Teaching Warrants to Help Students Think Critically about Claims and Evidence

by Ted Kinnaman, Chair, Philosophy

In academic studies of critical thinking, much attention is given to the notion of a warrant. Teaching students to understand the use of warrants in writing, no matter what the field, is important for helping them to assess the evidence for the claims they make, and for the claims by others that they study. When someone makes a claim or assertion, we can ask them, ‘how did you get there?’ or ‘why do you believe this?’ To cite a warrant is to answer this sort of question. It is to offer some justification for the claim just made. But there are many different sorts of claims and many sorts of warrant as well. Here are some of the most important examples:

Empirical claims:

Empirical claims are claims about how things are in the world (for example, that it is raining in Tennessee) and the warrant for such a claim must be evidence about the world. This might be an observation (I was just in Tennessee and saw it raining), a report of an observation (I talked to my parents in Nashville who said that it is raining), or a reference to a regular connection among phenomena (There is a low pressure area over the Southeast and that always causes rain in Tennessee).

Scientific claims:

Strictly speaking, scientific claims are empirical claims, but they are distinguished from ordinary empirical claims by the method by which they are supported. The warrant for a scientific claim is grounded in the scientific method: Why do you believe that smoking causes cancer? Because this hypothesis has been carefully tested, the results formulated to stay strictly within what the experiment supports, the conclusions confirmed through testing by other researchers, and so on.

Moral claims:

Claims about what is right or wrong are generally supported by appealing to broader moral principles that have the particular claim as consequences. For example, why do you think that the decision to drop the atomic bomb on Hiroshima was immoral? Because the bombing killed innocent people for no good overriding purpose, and killing innocent people needlessly is always wrong. Note that in addition to the moral principle, moral claims are often based in part on empirical claims with which one can take issue as outlined above.

Historical claims:

Claims about historical events require special sorts of warrants, citing evidence from historical sources. Specifically, historical knowledge usually depends heavily on testimonial evidence, such as contemporary accounts of events and official records or archives, as well as reasoned interpretation of such testimony by other historians. Why do you think that the harsh terms of the Treaty of Versailles led to the rise of Hitler? Because examination of German responses to Versailles show their direct linkage to the rise of virulent nationalism in Germany in the 1920’s.

Pragmatic claims:

The warrant for a claim about how to accomplish a goal depends on knowing how things work in the world. You should take the Metro to your interview in DC instead of driving, because all the highways into the city are crowded at that hour, and furthermore the stress of driving will cause you to have difficulty focusing on the interview.

Aesthetic claims:

Sometimes claims about beauty or artistic merit can be support by appealing to feelings (‘I love it!’) but more often they are supported by appealing to criteria for success in a particular area (Matisse’s The Dance is a great painting because of the perfect balance in the composition) or to a general principle about art or beauty (Citizen Kane is a great film because it makes the viewer care deeply about the fate of Charles Foster Kane).

Of course, there are other possible categories, and the lines between the categories are not as neat as presented here. But this is a valuable exercise for students writing in all disciplines. When students understand the concept of a warrant they are better able to make reasoned judgments about whatever material they study, and express these judgments in their written work.