In our daily lives,
we’re constantly hearing or making persuasive arguments. We may be listening to
a colleague’s argument for why we should support one of her initiatives. We may
hear an argument for why we should buy a certain product. Or we may need to make
our own argument to get approval for one of our projects.
How should we evaluate
arguments that people make to persuade us? And how should we construct our own
arguments to be the most effective?
T. Edward Damer shares an
excellent framework for creating good arguments in his book Attacking Faulty Reasoning. Damer begins by explaining what an argument is. At
its core, an argument consists of a conclusion and one or more premises, or
claims. The conclusion is what the communicator wants his or her audience to
accept, and the premises are the reasons for believing the conclusion to be
true. According to Damer, here’s the formal definition of an argument:
“An argument is constituted by two or more explicit
and/or implicit claims, one or more of which supports or provides evidence for
the truth or merit of another claim, the conclusion.”
So how do you craft a good argument? Damer shares the five
principles for developing a good argument:
1. Structure
2. Relevance
3. Acceptability
4. Sufficiency
5. Rebuttal
Let’s look at each of these principles in more detail.
A good argument must meet the fundamental structural
requirements of a well-formed argument.
“Such an
argument does not use reasons that contradict each other, that contradict the
conclusion, or that explicitly or implicitly assume the truth of the
conclusion.”
To evaluate any argument for whether it violates the
principle of Structure, ask the following questions:
Does the
communication include at least one reason to support the conclusion as being
true?
If it doesn’t,
then it’s not an argument — it’s merely an opinion. An unsupported conclusion
is an opinion; a conclusion supported by reasons is an argument.
Could any
of the key premises be interpreted as making the same claim as the conclusion?
If so,
then it’s a “circular argument” — there’s no independent reason given to
support the conclusion. Since A, therefore A. No one is likely
to use the exact same words in both the premise and the conclusion, so you need
to ask yourself if a premise can be interpreted as making the same claim as the
conclusion. “Joe is nuts,” Gary says. “Why do you say that?” I ask. “Because
he’s so crazy,” Gary replies. Since A, therefore A.
Do any of
the premises contradict another premise or does the conclusion contradict any
of the premises?
2.
Relevance
The reasons that a communicator provides as part of his or
her argument must be relevant for the truth or merit of the
conclusion. What makes a premise relevant?
“A premise
is relevant if its acceptance provides some reason to believe, counts in favor
of, or has some bearing on the truth or merit of the conclusion. A premise is
irrelevant if its acceptance has no bearing on, provides no evidence for, or
has no connection to the truth or merit of the conclusion.”
To assess whether an argument violates the principle
of Relevance, ask these two questions:
If the
premise were true, does it make you more likely to believe that the conclusion
is true?
If yes,
the premise is probably relevant. If no, then the premise is probably not
relevant.
Even if the
premise were true, should it be a consideration for accepting the truth of the
conclusion?
If no, then
the premise is probably not relevant. “Jerry is over 6 ft. tall. So he must be
good at basketball.” “Avatar is an artistic masterpiece. After all,
it was the highest grossing film of the year.”
3.
Acceptability
The reasons that a communicator provides in his or her
argument should be likely to be accepted by a mature, rational adult. As Damer
writes, a premise should be acceptable to a mature, rational adult if it meets
the following standards of premise acceptability:
“A claim that
is a matter of undisputed common knowledge.”
“A claim that
is confirmed by one’s own personal experience or observation.”
An
“uncontroverted eyewitness testimony,” or an “uncontroverted claim from a
relevant authority.”
“A relatively
minor claim that seems to be a reasonable assumption in the context of the
argument.”
By contrast, a premise should be rejected by a mature,
rational adult if it meets the following conditions of premise
unacceptability:
“A claim that
contradicts credible evidence, a well-established claim, or a legitimate
authority.”
“A claim that
is inconsistent with one’s own experiences or observations.”
“A claim that
is based on another unstated but highly questionable assumption.”
An argument meets the acceptability principle when each of
its premises conforms to at least one of the standards of acceptability
and none of its premises conforms to the conditions of
unacceptability.
