Excerpt from R. Schwartz & D. Perkins (1989) Teaching Thinking-Issues and Approaches, Pacific Grove, CA: Midwest Publications (currently known as The Critical Thinking Co.™)
Content first, thinking later. The point is often and rightly made that thinking has to be thinking about something. Sometimes this is taken to mean that students are not ready to think about a field until they have acquired a considerable base of knowledge and fundamental techniques. For instance, some feel that students cannot write essays until they have a thorough understanding of punctuation and paragraph structure, or that they cannot do even elementary mathematical thinking until they have mastered the basic operations of arithmetic. Research shows that this is simply false. There are many opportunities to engage youngsters with limited writing skills in meaningful writing tasks, or with limited mastery of the operations of arithmetic in thoughtful explorations of matters mathematical. Indeed, we agree with the many who argue that postponing such activities contributes to lack of student interest, because the subject matter in question comes to seem a mere matter of rote knowledge and skills.
Thinking first, content later. This hazard is complementary to the above. Sometimes it's imagined that improvement in various kinds of thinking will set the stage for easy mastery of content. We can make students good mathematical problem solvers if only we teach them, in advance, some sound general principles of mathematical problem solving. Then, when we feed them the details of some new mathematical content, they will be equipped to understand those details readily and apply them fluently in solving problems. Unfortunately, this works no better than the "content first, thinking later" approach. Any new body of content requires time and care to assimilate. To be sure, a better thinking process will help in mastering new content, but it will not make the matter routine. One reason is that general ways of organizing one's thinking need to be adapted somewhat to new content; another is that new content usually brings with it the need for particular ways of organizing one's thinking not yet in the learner's repertoire.
Thinking and content learned together. When thinking and content are learned together, the thinking illuminates the content and vice versa. "Together" need not mean "in the very same course," although many of the most interesting current efforts to develop students' thinking do integrate the teaching of thinking with the teaching of subject matters. But at least it means that students are learning, in one place or another, ways of thinking appropriate to the content they are acquiring. For instance, they are learning ways of problem solving relevant to the level of math they are studying, communication skills relevant to their level of mastery, and strategies of critical thinking relevant to their work in history and social studies.
Thinking is a performance—something to be done. Sometimes approaches to developing students' thinking treat thinking as a subject matter, something to be learned about. For instance, in a course on critical thinking, students might learn about the structure of arguments, the fallacies commonly found in arguments, and the ways arguments contrast in different domains such as science, mathematics, and law. All of this is interesting and important: it may improve the critical thinking of some students. Unfortunately, for most students it will have no impact at all on their actual critical thinking. Students have learned about critical thinking but have made no effort to put precepts in practice. Instruction should avoid simplistic approaches such as segregating thinking from content or just teaching students about thinking without engaging them in thinking.