This article discusses six lessons learned from teaching critical thinking. The lessons are: Critical thinking is hard; practice in critical-thinking skills themselves enhances skills; the transfer of skills must be practiced; some theoretical knowledge is required; diagramming arguements (argument mapping) promotes skill; students are prone to belief preservation.
Lesson 1: Critical Thiking Is Hard
Van Gelder cites author Deanna Kuhn who in her the book The Skills of Argument concludes that most most people cannot demonstrate basic skills in making arguments and reasoning. Gelder goes on to explain how humans never evolved to be critical thinkers. Critical thinking is a complicated skill that is built out of simpler skills. Gelder conlcudes lesson one by comparing the difficulty of critical thinking with the difficulty of learning second language.
Lesson 2: Practice Makes Perfect
Because critical thinking is a skill, it is not enough to learn about theories and concepts. Students must take part in activities with the intention of improving their critical thinking skills, and these activities along with feedback must be continuous.
Lesson 3: Practice For Transfer
The problem of transfering a skill to multiple diciplines is difficult in all fields. Gelder believes that critical thinking skills are especially susceptable to the problems of transfer because of its generalist nature. The solution according to Gelder is to teach transfer of critical thinking from one subject to another as a skill in critical thinking.
Lesson 4: Practical Theory
Gelder opens this lesson by discussing how if most beer drinkers knew more about the elements of what is in beer and how it is made, they would have more appreciation for beer. Similiar to greater appreciation of beer, someone who knows more about the theory of critical thinking is more likely to appreciate it. Gelder beleives that students do not receive enough instruction about theory in critical thinking, however, he does consider it a mistake to think that a student can develop critical thinking skills exclusively through the study of theory.
Lesson 5: Map It Out
Arguments are presented in spoken or written words. Evidence supporting an argument can be broken down into hierarchical structures. It is these structures that can be diagrammed. The more complicated the argument, the more useful a visual representation can be. Gelder backs this assertion from studies comparing students of critical thinking who used argument maps and those who did not. Students using visual argument maps showed greater improvement in crtitical thinking skills.
Lesson 6: Belief Preservation
Gelder discusses how cognitive bias and "blindspots" either from evolution or societal influence, "...corrupt our thinking and contaminate our beliefs." He likens awareness of these features as being as important to critical thinkers as adjusting aim for windage is for archers. According to Gelder belief preservation is the most prominent form of bias. People will lower the status of evidence in their minds if it contradicts their beliefs. A good critical thinker must be aware of these bias.