Introduction

This is what is commonly called a “Critical Thinking” textbook, and is intended to be used as a resource in a semester-long course. The goal of this text is to help students reflectively enhance their general reasoning skills.  Before unpacking this goal, it is important to say something about how a course in Critical Thinking differs from the many courses students have already taken on the subject of reasoning.  Our society takes the reasoning skills of its citizens very seriously, and we expend vast resources teaching our children the quantitative reasoning skills that we generically refer to as ‘math’.  In kindergarten (if not before) we start with basic arithmetic, and over at least the next decade of their lives we move on to teach children fractions, ratios, exponents, algebra, geometry, and so forth.  What unifies these subjects is that they are largely focused on methods for determining precise numerical values (albeit in different contexts and/or situations).  Society’s commitment to learning these skills makes perfect sense: knowing how to manipulate and determine numerical values is crucial in the modern world, and most people wouldn’t learn these skills without instruction.

However, not all of our reasoning is quantitative.  Many of the conclusions we come to, and decisions we make, are not about numerical values.  Moreover, not all the information that we use to draw these conclusions and make these decisions is quantitative.  For example, consider a jury deliberation.  Each member of the jury is supposed to consider the evidence presented by the prosecution and defense to determine the guilt or innocence of the defendant.  Of course, quantitative information might be presented to the jury, but a lot of the information presented to the jury will not be quantitative.  For example, witness testimony requires the jurors to determine whether the witness is trustworthy, and to decide to what extent their testimony is relevant to the case at hand.  Moreover, the jury will need to weigh the competing explanations of the crime presented by the opposing attorneys, and think about the plausibility of alternative explanations.  Finally, of course, the jury will have to determine the defendant’s guilt or innocence using the non-quantitative standard of ‘beyond a reasonable doubt’.  More broadly, as we navigate the world we are constantly engaged in reasoning that is not primarily quantitative, and this is the kind of reasoning that we will focus on in this text.

Given this, let us return to the text’s goal of helping readers reflectively enhance their general reasoning skills.  What does this mean?  Let us start with the term reflectively enhance.  Quantitative reasoning does not come naturally to most people, and we need to be taught these skills through repeated and prolonged instruction.  In contrast, we seem to have natural aptitude for other kinds of everyday reasoning, and this makes it easy to take these skills for granted.  However, the fact that a skill comes naturally to us, doesn’t mean we cannot improve on it, and this is precisely the aim of this text. Just as systematically reflecting on the mechanics of running can help a person improve their natural ability to run, so too reflecting on reasoning can enhance our existing skills, and that’s what we’ll do here.

This brings us to the second part of this text’s goal: to reflectively enhance our general reasoning skills.  As we’ve seen, we will be focusing on non-quantitative reasoning skills.  In addition, we will be focused on skills that are general insofar as they are applicable in a wide array of different circumstances and situations.  Overall, I take our general reasoning skills to involve identifying, analyzing, creating, questioning, evaluating, and refining arguments.  Despite this generality, sharpening these skills can have dramatic effects on our thinking and decision-making by helping to limit the options we take seriously, identify irrelevant issues or poor sources, know what questions to ask, and to reject inadequate arguments offered for or against some course of action (to name just a few).

To these ends, the text features (i) an extensive unit that teaches students to spot and visually represent arguments in multiple ways, (ii) a careful explanation of the standards for argument evaluation, (iii) a detailed consideration of common argument types, along with common mistakes and the questions we need to ask to avoid making them.  In addition, a distinctive element of the text is its emphasis on the contexts in which we reason.  Specifically, this book emphasizes the social and psychological contexts for reasoning, and it important to say something about each of these contexts up front.

Let us start with the social context.  Although reasoning occurs within the private confines of individual minds, it is almost always a consequence of our interactions with other people.  This shouldn’t be surprising, after all, we are social animals.  We get a great deal of our information from other people, we regularly turn to other people to check our thinking, and we use what other people are saying or doing as a guide for our own lives. Given this, social factors play a significant role in what we know and what we do.  Social factors can be a good guide to the truth, but they can lead us astray in some cases, and knowing how social factors influence us can put us in a position to avoid or mitigate the influence of misleading factors.  The text emphasizes interpersonal influences on our thinking in a number of ways.  First, it places upfront a discussion of the importance of ‘cooperative dialogue’ and ‘cooperative disagreement’.  Second, the book includes a unit on ‘social arguments’ focusing in particular on the role of trust in thinking.  Third, the text emphasizes a variety of influences from the social psychology literature, from false consensus to fundamental attribution error and beyond.

This text also focuses on psychological context for reasoning.  Psychologists have been studying reasoning for decades, and they have discovered that we are subject to a variety of biases and cognitive illusions.  Just as we have to learn that the pencil in the glass of water is not really broken despite the way it looks, so too we need to learn that in some contexts arguments that look good—aren’t.  This is complicated by the fact that there seem to be different types of reasoning processes going on within us—from slow and consciously controlled thinking to semi-autonomous and completely autonomous processes.  A special focus on these factors comes in a discussion of dual-process theories in Unit #1, and bias and motivated reasoning in Unit #3.  The text is also focused on fostering the transfer of these skills from the classroom into students’ own thinking.  Thus, the text draws upon examples and exercises from a wide range of everyday situations in an effort to show the wide relevance and applicability of these ideas.  Finally, the text illustrates terms and concepts through conversation between named individuals to both encourage transfer, as well as highlight the social context for much of our thinking.

To put it briefly, then, this book aims to improve its readers’ reasoning by teaching the basics of argument identification and evaluation within the social and psychological contexts in which it normally occurs, and ultimately, to give readers’ the confidence to think through the challenging problems and decisions we all face.