The focus on reason distinguishes argumentation from other modes of rhetoric. While other modes of rhetoric may focus on such elements as sequence (narrative) or comparison (metaphor), argumentation focuses on the reasons a person uses to support a claim. Although reasons are presented in other forms of rhetoric, reason is the primary element that makes argumentation a distinct form of rhetoric.
Historically, reason has been treated in different ways. In Classical Greece to Renaissance Europe, two kinds of reasoning were developed. One kind--which is now called formal, deductive logic--was developed to solve mathematical and scientific problems. The second kind-- referred to by some writers as practical logic or sometimes informal logic--was developed to deal with issues of human affairs ranging from politics to matters of everyday life.
In the Classical as well as in the Renaissance Periods these two systems of reasoning stood side by side, each respected as a proper tool for use in a certain context. Then, during the Modern Period dating from the mid-1600s to the mid-1900s, practical reasoning lost respect among intellectuals. For over three hundred years, formal, deductive logic was the only game in town.(1) Change comes slowly after three hundred years but today thinkers from a variety of disciplines ranging from philosophy to literary criticism to psychology are demonstrating the usefulness of more than one system of logic.
For some, a focus on reason is the same as a focus on logic. Some consider reason and logic so similar that one term is frequently substituted for the other and for many, logic is synonymous with formal, deductive logic. Although the term, "reason" is purposively chosen over the term "logic," a brief discussion of formal deductive logic will aid our understanding of reasoning in everyday life.
The name, "formal logic," derives from the word "form." Formal logic is so named because the test of the logic is in the structural form of the argument. An argument in the proper form is said to be valid whereas an argument in improper form is said to be invalid. In this sense, formal logic has "a character like that of pure mathematics."(2)
Using formal logic, a person begins with statements assumed to be true then infers a conclusion based on those statements. Formal, deductive logic is a method of testing inferences but not the premises from which the inferences were made. Another way to make the same point is to say that logic is rational, not empirical; that logic deals with how we make inferences, not with the facts we observe.
Formal, deductive logic is a method of testing inferences. For instance, consider the claim, "If P then Q." Formal logic is a means of testing the "then" part of this equation; in other words, it tests the inference from P to Q. We assume that P is true and test the relationship between the truth of P and the truth of Q.
Formal, deductive logic does not test the truth of a beginning premise; it does not test the "if" part of the proposition "If P then Q." We assume--for the sake of the argument--the truth of the premises and test the relationships among or between premises. Logicians sometimes claim that formal, deductive logic establishes the truth of premises by constructing further arguments which have the original premises as their claims. Philosopher Stephen F. Barker explains this process in the following manner:
My opponent, even if [s]he grants that my conclusion follows from my premise, may question whether my premise is true; [s]he may say that [s]he will not accept my conclusion until I prove my premise. If [s]he challenges my premise in this way, it becomes my duty to try to construct a new argument to establish that premise, that is, a new argument that will have a new premise (or premises) that will have as its conclusion the premise of the first argument. I would hope to be able to choose for my new argument a new premise that my opponent will not challenge; but if [s]he challenges this new premise also, then I must try to prove it too.(3)
Accordingly, if an arguer asserts, "If P then Q" and someone responds, "Yes, but I don't believe P," the arguer might then construct a further argument such as, "If R then P." When the respondent says "But I also don't accept R," the infinite regression possible in this process becomes rather obvious. If our premise is challenged, we must find another premise which will have our original premise as its conclusion. And if the second premise is challenged, we must find a third premise from which we can infer the second. And so on ad infinitum. Ultimately, if we are to make any progress, we must find a situation where the truth of our premises are assumed. Logic can test inferences, but it cannot test the truth of the premises on which the inferences are based.
To further illustrate this concept, consider the concepts of truth, validity, and soundness. A formal, deductive argument is said to be sound if it makes valid inferences from true premises. In other words, an argument which begins with true premises then makes valid inferences is said to be a sound argument. Soundness is the criteria that separates a good argument from a bad one and truth and validity are the necessary and sufficient conditions of soundness. However, since formal, deductive logic only tests the validity of an inference, it is only relevant to one of the two necessary conditions of a sound argument. Thus, determining "truth" of premises is beyond the reach of formal, deductive logic.
Formal logic is not the only tool needed to address practical, human concerns. In the realm of human affairs, we cannot assume the truth of premises. An arguer's initial premise frequently is the most problematic aspect of the argument. A complete system of argumentation must include a substantive dimension to account for, among other things, the acceptability of these initial premises. Such a substantive element is absent from logic.
