often the relevant causation statement will be stronger or weaker than the other causation statements in the passage. This highlights the benefits of carefully reading the question stem prior to reading the passage as it will help the examinee focus on and identify the relevant causation statement in the passage. The examinee should always consider two things when a passage establishes a causal relationship between two or more items: (1) simply because one event precedes another doesn't mean that it caused the latter event; and (2) simply because two things are in some way related doesn't mean that one causes the other.