The first skill I teach new students is to “find the conclusion.” This is essential but not easy. Until they develop an intuitive sense of what a conclusion is and how it relates to the argument as a whole, students need external cues to help them find the conclusion. One of those cues is what I call the “should” principle.
The “Should” Principle: if the word “should” appears in a stimulus, it will probably appear in the conclusion.
This is a “principle,” not a “rule, because it is not always and necessarily reliable. I haven’t gone through every PrepTest yet. I’m eager to find some counterexamples so that I can refine the principle a little. As of now, however, I have not found a single stimulus with the word “should” in it that doesn’t have “should” in the conclusion. (If you can find a counterexample, please identify it in the comments!)
There are two different reasons for this principle. The word “should” appears in moral arguments but not in factual arguments. One would expect the word “should” throughout a moral argument, especially in the conclusion.
We should obey the law.
The law says we should not drive faster than the speed limit.
THEREFORE, we should not drive faster than the speed limit.
Explicitly moral arguments are relatively rare, however. Arguments about facts are much more common. In real life and on the LSAT, however, a argument about the facts usually has a higher purpose. People may debate whether it will rain this afternoon, but not because they’re abstractly interested in the weather. What they really want to know is whether to cancel the picnic.
Kaplan’s LSAT Premier Chapter 9 lists six types of conclusions: value judgments, if/then conditionals, predictions, comparisons, assertions, and recommendations. When an argument about facts leads to a prediction, judgment, or recommendation, it may easily result in “should.”
The word “should” appears in six stimuli in the June 2007 PrepTest (the only test that is publicly accessible). All instances obey the “should” principle.
- Section II, Question 10: “should” appears twice in this moral argument.
- Section II, Question 16: “should” in the conclusion of “Sandra’s” short argument.
- Section II, Question 17: “should” is the recommendation after a factual argument.
- Section II, Question 20: “One should not assume” is the conclusion.
- Section III, Question 14: “should” only appears once in this moral argument, in the conclusion.
- Section III, Question 20: “should” is a recommendation.
A word of caution is in order–the “should” principle is a fast way to find the conclusion, but it is not a reliable indicator of the right answer. The LSAT is full of synonyms for “should.” For example, Section II, Question 10 is a “Main Point” question where the conclusion in the stimulus is “Double-blind techniques should be used whenever possible in scientific experiments.” The correct answer is, “It is advisable for scientists to use double-blind techniques in as high a proportion of their experiments as they can.”
Summing this up in LSAT terminology, “should” is a sufficient condition for a conclusion, but not a necessary condition.
That still doesn’t mean that every sentence with a “should” in it is a conclusion–the principle is narrower and more specific. If the word “should” only appears once in a stimulus, then it is in the conclusion. If “should” appears twice (or more) in a stimulus, then it will be in the conclusion as well as in a premise.