1. The Toulmin Method: A Modern Variant of Formal Logic
EN101
The Toulmin Method: A Modern Variant of Formal Logic

2. Stephen Toulmin British philosopher and educator
Toulmin believed that for an argument to succeed, it needs to provide justification for a claim. This, he believed, will ensure it stands up to criticism and earns a favorable verdict.
According to the Toulmin model, a claim is linked to its support through what is called a warrant.
A claim’s warrant indicates how one gets from factual support (which Toulmin calls data) to the claim.

3. Defining Some Terms
Claim – is a sentence that asserts something that may be true or false and so needs support: The world is warming up. This is the best English class. Twinkies taste good.
Data or Reason – is a sentence supporting your claim, main or not. It is generally triggered by the word because: Twinkies taste good because they have cream filling.
Warrant – what connects or bridges the data to the reason. You might consider renaming this the “necessary assumption.”

4. An Argument
Brand A peanut butter has been proven to be healthier than Brand B. Furthermore, most children prefer the taste of Brand A to that of Brand B. Therefore, parents should choose Brand A over Brand B.
This seems like a fair argument on the surface. But is the person, who is claiming that peanut butter A is better than peanut B, assuming anything to reach his/her conclusion?

5. Sound Arguments as Buildings

6. Parents should choose products that are healthier and taste better.
Diagrammed
Therefore, parents should choose Brand A over Brand B.
Brand A peanut butter has been proven to be healthier
than Brand B.
Furthermore, most children prefer the taste
of Brand A to that of Brand B.
Parents should choose products that are healthier and taste better.

7. Revised Argument
Brand A peanut butter has been proven to be healthier than Brand B. Furthermore, most children prefer the taste of Brand A to that of Brand B. Parents should choose products that are healthier and taste better. Therefore, parents should choose Brand A over Brand B.

8. Another Argument
Environmentalist: When bacteria degrade household cleaning products, vapors that are toxic to humans are produced. Unfortunately, household cleaning products are often found in landfills. Thus, the common practice of converting landfills into public parks is damaging to human health.

9. The correct assumption?
Environmentalist: When bacteria degrade household cleaning products, vapors that are toxic to humans are produced.
Unfortunately, household cleaning products are often found in landfills. Thus, the common practice of converting landfills into public parks is damaging to human health.
In at least some landfills that have been converted into public parks there are bacteria that degrade household cleaning products.
Converting a landfill into a public park will cause no damage to human health unless toxic vapors are produced.
If a practice involves the exposure of humans to vapors from household cleaning products, then it causes at least some damage to human health.
When landfills are converted to public parks, measures could be taken that would prevent people using the parks from being exposed to toxic vapors.
If vapors toxic to humans are produced by the degradation of household cleaning products by bacteria in any landfill, then the health of at least some humans will suffer.

10. Diagrammed
Thus, the common practice of converting landfills into public parks is damaging to human health.
When bacteria degrade household cleaning products, vapors that are toxic to humans are produced.
Unfortunately, household cleaning products are often found in landfills.
In at least some landfills that have been converted into public parks there are bacteria that degrade household cleaning products.

11. A Diagrammed Example
A junior-year-abroad-program will help the department establish international connections. (Data)
My college major should start a junior-year-abroad program. (Claim)
International connections would be valuable to my college. (Warrant)

12. Another Diagrammed Example
While the team has potential, it lacks maturity and depth. (Data)
The Washington Wizards are not good enough to make the playoffs. (Claim)
Maturity and depth are required attributes of a playoff team. (Warrant)

13. Warrants At the moment, this is all we need to be concerned with.
So, the warrant or the necessary assumption is what connects the data to the claim.
Another way to remember the warrant is to picture:
But, more specifically, picture the following:
Data (Reason)
Claim
Warrant

14. In-class and next class
Finish the following warrant worksheet. Read the claims and data carefully. Don’t make unwarranted assumptions based on clichéd arguments or emotion. Reason well.
Essay 1 rough draft is due Monday, August 1.
Bring 2 hard copies of at least 1-2 double spaced pages.