In its simplest form, an argument consists of a claim and a reason to support that claim. An arguer begins with a premise and makes an inferential leap to a claim. The acceptability of the premise (what formal logicians prefer to call "truth") involves the substantive dimension of argumentation. The cogency of the inferential leap (what formal logicians prefer to call validity) involves the logical dimension. Thus, substance and logic are two interrelated dimensions of reason.
Substantive Dimensions of Argumentation
Examining the substantive dimension of an argument involves investigating the facts and evidence on which the premises are based. Are the facts accurate? Is the evidence worthwhile? Are the premises reliable? Are the authorities who reported the facts credible?
As an example, consider an argument that claims Oswald was not alone in the plot to assassinate JFK. The premises for such an argument might include the testimony of Silvia Odio. Odio claimed that approximately two months prior to the assassination, she met Oswald in the company of two Cubans, one called Angelo and the other called Leopoldo. She also claimed that the day after the meeting, she received a call from Angelo in which he said he, Leopoldo, and Oswald had discussed killing the President.
An investigation of the substantive dimensions of the argument would involve careful study of the details of the premises in order to determine their accuracy. One might begin by questioning the credibility of the reporter. Is Silvia Odio a reliable person? Is her story believable? Can anyone else corroborate her story? Did she have anything to gain by falsifying the story? After examining the credibility of the reporter, one might examine the details of the story for their internal and external consistency. Are there contradictions within the story? Is the story consistent with other known facts? Could Oswald actually have been in Dallas on the day Odio claimed to meet with him? These are some, but not all, the questions one would ask when looking at the substantive dimensions of this argument.
Logical Dimensions of Argumentation
Examining the logical dimensions of an argument involves inspecting the connection between the premise and the claim. What kind of claim is being made? What kind of connections would one ordinarily expect given this kind of claim? Are those connections adequately made?
The claim in the above example is one of sign. The fact that Oswald was seen in the presence of two Hispanic men two months prior to the assassination and the fact that one of those men called Odio the next day and reported that the three of them had discussed the assassination is a sign that they were involved with Oswald in the plot to murder the president. Does the presence of these two signs (the two men's association with Oswald and their discussion of the murder) indicate their presence in the plot to kill the president? This is primary question involved in the investigation of the logical dimension of this argument.
Both the substantive and logical dimensions of argument are as important to the concept of reason as reason is to argumentation itself. Reason without substance is as inadequate as reason without logic. Thus, the system of practical reasoning described below attempts to incorporate both dimensions.
The system of practical reasoning used in this text is based on a model developed by Stephen Toulmin(4) and later modified by Albert R. Jonsen and Stephen Toulmin.(5) This model describes some important elements of reasoning as they relate to argumentation. Because it is only a model, it is only a rough approximation of those elements and their relationships to one another. The model is not intended as a descriptive diagram of actual arguments for a variety of reasons. First, it only describes those elements of an argument related to reasoning. It does not describe other important elements such as expressions of feelings or emotions unless those expressions are directly related to reasoning. Second, the model only describes the linguistic elements of reasoning. To the extent that an argument includes significant nonverbal elements, they are not covered by the model.(6) Third, the model only applies to the simplest of arguments. If an argument is composed of a variety of grounds related to the claim in different ways, the model may not apply well if at all. Even given these shortcomings, this model has proven itself useful for describing some of the key elements of arguments and how they function together in terms of reasoning. The following diagram illustrates the model of practical reasoning:
A Model of Practical Reasoning
The model of practical argument includes four important elements: claims, starting points of argument, warrants, claims, and reservations. Claims have already been discussed in Chapter Three. However, the notion that argumentative claims are always provisional conclusions needs to be reinforced. Because this is a model of practical reasoning, claims are always made with certain degrees of certainty and frequently are relevant only to people's values and actions in specific circumstances. Saying that a claim is provisional means that it is probable rather than certain and that it generally applies to individual circumstances and less often to absolute and universal moral principles.
Aside from claims, the other three elements (starting points, warrants, and rebuttals) generally fall into a broader category of premises. Starting points, warrants, and reservations all are certain kinds of premises but ones that have different functions in the argument. Consideration of each of these kinds of premises will clarify how they function individually and in combination with one another.
