Working With Assumptions

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Much of our research and writing involves crafting and analyzing complex arguments. It’s a real skill to be able to pick out logical errors or hidden assumptions. On this page we’ll teach you how to split every argument into its components parts.

Claim, Evidence, Warrant

The classic approach to dissecting arguments was developed by the British philosopher Stephen Toulmin. It’s called the Toulmin Method. For our purposes, we’ll focus on three key aspects of any argument:

  1. The Claim (or conclusion): a statement of a point you want to argue.
  2. The Evidence (or facts, reasons, grounds): the points that back up your claim.
  3. The Warrant (or assumption): the logic that ties together the claim and the evidence.

The warrant is probably the trickiest part. Think of it as a general assumption that often remains implicit and is not spelled out.

Let’s look at an example:

Claim: Bullying is a massive problem at our school.

Evidence: For one thing, the walls at the back of the school are sprayed full of graffiti.

Warrant: Graffiti is a sign of bullying.

In this case we’ve assumed that bullying and graffiti are somehow connected. The supposed link is spelled out in the warrant. Often, of course, the warrant is not really warranted and is something we can contest.

Here’s another example:

Claim: Our school should really have a pub.

Evidence: How can students be expected to be creative without having a beer or two?

Warrant: When students drink beer in a pub they will be more creative in school.

Again, the assumption is suspect. When we engage in debate or analyze other people’s arguments, it’s critical to drill down to the level of the warrant. Otherwise you’ll never get to the core of the issue.

Let’s finish with one more example–this time with two possible warrants:

Claim: Very few French people use bicycles to commute to work.

Evidence: French people tend to associate riding a bike with racing (e.g., in the Tour de France).

Specific warrant: When people associate biking with sport they are not likely to use bikes as a regular means of transportation.

Abstract warrant: A prejudice about a habit may limit adaptation to new circumstances.

You can see that one warrant may lead to another warrants. After all, our ideas are often based on a complex network of assumptions.

Audience Assumptions

Different readers make different assumptions. For instance, if you’re writing for a secular audience, it does not make sense to rely exclusively on the authority of a religious text. Consider the following argument:

We should all be willing to forgive our enemies. After all, the Bible tells us to turn the other cheek.

Implied is the idea that everyone should listen to the Bible. It would be more effective to rephrase the argument and indicate that the biblical reference is not to be interpreted as evidence but as an illustration of what the claim entails:

We should all be willing to forgive our enemies. As Jesus says, “Love your enemies and pray for those who persecute you.”

Such a revision makes the passage more neutral, though one might still have to add more proof to convince a secular audience that forgiveness is indeed a good thing.

In short, always consider whether the warrants implicit in your arguments will be shared by your audience.

More Information

To learn more about working with claims, evidence, and warrants, we recommend checking out The Craft of Research, 4th ed. (by Wayne C. Booth, Gregory G. Colomb, and others), an excellent introduction to the art of academic writing.