One of the central notions of any type of dialogue is commitment. As arguers in a dialogue make various claims and put forward arguments or make moves of any kind, these moves incur commitments for them. For example, if an arguer agrees to the proposition that tipping leads to bad consequences, she becomes committed to that proposition. Each partici- pant in a dialogue has a commitment set, sometimes called a commitment store, in which all the commitments of each participant are recorded. When a participant incurs a commitment, it is inserted into her commit- ment set. Thus each commitment is stored in a kind of data base containing a list of propositions that a participant in the dialogue has gone on record as accepting. Ideally, such commitments are kept track of in a data base. In real life, participants often forget their commitments or sometimes even try to hide them. Sometimes people will argue about them. For example, one person might say that another person once maintained that capital punishment is justified, while he (the second person) might insist that he never said that. Since there is no public record of what he said or didn’t say, there is no way of checking. However, ideally, in a dialogue, there should be a record of the previous moves in the dialogue and a record of the commitments of both parties.
When a participant in a dialogue has committed herself to a certain proposition then she is bound to acceptance of that proposition if the issue arises again later in the dialogue. Let’s take an example from the dispute on tipping. Suppose Helen has, previously in the dialogue, agreed to the proposition that any practice that rewards excellence of service is a good practice. And suppose that, at some other point in the dialogue, she agreed to the proposition that tipping rewards excellence of service.
Then it would be appropriate for Bob to use the following argument in the dialogue on tipping.
Any practice that rewards excellence of service is a good practice. Tipping rewards excellence of service.
Therefore, tipping is a good practice.
Bob points out, let’s say, that this argument is deductively valid and that Helen is committed to both premises. Because the structure of the argu- ment is valid, once Bob has pointed out that Helen is committed to the premises, she also has to accept the conclusion of this argument as a commitment of hers. What is shown here is that once you are committed to some propositions in a dialogue, you may also be committed to oth- ers, even if you did not realize it. You may become committed to other propositions that follow logically from ones you previously accepted as true.
One can certainly see why Helen should have to accept the proposi- tion ‘Tipping is a good practice’ as a commitment of hers once Bob has put forward the argument above. If she denies this proposition is true, she has been shown to be inconsistent in her commitments. And as shown in chapter 1, section1, inconsistency is a very bad thing in logic. If you contradict yourself, then everything you have said cannot be true. Incon- sistency is an important sign of error in critical argumentation. As things stand, Bob has shown that Helen has inconsistent commitments in the dialogue on tipping. Thus, Helen has to respond somehow and deal with Bob’s criticism.
When Bob used the argument above, however, it posed another prob- lem for Helen in the dialogue on tipping. Acceptance of the conclusion would mean that she has conceded that Bob is right that tipping is a good practice. But in the dialogue, she does not agree with that proposition at all. She is against it. Indeed, if she were to accept it, such a commit- ment would mean that she has lost the critical discussion on tipping. This concession would mean that in the dialogue, Bob has been successful in proving his thesis. So Helen is in a pickle here, unless she can retract her commitment to one of the premises. Should she be allowed to do this? The answer is that in a persuasion dialogue, it should be allowed. Helen can do it by explaining why she changed her mind. Suppose, for example, she decides to retract her commitment to the proposition that tipping rewards excellence of service, saying, “That’s not really right, and although it looked right at first, I now think it is wrong and I reject it.”
2. Commitment in Dialogue 181
Helen might even give some reasons why she thinks this proposition is not true. This kind of move seems generally very reasonable in a persuasion dialogue. In such a dialogue, when confronted by a rational argument that is logically reasonable and persuasive, you are supposed to accept the conclusion, even if you previously did not accept it. Retraction of this sort is part of being open-minded in a persuasion dialogue. You have to be open to new evidence and to changing your mind if your previous position was shown to be wrong. Thus, retraction of commitment should sometimes be allowed in a persuasion dialogue.
The central technical problem in formal models of persuasion dia- logue is to define the precise conditions under which retraction should be allowed. This is not an easy problem, and we shall not try to solve it here. Suffice it to say that there can be different kinds of persuasion dialogue, some with stricter rules, including rules of retraction, and some with more permissive rules. There are three general requirements on commitment in dialogue that can be stated, however, and that participants should be held to.
Three General Requirements on Commitment in Dialogue
1. If a proponent is committed to a set of statements, and the respondent can show that another statement follows logically as a conclusion from that set, then the respondent is committed to that conclusion.
2. The respondent has the right to retract commitment to that conclu- sion, but she must also retract commitment to at least one of the premises. For otherwise it has been shown that she has inconsistent commitments.
3. If one party in a dialogue can show that the other party has inconsis- tent commitments, then the second party must retract at least one of those commitments.
As shown in chapter1, inconsistency is generally a bad thing in logic. If a set of statements is inconsistent, they cannot all be true. At least one must be false. Thus if an arguer tries to maintain a set of commitments that is inconsistent, it means that there is something not right in her posi- tion. Thus the other party can use such a finding of inconsistency as a criticism.
Indeed, in chapter 3, section7, the argumentation scheme for Argu- ment from Inconsistent Commitment was presented. It is a negative form of argument from commitment. When confronted with such an argument,
a respondent must reply by dealing with the criticism. But it is possible for him to do this without losing the dialogue just because an inconsis- tency has been found in his commitment set. He can go further into the details of the case, and he may be able to show why the inconsistency is only apparent and not real. In some cases, it can look as if an arguer’s position is inconsistent, but further clarification may show that there is not really an inconsistency there or that it can be dealt with by mak- ing some corrections. If an argument has been going on for quite a few moves, a party’s viewpoint in the dialogue may consist of many single commitments, and the logical relationships among these commitments can be quite complex. Also, in realistic everyday argumentation, it can be quite hard or even impossible to keep an exact record of all an arguer’s commitments she incurred in the past. Thus as a matter of general pol- icy, commitment sets do not always have to be consistent. However, if one party in a dialogue points out correctly that the other party’s com- mitments are inconsistent, the party accused of inconsistency has to deal with this criticism at her next move.
To give another illustration of how these rules concerning commit- ment work, let’s go back once again to the dialogue on tipping. Suppose Helen gets Bob to agree that tipping has bad consequences in at least some cases, citing the time a waiter spilled soup on her husband’s suit, because there was a misunderstanding over tipping. In the chapter on argumentation schemes, it was shown that the following form of argu- ment is reasonable.
ARGUMENTATION SCHEME FOR ARGUMENT FROM NEGATIVE CONSEQUENCES
PREMISE: If A is brought about, bad consequences will plausibly occur.
CONCLUSION: A should not be brought about.
Since Bob has agreed that tipping has bad consequences, it follows from this form of argument that he is also committed to the conclusion that tipping should not be brought about. In other words, he is committed to the statement that tipping is the sort of practice that should not be continued. His commitments imply that it is a bad practice of a kind that ought to be stopped. But this commitment is inconsistent with Bob’s point of view in the dialogue. He is pro-tipping. In other words, he is committed to the proposition that tipping is a good practice of a kind that should be continued. So Bob is now in a pickle of the same kind that Helen was