“Ehninger and Brockreide introduced debaters to the informal logical model of Stephen Toulmin, a British philosopher of science. Now almost every modern debate text uses the Toulmin Model as the method of teaching argument. Toulmin first explained this model in his 1958 book The Uses of Argument.
Toulmin argued that every argument (if it deserves to be called an argument) must consist of three elements: data, warrant, and claim.
The claim answers the question ‘What are you trying to get me to believe?’—it is the ending belief. Consider the following unit of proof: ‘Uninsured Americans are going without needed medical care because they are unable to afford it. Because access to health care is a basic right, the United States should establish a system of national health insurance.’ The claim in this argument is that “the United States should establish a system of national health insurance.”
Data (sometimes also called evidence) answers the question ‘What have we got to go on?’—it is the beginning belief. In the foregoing example of a unit of proof, the data is the statement that ‘uninsured Americans are going without needed medical care because they are unable to afford it.’ In the context of a debate round, a debater would be expected to offer statistics or an authoritative quotation to establish the trustworthiness of this data.
Warrant answers the question ‘How does that data lead to the claim?’—it is the connector between the beginning belief and the ending belief. In the unit of proof about health care, the warrant is the statement that ‘access to health care is a basic human right.’ A debater would be expected to offer some support for this warrant. Such support might come from the United Nations Universal Declaration of Human Rights, from the preamble to the U.S. Declaration of Independence, or by quoting a statement from a health care expert.
The most common argumentative inadequacy is the unwarranted claim—a debater merely makes a claim without attempting any type of support without attempting any type of support. Suppose a debater attacks the national health insurance proposal by declaring that ‘the cost of a national health insurance system would cause the U.S. deficit to skyrocket.’ This is a claim, but it is not an argument because there is neither data nor warrant.
Sometimes a debater will offer data and claim but omit the warrant. Suppose the debater reads evidence that the U.S deficit now stands at $8.9 trillion and then makes the claim that ‘the cost of a national health insurance system would cause the U.S. deficit to skyrocket.’ Now that statement has data and claim, but the warrant is mission—there is nothing connecting the current sizable U.S. deficit to a claim that national health insurance will make this deficit substantially worse. Accordingly, the statement does not meet the definition of an argument.
Occasionally, a debater will present data without offering either a warrant or a claim–the debater simply presents an ‘interesting fact.’ Suppose in our national health insurance debate, a student reads a piece of evidence showing that Hillary Clinton, when she was first lady, proposed national health insurance in 1994. This data may well be accurate, but it doesn’t lead anywhere. There is no argument unless the data is connected to a claim through a warrant.”
Excerpted from: Edwards, Richard E. PhD. Competitive Debate: The Official Guide. New York: Penguin, 2008.