Argumentative Starting Points: Facts and Values
The concept discussed here has been referred to by a number of different terms: "the starting point of argument,"(7) "data,"(8) and "grounds."(9) Regardless of the term used to describe the concept, starting points of argument include facts and values and any other kinds of grounds on which the argument is based. As discussed earlier, these facts and values may be ones the arguer discovered in a process of argument invention, or they may be drawn from claims the arguer has created from earlier arguments. Generally, starting points of argument consist of facts and values.(10)
Factual Starting Points
These starting points are considered factual because the audience considers them so. If the audience does not consider a starting point factual, the arguer is then obliged to construct an argument which has as its conclusion, the statement of fact. Exhibits, reports and statistics, and expert testimony are among the types of factual starting points used by arguers.
Exhibits(11) are kinds of facts that can be used as starting points for arguments. Exhibits are physical evidence the arguer and the audience can touch, see, taste, smell, or hear. For instance, a bullet a custodian removed from a stretcher in Parkland hospital in Dallas (labeled Commission Exhibit 399 CE 399) was examined by the Warren Commission. Not only the Warren Commission, but many later groups have studied this bullet to try to determine from its characteristics whether or not it could have passed through John Kennedy and continued on to seriously wound Texas Governor John B. Connally. Other examples of exhibits include fingerprints left on a murder weapon, dinosaur bones discovered by an archeologist, or a black box from a crashed airliner.
Exhibits are frequently considered strong starting points for arguments because they are subject to inspection by both arguer and audience. But most of the time, arguers are unable to base their arguments on this kind of a starting points. More often, they must rely on the testimony of a human observer to describe and interpret the evidence.
Reports and statistics are starting points that rely on human testimony. An arguer who was not present to observe the events must depend on eye witness and ear witness testimony of a variety of events ranging from the battle of the Little Big Horn to the Oklahoma City bombing to the standoff in Waco. Because the arguer did not observe these events first hand, the credibility an audience is willing to attach to the reports is largely due to the believability of the person reporting and interpreting the events.
Statistics are a special kind of evidence in which the report is reduced to numbers. Statistics are a frequent source of starting points for arguments. How many people who smoke cigarettes develop lung cancer compared to those who do not smoke? How many traffic fatalities occur in automobiles with airbags as compared to automobiles without airbags? What are the murder rates in states with capital punishment as compared to the murder rates in states without capital punishment? We confront statistics so frequently that we sometimes forget a statistic does not have an independent existence apart from the persons who report and interpret them. Not only should we consider the credibility of the person reporting the statistics, but we should be interested in the methods that person used to generate the statistics.
Expert testimony (or even a non-expert testimony) sometimes is used as a starting point for an argument. Someone may argue that the Broncos are the best team in professional football because John Elway says so. Someone may argue that O. J. Simpson murdered Nicole Brown-Simpson because Mark Fuhrman said so. In their pure form, these examples are weak starting points since they are based totally on a person's testimony without consideration for the basis of that testimony. A critical audience would ask, "What does Elway have to go on?" and "On what does Furman base his testimony?" Still, testimony without regard for its basis can be used as a factual starting point for an argument, albeit a rather weak one.
Evaluative Starting Points
Evaluative starting points are different from factual starting points in that they deal with the preferred rather than with the real. Values, value hierarchies, and the principles that order value hierarchies are all potential evaluative starting points of arguments.
Values are concepts people use to evaluate objects. In the abstract, people might say they value freedom of choice, or privacy, or truth. These abstract values can then be made more concrete by attaching them to objects.
A person should have the freedom to choose to commit suicide.
The Government should not invade the privacy of its citizens.
The CIA should not be allowed to keep secrets from the congress.
These statements are all examples of values being attached to objects.
Values are important to arguments because people are in a better position to make arguments if they understand and share the audience's values. These shared values can be used as starting points of arguments. If people have reason to believe the audience values freedom of the press, they have a potentially strong starting point for a claim opposing censorship of school textbooks. Even though values are important elements of arguments, knowing how the audience arranges values into hierarchies can be even more important.
Value hierarchies indicate how an audience arranges values in order of importance. An audience may value both truth and privacy, but how does the audience deal with a situation when those two values come into conflict with one another? Discovering the answer to this question is to discover part of the audience's value hierarchy. Any number of audiences might value limitations on the government's power to interfere with the individual just as any number of audiences might value economic security. Knowing these audience values is helpful in an argumentative situation, but not as helpful as knowing how the audience would arrange those values when the values come into conflict. For instance, An arguer who discovers the audience values limited government even when that government interferes with economic security is in a better position to construct an argument about reform of the Internal Revenue Service. As value hierarchies are useful in the invention and construction of arguments, knowing the principles on which the hierarchies are based can sometimes be helpful as well.
