Introduction
Toulmin's scheme may seem complex--too many concepts, too many terms--but it is a powerfully creative and critical tool. My experience has been that a student's writing improves when he/she commits himself/herself to understanding and using Toulmin's scheme. Such students begin to use evidence effectively, and they write papers with greater sensitivity to audience. Toulmin's scheme holds students accountable for every part of their arguments, forcing them to question the foundations (assumptions) that underlie their claims.
Although Toulmin's scheme may be difficult initially, the effort it takes to learn it will be beneficial to you in the future. Think: you work hard in other courses to learn complex systems--accounting, biology, calculus, physics--and each of those disciplines has a terminology and a taxonomy that requires time to learn. Hence, my enthymeme: if you work hard to learn difficult material in other courses, then you can work hard to learn Toulmin's scheme.
Explanation and Example
What is an enthymeme? An enthymeme is a claim with grounds. A claim is an assertion (a declaration or a statement) open to question. In an argument a person states his/her position in the form of a claim, which functions as the thesis of the argument. In other words, a claim is an answer to a topical question. An example of a topical question is: who will be our next chairperson? A relevant claim: we must not choose Stephen as our chairperson. Grounds (reasons and evidence) support a claim. Words such as because, thus, since, consequently and therefore underscore the logical connection between claims and grounds. To expand the aforementioned example into a framework for an argument: we must not choose Stephen as our next chairperson because he is too bossy. It is better to list multiple reasons and/or evidence in order to make your argument stronger and to divide your persuasive task into a series of more manageable tasks. Thus, some other reasons: he is mean, lazy, dumb, et cetera. I may select several of the traits (reasons) or all of them, depending on which will persuade my audience. Each line of reasoning needs a distinct section in my argument. Furthermore, I must provide evidence that he is bossy (et cetera), asking those who work with him to offer testimony about his bossiness (et cetera). In other words, certain evidence must support each reason.
To render my enthymeme logically complete--that is, to begin to build an effective argument--I must provide an assumption (a warrant)--a general, hypothetical statement--linking the claim with the grounds. An example of a warrant: bossy people are bad committee chairs. Because a warrant is also debatable (is also a claim), I must provide backing--justifications (moral principles, testimony of experts, references to texts, or empirical justifications) for the statement. Thus, I need to explain that bossy people tend to bring out the worst, rather than the best, in those around them; that bossy people tend not to ask advice; that bossy people make bad decisions; et cetera.
Stephen may have some supporters on the committee, so I must prepare for possible rebuttals of grounds (counterevidence of his cooperativeness and kindness, for examples) and/or backing (counterevidence of the necessity of a bossy person who can make decisions, for example). After I address such rebuttals, I must qualify my claim, depending on its strength. Words and phrases such as few, rarely, some, sometimes, in some cases, often, it is possible, perhaps, possibly, et cetera make claims more precise and honest. With respect to my argument, I will qualify my warrant (claim) as follows. In most circumstances bossy people are bad committee chairs.
Remember: you must rhetorically appeal to your audience--to inform them, to persuade them, and/or to motivate them. Your argument needs to be logical, emotional and ethical.
Advice
Initially formulating a list of grounds will break your argumentative task into a series of more manageable subtasks. The framework (working thesis) of an argument consists of a claim and at least one reason. However, a sequence of reasons and/or evidence will make your working thesis more informative, persuasive and/or motivational. Remember, though, that each line of reasoning will need a distinct section in an argument.
A warrant is an assumption (often regularly evident in essays but not in speeches) that links a claim with grounds. A warrant is a principle, value or belief an audience shares with you, guaranteeing the soundness of your argument. Although an audience may agree with your warrant, you must provide backing--specific information that supports your grounds, each item in your sequence of reasons and/or evidence. There are some general principles for the persuasive use of data. I suggest you apply the STAR criteria to your data: sufficiency (Is there enough evidence?), typicality (Are the data representative and typical--that is, not extreme?), accuracy (Are the data accurate and current?), and relevance (Are the data relevant to the claim?). Writers and speakers have numerous options for the kinds of evidence they can use in an argument: data from personal experience; data from interviews, questionnaires and/or surveys; data from research; statistical data; and hypothetical examples, cases and/or scenarios. Each kind of evidence has strengths and weaknesses.
Before you present an argument to an audience, you must consider how your audience may refute it. An adversarial audience may challenge your grounds, backing or both. After such considerations, you must qualify your claim to limit its force and to indicate the degree of its probable truth. When you qualify your claim, you transform it from a working thesis into a thesis. The qualifier will remind you that real-world arguments almost never completely prove a claim. Add words such as likely and probably to modify the strength of your claim.
