Writing Logic: Claim, Evidence, and Warrant

As with many of the fundamental aspects of writing, making a claim is something we do often in daily conversation. When John says that, “taking the bus to work is better for the environment than driving a car” he is making a claim. A claim is a statement that is used to assert a point or convince the audience or reader of a particular argument. A claim is inherently debatable, and therefore needs reasons or evidence to support it. For example, John might back up his claim by noting that, “more people riding the bus means less cars on the road, fewer emissions, and lower fuel consumption.” The partnership of claims and evidence makes up the essential structure of logic and argumentation.

The importance of formal logic and argumentation is not limited to academic papers or philosophical arguments. A robust understanding of claims and evidence is fundamental to any genre of quality writing. Even something as commonplace as a thoughtfully written birthday card will contain the interaction of claim and evidence. For example:

Claim: 

           Lisa has grown and accomplished a lot this year.

Evidence:

           Lisa graduated from college this spring with a 4.0 GPA.

Writing that contains strong claims that are backed with solid evidence will be persuasive and convincing. When Lisa reads her birthday card, she will be delightfully convinced of her own accomplishments. From birthday cards to personal statements, college essays, or academic papers, strong writing is done with purpose. Structuring your writing around claims and evidence can give you the clarity to bring that purpose to the reader.  

The glue that holds claim and evidence together is warrant. A warrant is the logical connection between the evidence and the claim. It explains why a certain piece of evidence accurately supports the particular claim being made. For example, the warrant that bridges John’s claim and evidence would be the idea that more car emissions and fuel consumption is worse for the environment.

Claim:

           Taking the bus to work is better for the environment than driving a car.

Evidence:

           More people riding the bus means less cars on the road and fewer emissions and fuel consumption.

Warrant:

           More car emissions and fuel consumption is worse for the environment.

Consider Lisa’s birthday card:

Claim:

           Lisa has accomplished a lot this year.

Evidence:

           Lisa graduated from college this spring with a 4.0 GPA.

Warrant:

           Graduating college with a 4.0 GPA is a huge accomplishment.

Warrant is something that we often take for granted or overlook entirely. It is a term that does not get thrown around in conversation as much as claim and evidence, and in some ways it is a harder concept to grasp. This is partly due to the fact that warrant can often go unstated. It can be an underlying assumption that is basic enough to be left alone. For example:

Claim:

           You should take an umbrella with you today.

Evidence:

           It is raining outside.

Warrant:

           An umbrella will protect you from the rain and keep you dry.

In this case, the warrant is so obvious that it does not need to be stated. However, more complex claims and evidence will need some backing and explanation of warrant. When you become immersed in the subject matter for an essay it can be easy to overlook logical connections that may be less obvious to your audience. It may be helpful to stop and ask yourself, “is the connection between this claim and evidence clear to the reader?”

A piece of evidence can be completely true, but without a proper warrant the evidence will lend no credence to the claim in question. Consider an alternative piece of evidence for John’s claim:

Claim:

           Taking the bus to work is better for the environment than driving a car.

Evidence:

           Taking the bus will save you the gas money you would spend on your car.

This evidence is not wrong, but there is no warrant connecting it to the claim. The claim is an environmental statement, whereas the evidence provided addresses a financial concern. It is tempting to focus only on the accuracy or validity of evidence, but without warrant the evidence is essentially meaningless and the claim is given no support.

When you sit down to begin brainstorming a piece of writing, it can be helpful to think in terms of claims, evidence, and warrant as building blocks. This can organize your thoughts into a structured pattern that will help you build a coherent argument and give your writing clarity and focus.