What is a Good Argument?
There are four criteria of a good argument. A good argument must have premises that are relevant to the truth of the conclusion, premises that are acceptable, premises that together constitute sufficient grounds for the truth of the conclusion, and premises that anticipate and provide an effective rebuttal to all reasonable challenges to the argument or to the position which it supports. An argument that meets all of these conditions is a good one, and its conclusion should be accepted. If an argument fails to satisfy these conditions, it is probably a flawed one.
The Relevance Principle
One who presents an argument for or against a position should attempt to set forth only reasons that are directly related to the merit of the position at issue.
The premises of a good
argument must be relevant to the truth of the conclusion. We begin with this
criterion because there is no reason to waste time assessing the truth or
acceptability of a premise if it is not even relevant to the truth of the
A premise is relevant if its acceptance provides some reason to believe, counts in favor of, or makes a difference to the truth or falsity of the conclusion. A premise is irrelevant if its acceptance has no bearing on, provides no evidence for, or makes not difference to the truth or falsity of the conclusion.
In the terms of traditional logic, the premises of an argument are relevant if the conclusion in some sense follows from the premises. If the argument is a deductive one, the conclusion necessarily follows from the premises if the argument is patterned after a logically correct or valid form. In such cases, the premises are obviously relevant to the conclusion, because the conclusion of a correctly formed deductive argument simply spells out what is already implicit in the premises.
If the argument is an inductive one, the conclusion follows from the premises if those premises support or tend to confirm the truth of the conclusion. However, determining whether the premises of an inductive argument strongly or adequately support the truth of its conclusion depends also on how well those premises meet the other criteria of a good argument.
There are several questions that one may want to ask in an effort to determine whether a particular premise or reason is relevant. First, would the premise's being true in any way make one more likely to believe that the conclusion is true? If the answer is yes, the premise is probably relevant. If the answer is no, the premise is probably not a relevant one. Second, does the premise seem to have any connection to whether or not the conclusion is true? For example, could the premise be true and the conclusion be no more likely to be true than false-or no more likely to be a good thing to do than not to do? If so, then it makes no difference whether the premise is true or false, which is another way of saying that the premise is irrelevant. Finally, even if the premise is true, should it be a consideration in the determination of whether or not the conclusion of the argument is true? For example, does the fact that a new movie has enjoyed the greatest box office success in history be a consideration in the determination of the quality of the film? If the answer is no, then the premise is an irrelevant one. If the answer is yes, which is unlikely in this case, then the premise should be regarded as relevant.
The Acceptability Principle
One who presents an argument for or against a position should attempt to use reasons that are mutually acceptable to the participants and that meet standard criteria of acceptability.
The second test by which
we determine the quality of an argument is whether the reasons set forth in
support of the conclusion are acceptable. A reason is acceptable if it is the
kind of claim that would be accepted by a rational person in the face of all the
relevant evidence available. This criterion is similar to the criterion imposed
upon jurors in a criminal trial. The judge asks the jury to accept a claim
presented by the prosecutor and evaluated by the defense attorney if it is a
claim that a reasonable person in the face of all the relevant evidence available
would accept as true or would treat as beyond reasonable doubt.
What seems rational to some people, of course, does not always seem rational to others. For that reason we suggest a number of specific guidelines that should be helpful in achieving greater agreement on the question of what is or is not an acceptable claim. These guidelines are what might be called "standard criteria of acceptability." One who takes on a task of assessing the acceptability of premises should carefully follow such standards, just as in criminal cases lawyers and judges must be guided by rules of evidence and juries by specific jury instructions.
Criteria of Acceptability
A premise should be acceptable to a rationally mature person if it expresses any of the following:
A claim that is a matter of undisputed common knowledge.
A claim that is a matter of one's own personal knowledge or observation.
A claim that is adequately defended in the same discussion or at least capable of being adequately defended on request or further inquiry.
A conclusion of another good argument.
An uncontroverted eyewitness testimony.
An uncontroverted report from an expert in the field.
A relatively minor claim that one has no reason to question and that seems to be a reasonable assumption in the context of the argument.
Clearly, there are a number of distinctive types of claims that a reasonable person should find entirely acceptable. There is no good reason not to accept a claim that is virtually undisputed by the community of competent inquirers. Neither would a reasonable person not accept that which he or she knows to be true from personal observation. And even though one might not have the evidence present in the argumentative context, it is reasonable to accept a claim that could be easily defended by reference to a readily accessible authoritative source.
