Asking the Right Questions, A Guide to Critical Thinking, 8th Ed

168 Chapter 12
By asking questions learned in previous chapters, such as those concerning
ambiguity, assumptions, and evidence, you will detect much important missing information.
This chapter tries to sensitize you even more to the importance of what
is not said and to serve as an important reminder that we react to an incomplete
picture of an argument when we evaluate only the explicit parts. We thus devote
this chapter to an extremely important additional question you must ask to judge
the quality of reasoning: What significant information is omitted?
(J)
Critical Question: What significant information is omitted?
The Benefits of Detecting Omitted Information
You should remember that almost any information that you encounter has a
purpose. In other words, its organization was selected and organized by someone
who hoped that it would affect your thinking in some way. Hence, your
task is to decide whether you wish to be an instrument of the chosen purpose.
Often that purpose is to persuade you.
Advertisers, teachers, politicians, authors, speakers, and parents all organize
information to shape your decisions. It is a natural and highly predictable
desire on their part. Thus, those trying to persuade you will almost always try
to present their position in the strongest possible light. So when you find what
you believe to be persuasive reasons—those gold nuggets for which you are
prospecting—it's wise to hesitate and to think about what the author may not
have told you, something that your critical questioning has not yet revealed.
By significant omitted information, we mean information that would affect
whether you should be influenced by a speaker's or writer's arguments, that is,
information that shapes the reasoning. Interspersed throughout the chapter will
be examples of reasoning that is not very convincing, not because of what is
said but because of what is omitted. Study the examples carefully and notice
how in each case the failure to look for omitted information would have
resulted in your making a premature and potentially erroneous judgment.
The Certainty of Incomplete Reasoning
Incomplete reasoning is inevitable for several reasons. First, there is the limitation
imposed by time and space. Arguments are incomplete because communicators
do not have forever to organize them, nor do they have unlimited
space or time in which to present their reasons.