Analyzing Assumptions

You will note how the Toulmin model gives expression to the usually unspoken but necessary assumption. The Toulmin model shows us that assumptions are the link between a claim and the evidence used to support it. And, really, we should say “assumptions” here, because arguments of any complexity are always based on multiple assumptions. If your audience shares those assumptions, it is more likely to agree with the claim, finding the argument to be sound; if your audience does not, then the assumption becomes yet another claim requiring evidence. And if you were asked to analyze an argument in order to determine whether you support or challenge its claim, finding vulnerabilities in the assumptions would be the place to begin.

Let’s take a look at how assumptions can become arguable claims by revisiting a piece that you read earlier in this chapter, Amy Domini’s article “Why Investing in Fast Food May Be a Good Thing.” We will see that by using the Toulmin method you could paraphrase her argument as follows:

Because the fast food industry continues to grow and is not going away, therefore even those of us who support Slow Food should invest in it, since investing has the power to persuade businesses to change.

The last part expresses one of the assumptions the audience must agree on in order for Domini’s argument to be persuasive. Does investing have the power to persuade business to change?

Two examples from the education article by Fareed Zakaria will further illustrate the method. Paraphrased according to Toulmin, one of Zakaria’s arguments would run as follows:

Because Chinese and South Korean children spend almost two years more in school than do Americans, therefore they outperform Americans on tests, since increased instructional time is responsible for increased test scores.

Do you agree with the assumption that increased instructional time is responsible for increased test scores? Alternatively, revealing another assumption, one might say:

Because foreign students spend more time in school and achieve higher test scores, therefore they receive a better education, since quality of education and learning is indicated by test scores, on account of their accuracy in assessing learning.

Again, the assumption here might very well be debatable. Is learning indicated by test scores?

Sometimes, in the development of an argument, claims are presented implicitly early in the piece and more explicitly later. For an example, let’s return to “The C Word in the Hallways” by Anna Quindlen. In the article, she makes several claims and supports them with credible evidence. Still, if you are to agree with her position, it is necessary to agree with the assumptions on which her arguments rest. Using the Toulmin model can help you to discover what they are, especially when the claim is implicit, as in the following:

So many have already been lost. This month Kip Kinkel was sentenced to life in prison in Oregon for the murders of his parents and a shooting rampage at his high school that killed two students. A psychiatrist who specializes in the care of adolescents testified that Kinkel, now 17, had been hearing voices since he was 12. Sam Manzie is also 17. He is serving a 70-year sentence for luring an 11-year-old boy named Eddie Werner into his New Jersey home and strangling him with the cord of an alarm clock because his Sega Genesis was out of reach. Manzie had his first psychological evaluation in the first grade.

Using the Toulmin model, Quindlen’s implicit argument here might be paraphrased as follows:

Because Kinkel’s and Manzie’s mental illnesses were known for several years before they committed murder, therefore mental health care could have saved lives, since psychological intervention would have prevented them from committing these heinous acts.

As you finish the article, you come to realize that the entire argument rests on that assumption. Indeed, would psychological intervention have had that result? It certainly provokes discussion, which means that it is perhaps a point of vulnerability in Quindlen’s argument.