To assess whether an argument violates the principle of Acceptability,
ask the following questions:
- Is the premise provided one that a mature, rational adult would likely accept?
- What evidence is provided as part of the claim, and does it conform to the standards of acceptability or the conditions of unacceptability?
- Is the premise based on an unstated assumption that a mature, rational adult not be willing to accept?
4.
Sufficiency
A communicator making an argument should provide reasons
that are sufficient to justify the acceptance of his or her conclusion.
“There must
be a sufficient number of relevant and acceptable premises of the appropriate
kind and weight in order for an argument to be good enough for us to accept its
conclusion.”
This principle is one of the most difficult to apply,
because it’s a judgment call. There are no black-and-white guidelines for what
constitutes a “sufficient” number and weight of reasons to accept a conclusion.
Often, it’s a disagreement about the weight or sufficiency of the premises in
an argument that prevents two intelligent and well-meaning people from reaching
the same conclusion based on the same available evidence.
To evaluate whether an argument violates the principle of
Sufficiency, ask the following questions:
Are the
reasons provided enough to drive to the arguer’s conclusion? If not, the argument violates the
sufficiency principle.
Is the
premise based on insufficient evidence or faulty causal analysis? Some premises provide evidence
that is based on too small a sample or unrepresentative data. Or the evidence
is based on the personal experience of the arguer, or of a small set of
acquaintances that the arguer knows. The premise may be based on faulty causal
analysis — assuming A caused B, even though the two events were unrelated.
Is some key
or crucial evidence missing that must be provided in order to accept the
argument?
5.
Rebuttal
A good argument includes an effective rebuttal to all
anticipated serious criticisms of the argument.
“An
argument cannot be a good one if it does not anticipate and effectively rebut
or blunt the force of the most serious criticisms against it and the position
that it supports… A good arguer should be constantly mindful of the fact that
an argument is not finished until one has ‘finished off’ the criticisms and
counterarguments.”
There are multiple ways that an argument can violate the
Rebuttal principle. Arguers often use diversionary tactics instead of making
effective rebuttals.
“For
example, arguments that misrepresent the criticism, bring up trivial objections
as a side issue, or resort to humor or ridicule are using devices that clearly
fail to make effective responses. The same can be said of those arguments that
ignore or deny the counterevidence against the position defended. Finally, some
arguers try to avoid responding to a criticism by attacking the critic instead
of the criticism.”
To assess whether an argument fails to meet the Rebuttal
principle, ask the following questions:
Does the
argument provided address the strongest counterarguments effectively?
Does the
arguer anticipate and address serious weaknesses in the argument?
Does the
argument show why alternative positions are flawed?
Making
your own argument stronger
We can use the five principles above to evaluate arguments
that others present to us. But how do we strengthen our own arguments when we
craft them? Using each principle, Damer provides some suggestions for how to
improve our arguments.
Structure: Explicitly call out your conclusion and
the supporting reasons, so that they are easy to recognize and follow. Ensure
that your premises (1) do not contradict each other or the conclusion, and (2)
do not assume the truth of the conclusion. Make explicit any key assumptions
that you’re using.
Relevance: Ensure that all materials you’re
presenting as part of your argument are relevant. Cut out anything that’s not
relevant. Don’t weaken your argument by including irrelevant premises.
Acceptability: Whenever possible, substitute less
controversial claims for more controversial ones. Soften, if possible, any
absolute claims to make them more acceptable. (e.g. “most politicians” instead
of “all politicians”) Don’t use highly questionable evidence or assumptions.
Sufficiency: Continue adding relevant premises if
they contribute to the number and weight of the reasons that drive to your
conclusion. Put yourself in your audience’s place, and ask if the reasons are
sufficient to accept your conclusion. If an important premise is controversial,
support it with sub-premises and additional evidence.
Rebuttal: Be as exhaustive as necessary in your
rebuttal. Some arguments may need to rebut a single criticism, but more
controversial or divisive issues may require multiple rebuttals. Declare up
front what the weakest parts of your argument are and proactively address them
to blunt the force of your opponent’s counterarguments.