Conditions of Unacceptability
An alternative way of employing the acceptability criterion is to apply what might be called the "conditions of unacceptability." A premise should be unacceptable to a rationally mature person if it expresses any of the following:
A claim that contradicts the evidence, a well-established claim, or a credible source.
A claim that is inconsistent with one's own personal knowledge or observations.
A claim that contradicts other premises in the same argument.
A questionable claim that is not adequately defended in the context of the discussion or in some other accessible source.
A claim that is linguistically confusing.
A claim that is no different from the conclusion that it is used to support.
A claim that is based on a usually unstated but highly questionable assumption.
As can be seen, there
are also several distinctive types of claims that a reasonable person should not
accept. A claim that is expressed in language that is confusing is not
acceptable, for we obviously cannot accept a claim that we do not understand.
A premise that is no different from the claim it allegedly supports cannot be acceptable-mainly because the supporting claim, is the claim it supports. An example of this "question-begging" device is as follows. "One shouldn't vote for oneself in a fraternity election, because it just isn't appropriate to do that sort of thing." The reason given for the conclusion is an unacceptable claim, because it is no different from-indeed, it is the same claim as-the one that is at issue.
Neither should one accept a claim that is based upon a so-called "unwarranted assumption," wherein a questionable assumption is implicitly used to support the claim at issue. An example would be a claim that Scott is a good singer, because he is a member of a very good-sounding choir. In this case the arguer has made the unwarranted assumption that what is true of the whole is true of each of its parts. Since that assumption is an unacceptable one, the claim that rests upon it should also be unacceptable.
There are a number of specific questions to ask when trying to decide whether a premise is an acceptable one. First, is this a claim about which there is any serious dispute? Although 98 percent of the American people believe or accept the claim that God exists, the question of whether God exists is in serious dispute by competent scholars. In contrast, there is no serious dispute about whether aspirin tends to reduce fever. Second, is there any reason for not accepting the claim? For example, is there any known evidence, reliable authority, personal experience, or other consideration that raises any serious questions about the truth of the premise? If yes, the premise would not be acceptable until those conflicts are resolved. If no, there would be no good reason not to accept the claim and move on.
The premises of an argument, then, should be regarded as acceptable if each of them conforms to at least one of the criteria of acceptability and if none of them conforms to a condition of unacceptability.
One who presents an argument for or against a position should attempt to provide reasons that are sufficient in number, kind, and weight to support the acceptance of the conclusion.
Once one has examined an
argument for the relevance and the acceptability of the premises, there is still
plenty of work to do. Relevant and acceptable premises do not necessarily
make a good argument. An argument must also meet the demands of the sufficiency
criterion. 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. Additional relevant and acceptable premises may
be needed to support a particular conclusion.
The feature of the sufficiency criterion that is most difficult to apply is the assignment of weight to each piece of supporting evidence. Indeed, disagreement over this issue probably causes most of the problems in informal discussions. What one participant regards as the most important piece of evidence, another may regard as trivial by comparison with other considerations. It is therefore not likely that we will come to closure in our disputes until we come to some kind of agreement about what weight to give to critical kinds of relevant and acceptable evidence used in support of our conclusions.
There are many specific ways in which an argument may fail to satisfy the sufficiency criterion. For example, the premises may provide evidence that is based on too small a sample or on unrepresentative data. The evidence may be simply anecdotal-that is, based entirely on the personal experience of the arguer or a few people of his or her acquaintance. The evidence could also be based on a faulty causal analysis of a situation. Perhaps the most common way of violating this criterion is found in arguments in which crucial evidence is simply missing.
There are several questions to ask when applying the sufficiency test to a particular argument. First, are the reasons that are given, even if they are relevant and acceptable, enough to drive one to this particular conclusion? Second, is additional evidence of the same kind needed to support the conclusion? Third, is the evidence presented flawed by some kind of faulty causal analysis? Finally, is there some key or crucial evidence that is simply missing from the argument that must be included as one of the premises in order for one to accept the argument's conclusion?
The Rebuttal Principle
One who presents an argument for or against a position should attempt to provide an effective rebuttal to all serious challenges to the argument of the position it supports and to the strongest argument on the other side of the issue.
