April 9, 2012
The challenge for critical thinking instruction lies not in convincing people of its value but in developing a model of what to teach and how to teach it. Toulmin's model provides a useful framework for students to examine the ability of an argument to justify rather than prove a point. Utilizing this model can make critical thinking the very means by which students construct knowledge.
Debating, questioning, analyzing, searching for evidence-all of these skills have been attributed to the label critical thinking. But what exactly do these skills have in common, and how do we go about teaching them? All of these practices draw on both general knowledge about the structure of argument and specific knowledge about the topic at hand. They combine the skills of justification, use of evidence, and critical questioning. And they all require the dispositions of skepticism, inquiry, and impartial judgment. Teaching this constellation of knowledge, skills, and dispositions requires a methodical and cumulative approach that seems daunting in light of the resources and methods currently available to educators. But there are many complex skills in the school curriculum that take years of instruction for mastery-reading comprehension, expository writing, and mathematical problem solving, to name a few. And while we might debate our success in teaching such skills in high school, no one doubts that they can and should be taught. The challenge for critical thinking instruction lies not in convincing people of its value but in developing a model of what to teach and how to teach it. The absence of such a model is obvious when we look at examples of typical lessons. All too often critical thinking is taught in isolated language arts or social studies lessons that fail to connect to the larger curriculum. In such lessons students may learn about persuasive messages, argument fallacies, or even problem-solving skills. But these lessons generally occur with little or no reference to the course content, and they are rarely reinforced in subsequent lessons. As a result teachers find them ineffective and frustrating distractions from the curriculum. The problem is that these lessons are add-ons to the curriculum. If we are to treat critical thinking as the complex skill set that it is, it must be embedded in the curriculum and connected to a comprehensive set of goals and outcomes. One sensible strategy for developing a model for critical thinking instruction is to explore advances made in the field of argumentation. While there are dozens of ways to define critical thinking, most definitions include the ability to examine claims, conclusions, and assumptions. And while critical thinking may include much more, we can say with certainty that it at least involves engaging in a process of critically questioning arguments. Therefore, to build a model of critical thinking instruction we might begin with our understanding of the simplest unit of analysis-the argument. What we find is that argumentation theory itself has undergone significant changes in the past 50 years. And while many of these theoretical developments have found their way into critical thinking lessons, the aim here is to present a list of recommendations for high school teachers interested in revising their approach to critical thinking instruction. Focus instruction on informal, or inconclusive, arguments All too often teachers looking for lessons on critical thinking turn to formal logic for content. The allure is clear-formal logic offers a means of distinguishing conclusive from inconclusive arguments, allowing students to judge whether the conclusion of an argument is certain. Until recently, formal logic was the most common framework for developing critical thinking instruction. High school lessons in formal logic generally begin with syllogisms like the following: "All of Mary's brothers have