Principles that order value hierarchies sometimes are key to understanding how audiences arrange other values. Sometimes, but not always, analysis of an audience will reveal value hierarchies that are based on certain overriding principles. For instance, consider an audience known to value the right to life for all humans and the right of all humans to live in safety. Presume this audience favors capital punishment because they believe that sacrificing the lives of a few humans would enhance safety for a great number of humans. An observer might conclude that the principle of utilitarianism (the greatest good for the greatest number) is the principle on which the audience's value hierarchy is based. If that observer were constructing an argument for that audience, they might also use the principle of utilitarianism to speculate about how the audience would construct other value hierarchies as well. In this case, the principle of utilitarianism would be used as a evaluative starting point for an argument.
So starting points of argument can generally be divided into those which are factual and those which are evaluative. Factual starting points dealing with reality include exhibits, reports and statistics, and expert testimony. Evaluative starting points include values, value hierarchies, and principles which order those hierarchies. These are the elements of argument with which an arguer begins and from which an arguer begins to construct a pattern of reasoning.
Argumentative Warrants: Patterns of Reason
While the starting points of argument provide the grounds on which an arguer's claim is based, warrants provide patterns of reasoning to connect those grounds to the claim. The warrants provide the relationship between the starting point and the claim. These relationships are called patterns of reasoning. In attempts to bring order to the various patterns of reasoning that exist between grounds and claims, different writers have provided different classifications of warrants. In that regard, this text is no different. Without making any claim that these particular divisions are theoretically satisfactory (ie. mutually exclusive and exhaustive categories), this divides patterns of reasoning into eight categories: example, absence and presence, correlation, analogy, classification, authority, incompatibility, and dissociation. The eight categories are sufficient for supporting the four kinds of claims described in Chapter Three.
Reasoning from Example
Reasoning from example takes individual cases as starting points and makes a claim that is a generalization from those individual cases. Taken together, the individual cases constitute a sample of a larger class. By reasoning from example, an arguer is making a claim about the larger class based on evidence from the sample. Because a class ordinarily exhibits a pattern of regularity, the warrant allows the arguer to infer that what is true of the sample is probably true of the larger class. The claim therefore transfers the characteristics of the sample to the entire class.
An arguer who claims that college fraternity members are poor students because certain individual fraternity members have been poor students is using the pattern of reasoning by example. Similarly, an arguer who moves from evidence that students at some liberal arts colleges do better in graduate studies to a claim that in general, liberal arts colleges produce students who are more likely to succeed in graduate school, The following illustration incorporates reasoning by example into the model of practical argument.(12)
Reasoning by example can be used to support many different kinds of argumentative claims ranging from claims of definition to claims of fact to claims of relationship to claims of evaluation. Because reasoning by example is used to establish a category, it can be used to establish any kind of category: definitional, factual, relational, and evaluative.
Reasoning from absence and presence(13)
Reasoning from absence and presence begins with at least two objects, one of which is claimed to be an indicator of the other. This pattern of reasoning assumes that the simultaneous presence or absence of the two concepts supports a claimed relationship between the two. Depending on the kind of relationship being supported, the absence or presence of one concept indicates the absence or presence of the other concept.
A simultaneous presence of the two concepts can occur in a claim of sign or in a claim about a sufficient causal condition. An example of a sign relationship that might be supported by a simultaneous presence of two concepts involves a physician suggesting that the presence of a fever in a patient is an indication of a virus infection. In this case, so the physician claims, the simultaneous presence of fever and infection supports the idea that the fever is a sign of the infection.
The simultaneous presence of two concepts also can be used to support a relationship about a sufficient causal condition. For example, some might argue that money is an indicator of happiness because it is a sufficient cause; regardless of other factors, some might argue, money will lead to happiness. The warrant assumes that since money and happiness are both present in a number of cases, one (money) is a sufficient condition for the other (happiness).
In other cases, the simultaneous absence of each of the concepts can be used to support a claim about a necessary condition as in the claim that money is essential to happiness. If one could show, in this example, that the absence of money always leads to the absence of happiness, one would have a good start toward support of the claim that money is essential to happiness.
