Toulmin Method

Toulmin Method

The Toulmin Method is an informal method of reasoning. Created by the British philospher Stephen Toulmin, It involves the data, claim, and warrant of an argument. These three parts of the argument are all necessary to support a good argument. The "Data" is the evidence used to prove something. The "Claim" is what you are proving with the data. The "Warrant" is the assumption or principle that connects the data to the claim. All three parts are necessary.

For an example: Harry was born in Bermuda, so Harry must be a British subject.

In the above sentence, the phrase "Harry was born in Bermuda" is the data. This is evidence to support the claim. The claim in sentence above is "Harry must be a British subject." The warrant is not explicitly stated in this sentence; it is implied. The warrant is something like this, "A man born in Bermuda will be a British subject." It is not necessary to state the warrant in a sentence. Usually, one explains the warrant in following sentences. Other times, like in the sentence above, the speaker of the sentence assumes the listener already knows the fact that all people born in Bermuda are British subjects.

Another example: Steve bought apple juice for himself, so he must like apple juice."

This argument provides the data, claim, and warrant. The data would be the fact that Steve bought apple juice for himself. The claim is that Steve must like apple juice. The warrant is that people who buy apple juice, drink it, which means that they must like it, or else they wouldn't drink it. Again, the warrant is considered background knowledge and unnecessary to repeat in the argument. If one were to expound this argument, however, it would be helpful to explain the warrant.

An author usually won't bother to explain the warrant because it is too obvious. It is usually an assumption or a generalization. However, the author must make sure the warrant is clear because the reader must understand the author's assumptions and why the author assumes these opinions. An example of an argument with an unclear warrant is like this: "Drug abuse is a serious problem in the United States. Therefore, the United States must help destroy drug production in Latin America." This may leave the reader confused. By inserting the warrant in between the data and the claim, though, would make the argument clearer. Something like, "As long drugs are manufactured in Latin America, they will be smuggled into the United States, and drug abuse will continue." This phrase makes clear why the evidence relates to the claim. One must be cautious as to deciding whether or not to include the warrant in the argument because flaws in the argument could be obvious.

The Toulmin method is also helpful in identifying and creating persuasive arguments. When a writer lays out the Data, Claim, and Warrant of an argument, it can make writing an argument much easier.

Reference: "Reasoning." The Bedford Reader. By X.J. Kennedy, Dorothy M. Kennedy, and Jane E. Aaron. Ed. Denise B. Wydra and Karen S. Henry. 9th ed. New York: Bedford/St. Martin's, 2006. p.519-522.