For the purposes of critical thinking, all sentences can be divided into
those that can be true or false, and those that cannot. Only a few
sentences cannot be true or false: commands ("Just do it."),
exclamations ("Far out!"), and questions ("Why not?").
Exclamations and commands are rare in the persuasive appeals that we call
arguments in critical thinking, though they are much more
frequent in the kind of arguments you get into at home or in a bar or
after an accident, where there is a good deal less analysis than anger.
Questions can be found more frequently in critical thinking, but these are often rhetorical
questions: questions asked in such a way that they make a point without
requiring an answer, or questions with answers so obvious they don't
really need to be asked.
Sentences that can be true or false--the vast majority of all sentences
in critical thinking--are called statements or claims. Note
that you don't need to know whether a statement is true or false,
just that it has the form of sentence that can be true or false. We
may never know the truth of such sentences as "Before he died, Elvis was
thinking of becoming a vegetarian" or "The universe is younger than its
oldest galaxies"; we may not even completely understand them. But as long
as they have the possibility of being true or false, such sentences are
We can further categorize statements by three qualities:
- whether they are verifiable, evaluative, or advocatory claims;
- whether they are specific or, if non-specific, whether the qualification
strengthens or weakens the claim;
- whether they serve as conclusions, premises, or support in an argument.
In this section, we will be focusing on the first two qualities
only. You can find more information about conclusions, premises, and
support in the section on the structure
of an argument, and you can find help in distinguishing premises and
conclusions in the section on identifiers.
Qualified and Specific Statements
Specific claims contain or imply
language or figures of an exact nature:
45% of the people surveyed supported the reforms.
One-third of the investment has been lost.
This marked the first time that India successfully orbited
In those three sentence, "45%," "one-third," and "first"
represent specific information. Such statistical statements are powerful
and persuasive expressions in an argument, but they are also easy to attack,
because a single example to the contrary is sufficient to refute them.
The most common specific statements are
universal ones, in which the figure involved is either "100%" or "0%," usually expressed by words
such as always, never, all, none, everyone, no one, and so on. For
more on this, see the section on Universal
Non-specific claims are ones in which no specific
number is cited; as a result, they are often more difficult to attack.
Consider the following examples:
- 49% of those casting ballots voted for Kennedy.
- Approximately 49% of those casting ballots voted for
- More than 49% of those casting ballots voted for Kennedy.
- Less than half of those casting ballots voted for Kennedy.
- Kennedy received more votes than did Nixon.
Only the first example above is a specific claim.
The second qualifies that specific claim with the word "approximately,"
making the statement weaker but harder to disprove. The
last three examples are all comparative statements, a type of qualification
that operates by comparing the subject of the statement with something else
(49% of the votes vs. "more than 49%," half the votes vs. "less than half,"
the votes for Kennedy vs. the votes for Nixon). Comparative and other
non-specific claims are usually harder to disprove than specific claims,
but not always; often, they are also more effective in an argument.
A claim with a modifier is considered qualified whether it
is specific or non-specific. Non-qualified claims have no modifiers at all:
"The investment has been lost" or "Kennedy received votes." These sound
universal, but may not be.
Note that many claims appear to be specific, but are
usually intended to be non-specific. Consider these examples:
All of these examples convey an implied "all" or "always."
But even if we said, "Jacques is always a good boy," we wouldn't
be surprised to find out about the time Jacques wasn't good. And though
Americans may be rich and well-educated as a group, compared to
many other peoples in the world, we surely recognize that there are many
Americans individually who are either not rich or not well-educated.
Generally speaking, apparently specific claims should be understood
as non-specific when they deal with personal behavior or group attributes
because humans (and other organisms) are individually inconsistent and
collectively diverse. To some extent, this is true of other populations,
including manufactured items like automobiles. We understand that
"Mercedes are reliable cars" doesn't mean "100% of Mercedes are reliable
cars." Yet "Mercedes have aluminum-head engines" may well mean "100% of
Mercedes have aluminum-head engines"; and (most interestingly) we may be
willing to put "all" in front of the statement, "Mercedes are expensive
cars," even though we know that a heavily damaged Mercedes can be bought
for only a few dollars. The point here is that, sometimes, context and
convention may affect our understanding of even simple statements.
The job of a critical thinker is to understand the statements as they
were meant, rather than insisting on a purely literal construction.
Exercises: Specific, Universal,
Non-Specific, and Comparative Statements
Statements of Verification and
Fact and Opinion. In critical thinking, the difference between
what are commonly called "facts" and "opinions" is not great--if, indeed,
it exists at all. Both "facts" and "opinions" can be used to support
arguments, and sometimes strong expert "opinions" can outweigh weak or
inconsistent "facts." Indeed, considering that much of what we know about
the physical sciences is based on hypotheses--that is, opinions that cannot
be confirmed--you might wonder why we bother distinguishing between "fact"
and "opinion" at all.
Verification and Evaluation. A more important distinction for
critical thinking is between claims that are thought to be verifiable, and
those that are presented as evaluative. In this sense, verifiable
claims are those that can be confirmed either by observation or by
reference to established sources, such as books.
Evaluations are statements of taste and
interpretation. Notice that opinions can be expressed sometimes as
statements of verification and sometimes as statements of evaluation.
Consider the following claims:
- "Willa thinks that's a shade of blue."
- "Willa thinks that's a lovely shade of blue."
- "That's a shade of blue."
- "That's a lovely shade of blue."
The first two are clearly opinions, but they are expressed as
statements of verification, because the issue is whether that is
what Willa thinks, not what the color is. The third one is also a
statement of verification, because (for most people) "blue" is
something ascertainable by observation. But the fourth claim is a
statement of evaluation, because what is "lovely" is a matter of
taste. And it doesn't matter whether the claim is true or false--that is, a false
statement of verification is not a statement of evaluation. All four of
our examples can be false--Willa might think otherwise, for the first two,
and the color might be red, for the second two--but they are nevertheless
three statements of verification, followed by a statement of evaluation.
Advocatory claims are a special category of evaluative claims which deal with morality, ethics, duty, and other sorts of statements involving compunction, in that advocatory claims express what ought or ought not to be or to have been. Thus, "You are free" is a claim of evaluation, but "You should be free" is an advocatory statement. Advocatory claims usually include the word "should" or "ought" (though not all claims with "should" or "ought" in them are advocatory). Notice, however, that "You should be free" may be expressed in two claims as "Free is good" and "You should be whatever is good." Since all advocatory claims take this form--an evaluative claim like "Free is good" and some element of the generally accepted maxim that "You should be or do whatever is good or right or proper, and you should not be or do whatever is not good or right or proper"--we will simply treat advocatory claims as evaluative ones, with the maxim understood.
The point of categorizing statements into specific and qualified, on
one hand, and verifiable and evaluative, on the other, is to
understand better the arguments in which they appear. We have already seen
that specific claims are the most persuasive but also the most easily
refuted. Correctly identifying such statements helps to indicate what needs
to be done to attack and defend an argument. Knowing if a statement is one
of verification or evaluation helps ensure a consistency of
argument, because if the conclusion is a statement of verification, it must
be supported by at least one premise that is a verifiable claim; and
so too with conclusions of evaluation.
Exercises: Statements of
Verification and Evaluation