The following illustration using the model of practical argument shows how the simultaneous presence of two concepts can be used to support a claim that one is a sufficient cause of the other:
Likewise, the following example illustrates an instance where the simultaneous absence of two concepts indicates that one is a necessary condition of the other:
Reasoning from Correlation
Reasoning from correlation begins with a series of instances each of which vary according to at least two characteristics. For example, an argument from correlation might begin with data taken from a group of people who vary along two characteristics (smoking and heart disease, for example). Some of the people are smokers, some are not; some have heart disease, others do not. Assuming that the rate of heart disease can be shown to vary in relationship with the number of cigarettes a person smokes each day, one could then reason that a relationship of correlation exists between smoking and heart disease. Although correlation does not prove causation, it is one method used to support a claim of causation. The pattern of inference present in reasoning from correlation assumes that when two characteristics of an object vary in direct or inverse proportion to one another, one characteristic may be the cause of another.(14) Since this pattern of reasoning is based on the amount of variation between the two characteristics, the pattern is ordinarily used to make an argument about a contributory causal relationship.
An illustration of the use of correlation as a warrant in a claim about contributory cause is presented in the following model:
Reasoning from Analogy
The starting point for reasoning by analogy involves a minimum of two objects that are similar to one another in some important respect. Take for instance, the claim that "like Nixon before him, Clinton should be asked to resign because of his abuses of power." The two objects in this examle are Nixon and Clinton and the similarity between them is their abuses of power. The starting points in this claim are that (1) Nixon was asked to resign because of his abuses of power, and (2) Clinton has also abused his powers. The warrant in this analogy assumes that because the two objects are similar in important known regards (both Clinton and Nixon abused their powers), they ought to be similar in other regards (Clinton also should be asked to resign). This pattern of analogical reasoning is illustrated in the following model:
Reasoning by analogy can be used to support claims of similarity and other types of claims as well. Because similarity is so useful in claims of causation and evaluation, this pattern of analogy is relevant to them as well. For instance, one could use an analogy to support a causal claim. For example, one could argue that a diet including large amounts of beef can lead to heart disease. The argument might start with the data that eggs and beef both are high in cholesterol and that eggs contribute to heart disease. Reasoning by analogy, one might also conclude that a diet high in beef (like one high in eggs) can also lead to heart disease.
Reasoning by analogy also can support an evaluative argument. Beginning with two objects, one of which the audience already evaluates, an arguer can use analogy to transfer the audience's evaluation of one object to the other. For example, assume the audience (not unexpectedly) negatively evaluates murder as immoral. By creating an analogy between murder and capital punishment, an arguer can make an evaluative claim that capital punishment, like murder, is an immoral action.
Reasoning from Classification
Starting points for reasoning from classification include a specific case and a category--for instance, a specific case of a football player and the category of football players in general. The warrant assumes that the specific case will exhibit the characteristics of the category. If one argues that Joe probably will not do well in this class because he is a football player, one is arguing from classification. The following illustration demonstrates reasoning by classification:
Reasoning from classification can be used to make a variety of claims, such as a claim of causation. Starting with data about a category (for instance, substances that deposit tar into humans' lungs lead to lung cancer) and data about the inclusion of a specific instance in that category (cigarettes deposit tar into humans' lungs), one can then infer the causal claim that the specific instance will have the same effect as the general category (cigarettes lead to lung cancer).
Reasoning from classification also can be used to support claims of evaluation. One can begin, for instance, with data about the category of totalitarian governments (totalitarian governments do not respect individual rights) and information about the inclusion of a specific case in the category (fascism is a form of totalitarian government). From these starting points, one then can infer evaluations about the specific case from classification (fascism does not respect the rights of individuals).
Reasoning from Authority
Reasoning from authority takes personal testimony as its starting point. For instance, an argument might begin with Ralph Nader's statement that the Chevrolet Corvair is "unsafe at any speed." The warrant then assumes that any statement made by an authority should be taken as true. This example of reasoning by authority is illustrated in the following model of practical argument:
Because authorities testify about all sorts of claims, reasoning from authority can be used to make any kind of claim. But when testimony is used as the only pattern of reasoning in an argument, it can short cut the process of critical reasoning. In the previous example, to accept the claim that the Corvair is unsafe at any speed solely on the testimony of Ralph Nader would be uncritical. A critical consumer of arguments would, of course, ask about Nader's qualifications to make that statement but would go beyond the question of qualification to ask about the grounds of Nader's argument.
