Critical Thinking: Formal and Informal Reasoning

Critical Thinking provides an easily understood and intuitive language argument presentation and regimentation, inductive logic, natural language fallacies, syllogistic logic, truth tables, and proof theory. Although each of these topics is standard in introductory logic and critical thinking textbooks, the authors’ friendly and encouraging writing style sets this book apart from others. Their style, while approachable, effectively communicates to students the necessity of organized and structured thinking and writing, and does so in such a gentle manner that students will probably not realize just how much they’ve learned until years after the fact, when they read something that will prompt a memory of a fallacy or an argument form first learned here. In writing a critical thinking/introductory logic text, one must decide what to introduce initially. One can, for instance, begin by diving right into natural language arguments, trying to tease the argumentative structure out of the welter of superfluous information and poor reasoning with which natural language arguments typically come packaged. While such a pedagogical method respects the student’s starting point, the risk of overwhelming the student with too much analytic machinery in the attempt to uncover logical structure is always a risk. One can instead start from the beginning—language and its constituents, words, and letters—and build words out of letters, sentences out of words, strings of sentences out of individual sentences, and arguments out of strings of sentences, pointing out along the way the logical structure implied at each step. This can be an effective pedagogical method, but it risks boring the students to tears in the first weeks of a course. The authors of this book work differently, starting with building arguments out of sentences, assuming their students’ informal familiarity with the structure of ordinary language and using it to expose the logical skeleton lying underneath the camouflaging layers of writing style and rhetorical flourish. Having introduced the fundamental connectives ‘not’, ‘and’, ‘or’, ‘if-then’, and ‘if and only if ’, the authors then introduce students to deductive and inductive arguments and the different standards that govern each. Only then do they turn to natural language fallacies, syllogistic logic, and sentential logic, all of which are covered carefully and with ingenuity. Their approach has the benefit of grabbing students’ attention early in the course and impressing on them that logic is rigorous. But it has the additional benefit of showing that validity and invalidity lie at the core of what makes a natural language fallacy a fallacy, thereby avoiding the appearance that they are nothing more than pettifogging word games. So, read and enjoy this book and learn from it. What it contains will sometimes be learned easily, sometimes only after some struggle. However, once learned, the cognitive benefits will last a lifetime.