Meeting the demands of
the principle of rebuttal is perhaps the most difficult of all argumentative
tasks. Since an argument is usually being presented against the background that
there is another side to the issue, a good argument must meet that other side
head-on. An argument is not a good one if it does not anticipate and effectively
rebut, or successfully blunt the force of, criticisms of the argument and the
position it supports. A complete argument would even rebut the arguments
mustered in behalf of alternate positions on the issue in question.
Most reasonably clever people can devise what appears to be a good argument for whatever it is that they want to believe or want us to believe. For example, virtually every jury in a criminal trial is impressed by the quality of the prosecutor's argument. If that were the only argument heard, nearly all juries would convict the accused. It is the defense attorney's rebuttal and the prosecutor's response to that rebuttal that give the jury the whole picture and the proper basis for decision.
If you look at most controversial issues and the arguments in their behalf, you will notice in many cases that most of the opposing arguments meet the first three criteria of a good argument. They each have relevant, acceptable, and sufficient premises. This suggests that almost any argument can be made to look good if it does not engage the principal challenges to its strength. Therefore, the ultimate key to distinguishing between a good and a not-so-good argument is to determine how well the rebuttal criterion is met.
The fact that arguments can be more or less equally attractive as long as they are devoid of rebuttal premises may partly explain why so many people are skeptical about the ability of arguments to settle controversies. It all seems to come out even. But it is not likely that there can be good arguments in support of both sides of opposing or contradictory positions, because at least one of the arguments presented will not be able to satisfy the rebuttal criterion. Probably only one of them will be able to effectively answer the challenges of the other. Otherwise, we could find ourselves in a situation where each of two contradictory positions would merit our acceptance. But we cannot logically or practically tolerate such a situation. It simply cannot be the case, for example, that a particular abortion is both wrong and not wrong. The solution to the dilemma of "double truth" is therefore to be found by determining which of the arguments can most effectively meet the most serious challenges to its own position or can damage the strongest arguments for the other position.
What should be regarded as a serious challenge? It is one that reasonable persons, following all the guidelines suggested in this code and text, would regard as appearing forceful enough on the surface to require some answer. Even if the arguer thinks that there is an effective response to the criticism, he or she should treat it as a serious challenge, if for no other reason than to ultimately convince its holder and others of its weakness. Indeed, a good argument would anticipate the most obvious challenges and use the rebuttal premise to blunt their force. It not only shows that one has done one's homework, but it disarms the critic in advance. The alleged "big guns" are rendered ineffective before they are fired.
What would be an effective response? It is one that a reasonable person, following all the guidelines suggested in this code and text, would accept as seriously damaging or destroying the force of the criticism or counterargument. In other words, an effective response to a serious challenge is one that should cause a reasonable person to no longer regard the challenge as a serious one.
The rebuttal should be the primary driving force behind the formation of every argument. In this way one will have a constant reminder that an argument is not finished until one has finished off the counterarguments. But, unfortunately, the rebuttal premise is the most frequently neglected feature of arguments. There are perhaps several reasons why this element is missing from our arguments. First, we can't think of any effective answers to the challenges to our position, so we just keep quite about them. Second, we don't want to mention the contrary evidence for fear that our position will be weakened by bringing it to the attention of our opponents. Finally, we are so convinced by our own position that we really don't believe that there is another side to the issue. Whatever might be the reason, an argument that lacks this feature cannot be a good one, for in order for us to be properly convinced of anything, we must first look at all the evidence. And we have not looked at all the evidence until we have looked at the contrary evidence.
There are several ways that arguments can fail to meet the rebuttal criterion. Several diversionary tactics are commonly used by those wishing to avoid the responsibility of rebuttal. For example, arguments that respond to a serious challenge by misrepresenting the criticism, by bringing up trivial objections or a side issue or by resorting 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, there are those who try to avoid responding to a criticism by attacking the critic instead of the criticism. All of these approaches are clear violations of our obligation to respond honestly to the arguments of our opponents.
There are several questions that one must ask and answer in applying the rebuttal principle to an argument. First, what are the strongest arguments against the position being defended? Second, does the argument address the counterarguments effectively? Third, what potentially serious weaknesses in the arguments for the position might be raised by an opponent? Fourth, does the argument itself recognize and address those possible weaknesses? Finally, does the argument show why arguments for alternative positions on the issue are flawed or unsuccessful?
In summary, it is our position that an argument that violates any one of these four principles of a good argument is a flawed one. Yet the fact that it is flawed does not mean that it could not be turned into at least a better argument by amending it.
["Attacking Faulty Reasoning", By T. Edward Damer]