Of course, audiences cannot be critical of every word received from an authority because they might not be able to comprehend or understand the grounds for arguments in some fields. In those cases, audiences are virtually forced to rely on reasoning from authority. If an audience does not have the expertise to understand the data which underlie a claim about nuclear physics, they must base their trust in the argument on their trust in the authorities.
Reasoning from Incompatibility
Reasoning from incompatibility takes as its starting points two concepts which the arguer views as antagonistic to one another. For instance, the arguer might begin by showing how the concepts of capital punishment and the sanctity of human life are antagonistic to one another. The warrant in reasoning from incompatibility assumes that a person cannot logically hold two positions which are incompatible with one another. The arguer might claim, for instance, that one cannot logically maintain a belief in capital punishment and a belief in the sanctity of human life. This argument is illustrated in the following model of practical reasoning:
Reasoning from incompatibility can be used to support a variety of kinds of argumentative claims. Two examples of claims which can be supported by this pattern of reasoning include claims of fact and claims of evaluation. The claim of fact that O. J. Simpson is innocent of murder was supported by the incompatibility of a glove that didn't fit and the belief that the glove was worn by the murderer. A leather glove soaked with the blood of Nicole Brown-Simpson was believed to have been worn by the murderer. During the trial, the prosecutor asked Simpson to put the glove on his hand. The demonstration appeared to show that the glove was so small it would not fit on Simpson's hand. This misfit of hand and glove allowed Simpson's defense team to declare poetically "if the glove doesn't fit, you must acquit."
Reasoning by incompatibility also can be used to support a claim of evaluation. The example previously used in the model is one such case. To support an evaluative claim, an arguer starts with an object the audience has already evaluated (in the previous example, the sanctity of life) and argues that the audience cannot logically hold to that concept and some other concept (in this case, capital punishment).
Reasoning from Dissociation
Reasoning from dissociation is a special form of argument used when an arguer is faced with an apparent incompatibility. For instance, suppose one wishes to present a pro-choice argument to an audience who believes in the right to life. Because of what the audience sees as an incompatibility between the arguer's position on abortion and their own value of the right to life, they see the arguer in an incompatibility. Reasoning from dissociation attempts to divide the key concept of right to life into two concepts and to distance one from the other. For instance, the arguer might claim that the concept of life is not a single, unified concept, but two separate and distinct ones: general life (as possessed by plants and animals) and human life (as possessed by fully capable human persons). Of course, a further argument is required to show that a live fetus is more similar to animal and plant life than to that of a fully functioning human person. This example of reasoning by dissociation is illustrated in the following model of practical argument:
Reasoning from dissociation is not a very common pattern of reasoning, but is an interesting one because it relies on breaking connections rather than on establishing them. It is also fairly uncommon because it is mainly useful when an arguer needs to avoid the appearance of an incompatibility.
A few patterns of reasoning have been described in this section. The patterns of reasoning do not fit into a neat matrix such that some apply only to one kind of claim and others to another kind of claim. Taken together, however, these patterns of reasoning are sufficient to allow an arguer to make all of the kinds of claims presented in the previous chapter.
Argumentative Reservations: Exceptions Based on Circumstances
Reservations, exceptions to one's claim, are important in a variety of kinds of argument, but they are particularly important in arguments about ethical and moral action. Claims about ethical and moral action can be framed in either particular or universal terms. Claims about a universal moral action might be "Capital punishment is always immoral" or "Lying is never ethical." Claims about particular moral actions might be "Because of the circumstances of the case, Timothy McVeigh should be executed" or "Dr. Jones should not tell Ms. Smith that she is about to die."
Reservations are not part of claims about universal moral actions because these claims admit no exceptions. Claims of particular moral action, on the other hand, are frequently defined by the circumstances surrounding the actions contemplated. In these situations, arguments are designed to support exceptions to general moral principles because of the circumstances unique to the situation. A person generally opposed to capital punishment might argue, for instance, that McVeigh should be executed because of the especially heinous nature of his crimes. Or a person generally opposed to lying might argue that because of Ms. Smith's mental condition, Dr. Jones should not tell her that her disease is terminal.
The model of practical reasoning including reservations is illustrated as follows:
A Model of Practical Reasoning Using Reservations
Reservations are especially important to practical moral argument because they give people the tools to help liberate themselves from what Jonsen and Toulmin call "the tyranny of principles."(15) Unencumbered by statements relevant to individual circumstances, moral principles can be used in tyrannical ways. Moral principles designed to prohibit a person from keeping a secret, telling a lie, having an abortion, or committing suicide regardless of the specifics of the individual's circumstances are tyrannical because they take the responsibility for moral decision-making from the individual and attempt to place it on an assumed-to-be objective and separate moral principle.
These, then, are four elements involved in practical argument: starting points, warrants, claims, and reservations. These four elements and the relationships among them are not intended to replicate arguments as they exist in reality. The model merely includes a few of the features and relationships relevant to their place of reason in argument.
In addition, the model does not contain criteria for evaluating practical arguments. The mere absence or presence of these four element says virtually nothing about the cogency of an argument. To evaluate the reasoning contained in an argument, one must go beyond this model.
As noted earlier, the criteria for evaluating a formal, deductive logic are truth, validity, and soundness. For practical argument the criteria are similar, but different in subtle ways. These criteria are acceptability, relevance, and sufficiency.(16) Each of these criteria is necessary for a logically cogent argument; taken together these criteria are sufficient for a cogent argument.(17)
Premise Acceptability
The question asked in practical reasoning is not so much whether premises are true but whether they are acceptable to an audience. If a premise is acceptable to an audience, then it is one from which argument can begin. Evaluating the acceptability of premises is the primary means of evaluating the substantive dimension of an argument.(18)
The substitution of acceptability for truth is the way practical reasoning deals with the substantive dimensions of argumentation. The concept of premise acceptability (substituted for the logical concept of "truth of premises") provides means for dealing with problematic premises. If the premise or premises are acceptable to the audience, the argument can proceed. If premises are unacceptable, argument cannot proceed.
To be more precise, an argument can proceed when the premise is more or less acceptable to the audience. Unlike truth, acceptability is a concept which exists in the realm of the more or less. An audience need not completely accept nor completely reject a premise. The audience might accept a premise with varying degrees of force, believing a premise is possible, plausible, or probable.
For instance, consider the argument that "President Kennedy's murder was a conspiracy because Lee Harvey Oswald could not have accurately fired that many shots in the time available." The claim "President Kennedy's murder was a conspiracy" is based on the premise that "Oswald could not have accurately fired that many shots in the time available." An audience informed on the subject would realize that the premise is itself debatable. Their reaction might be that the odds are about fifty percent that Oswald could have fired three shots with the needed accuracy. For this audience the premise is neither absolutely true nor absolutely false. As a result, the audience's faith in the conclusion will be qualified as well. The audience probably will not believe the conclusion is either absolutely false or absolutely true; they will more likely believe that the conclusion is probable or improbable.
Relevance and Sufficiency
In addition to beginning with premises which are acceptable, a good argument uses premises which are relevant to the claim and sufficient to warrant our belief in the claim. Thus, the concepts of relevance and sufficiency deal not with the acceptability of the premises but with the connection between premise and conclusion. Relevance and sufficiency as they are used in practical argument are analogous to validity in formal logic.
Saying that the premise or premises upon which a good argument is based must be relevant to the conclusion seems so obvious as to be trivial. What exactly is a relevant premise? What are the criteria by which relevance is determined? Who is in the best position to decide if these criteria have been met?
Blair describes premise relevance in the following manner:
Asserting that a premise is relevant to a conclusion commits one to holding that accepting the premise should lead one to be either more inclined, or else less inclined, to accept the conclusion than one would be if one didn't accept the premise.(19)
Blair's definition of premise relevance contains an implicit criterion for deciding whether or not a premise is relevant to a claim. A premise is relevant to the claim if the belief in the premise affects an audience's belief in the claim. But Blair's language is decidedly more precise. He says that belief in a relevant premise ought to make the audience "either more inclined, or else less inclined" to believe in the conclusion. Notice that a belief in a relevant premise influences a belief in the conclusion but does not automatically guarantee our belief in it. For instance, a belief that Jack Ruby was an associate of the Mafia may make an audience more inclined to believe that the assassination of President Kennedy was a Mafia conspiracy, but that premise alone does not ensure their belief in the claim.
In addition to being relevant, a premise needs to be sufficient to establish a claim. The difference between relevance and sufficiency is one of degree. Belief in a relevant premise makes an audience more or less inclined to accept a claim but the belief in a sufficient premise directly leads to the acceptance of the claim. Said another way, a relevant claim can be insufficient but a sufficient claim cannot be irrelevant.
Sometimes a premise is relevant but still not sufficient. Two of the most common reasons premises fail to meet the test of sufficiency involve the care with which the premises were selected as well as the nature of the claim the premises were intended to support. Frequently a premise is insufficient because the evidence was gathered in a hasty or slipshod manner. Examples include polls based on unrepresentative samples or examples that ignore the existence of evidence to the contrary. These premises might still be relevant to the claim, but they are not sufficient to establish the claim.
A second reason that a premise might not be sufficient involves the fact that a premise might support only a portion of the claim it is intended to prove. To return to an earlier example, some people believe that the premise that Jack Ruby was an associate of the Mafia is sufficient reason to establish the claim that the JFK assassination was a Mafia conspiracy. The premise is certainly relevant to the claim, but it is insufficient. The claim that the JFK assassination was a Mafia conspiracy requires a causal connection between the Mafia and the assassination. The premise that Ruby is associated with the Mafia certainly provides a connection but not necessarily a causal one. The association between the Mafia and the assassination might be coincidental. The fact that a Mafia associate was a key player in the drama surrounding the assassination does not mean that the Mafia ordered the murder.
The criteria to evaluate practical argument presented here has as its key elements the concepts of acceptability, relevance, and sufficiency. These concepts do not describe the whole of human reason, but they are important to it. A system of argumentation adequate to tackle issues faced by people in their everyday lives must be able to deal with questions of substance as well as questions of inference. Acceptability is designed to evaluate the substance of an argument's premises as relevance and sufficiency are designed to evaluate the inferential elements of the argument.
This chapter has attempted to illustrate one view of the place of reason in argumentation. It claims neither to represent the whole of argumentation nor to represent it precisely as it occurs in real life. This model, like others, is only a representation of arguments; it is not the thing itself. Hopefully, the categories presented in this chapter will allow students of argumentation to go beyond the categories themselves in order to make arguments and evaluate arguments in unique and creative ways.
1. For one account of the reasons formal, deductive logic was considered the only respectable form of reason and rationality, see Stephen Toulmin, Cosmopolis: The Hidden Agenda of Modernity. New York: Free Press, 1990.
2. Stephen F. Barker, The Elements of Logic. McGraw-Hill, New York: 1965, p. 3.
4. Stephen Toulmin. Uses of Argument (Cambridge: Cambridge University Press, 1958).
5. This model is based primarily on the model developed by Albert R. Jonsen and Stephen Toulmin in The Abuse of Casuistry: A History of Moral Reasoning, p. 35. The description of the model in this text combines the ideas of Jonsen and Toulmin with those of Stephen Toulmin in Uses of Argument and of Chaim Perelman and Lucie Olbrechts-Tyteca in The New Rhetoric: A Treatise on Argumentation.
6. Charles Arthur Willard. "On the Utility of Descriptive Diagrams for the Analysis and Criticism of Arguments." Communication Monographs, 43 (November, 1976), 308-19.
7. Perelman and Olbrechts-Tyteca, p. 65.
9. Stephen Toulmin, Richard Rieke, and Allan Janik. An Introduction to Reasoning. (New York: Macmillian Publishing Company, 1979), p. 25.
10. Perelman and Olbrechts-Tyteca divided starting points into two categories: starting points relating to the real and starting points relating to the preferred.
11. Douglas Ehninger and Wayne Brockriede called this "real evidence." Decision By Debate. (New York: Dodd, Mead & Company, 1963), p. 110.
12. This and other examples in this section exclude the concept of reservations because reservations are not defined until the next section of this chapter.
13. The patterns referred to here as absence and presence are similar to the "Methods of Agreement and Difference" in John Stuart Mills, A System of Logic (London: 1843).
14. As noted, correlation does not prove causation, but the absence of correlation is sufficient to refute the existence of a causal relationship.
15. Toulmin and Jonsen, p. 5-11.
16. These concepts are, of course, not original. They are borrowed from University of Windsor Philosophers Ralph H. Johnson and J. Anthony Blair. Logical Self-Defense. New York: McGraw Hill Inc, 1994.
17. Ralph H. Johnson and J. Anthony Blair. Logical Self-Defense: Third Edition. (Toronto: McGraw-Hill Ryerson, 1993), p. 49.
18. I would remind the readers that conceptual audiences such as the "universal audience" and the "community of model interlocutors" are included in this notion of audience.
19. J. Anthony Blair. "Premise Relevance." in Robert Maier (Ed.) Norms in Argumentation: Proceedings of the Conference on Norms, 1988. Dordrecht, Holland: Foris Publications, 1989, p. 81.