In the preface to Critical Thinking, Jonathan Haber notes that the term critical thinking has become a hallmark of almost any set of educational goals set out in the past thirty years. Yet, the myriad politicians, policy makers, indus-try leaders, and educators who cite the importance of critical thinking as an essential twenty-first-century skill rarely offer a concrete definition or set of criteria for what mastering this all-important skill means. Individual state standards or standards that do detail what is meant by critical thinking are rarely read by the general public. Even teachers may only view the standards amid a litany of other standards and skills that must be imparted to students. Haber sets out to fill this gap for a generalist audience. As such, Critical Thinking fits well among other volumes in MIT Press’s Essential Knowledge Series, a collection of volumes that cover specialized topics from a range of disciplines in a nuanced manner suitable for a nonspecialized audience. This orientation is crucial for understanding its strengths and weaknesses as a book that seeks to provide an overview of the history of, the skills required for, and current pedagogical efforts toward developing critical thinking.

Haber begins with the Greek philosophers and moves through the Enlightenment and up to today. Of note for educators is the fact that even in ancient Greece, the skill of critical thinking was not designated as a specialty of philosophers but as a core component of the curriculum of the time. The common thread tying together the various people and movements Haber highlights is their focus on eschewing adherence to traditional understandings or accepted explanations for physical, social, and psychological phenomena and, instead, their willingness to examine and question underlying assumptions that support contemporary dogma. In many ways, this history lesson provides the clearest picture of what Haber means by “critical thinking” throughout the book: a willingness to continually reexamine one’s own beliefs and to engage in that same generous skepticism with others.

The second chapter is perhaps the most technical in the book, as it focuses primarily on introducing the building blocks of formal logic. Although not written directly as a resource for lesson planning, this chapter outlines a number of the concepts that are easily adaptable to units focused on building skills for critical thinking. Haber shows how diagramming an argument in terms of premises and conclusions can help students of all ages understand its structure. Similarly, drawing the distinction between the validity of an argument (Does the form of the argument align with valid logical principles?) and its soundness (Do the premises correspond to reality? or How likely are they to be disproven?) can provide insight into where an argument is weak or how to anticipate attacks against an argument. Beyond this crash course in introductory logic, Haber also highlights other skills that are important for critical thinking, namely language skills, information literacy, and creativity, as well as dispositions that are essential for critical thinkers, such as intellectual humility, intellectual courage, and fair-mindedness.

In the third and final substantive chapter, Haber outlines current approaches to teaching and measuring critical thinking in the US education system. Here Haber notes that the modern movement around explicitly teaching critical thinking can be traced to a 1983 requirement that all students graduating from California state colleges and universities complete a course on critical thinking. Following this, policy makers and curriculum developers have striven to include critical thinking in many of the standards that have been put forth, most notably the Common Core State Standards. In all, Haber highlights how the messaging and expectations around critical thinking instruction have been growing at almost every level of education and argues that this is a welcome trend. At the same time, he points out how the actual implementation of instruction in this area has been uneven and often lags behind the aspirational rhetoric of educational leaders. He makes a convincing case that the process of becoming a critical thinker and honing critical thinking skills is one that should be lifelong and that, in many ways, the best instruction for developing critical thinkers is consistent practice in applying those skills, both as explicit portions of curricula and implicitly throughout other content areas.

In Critical Thinking, Haber illustrates a portrait of a critical thinker that is rather comprehensive. In his telling, critical thinking is not a skill to be applied to specific situations or circumstances but a stance that one has toward almost all subjects and encounters. In many ways, this portrait is compelling. Haber argues that if students and adults approach political, social, and scientific questions with the tools, skills, and virtues outlined in the book, it is likely that US society will focus on how to deal with difficult problems like climate change or systemic racism rather than debating whether these problems exist. He also grapples with alternatives to the paradigm of critical thinking, most notably proponents of group or team thinking who assert that thinking must be conceived of as a social act, compared to the more individualistic endeavor of critical thinking. Haber further points out that there is room for emotion in the critical thinking framework, noting that “by balancing our emotional, intuitive, and reasoning selves, we avoid cutting ourselves off from valuable data required to apply reasoning effectively in a world made up of people rather than machines” (p. 147).

Yet, the book would have benefited from a slightly more nuanced look into the limitations of critical thinking as Haber describes it. Specifically, what questions or types of questions will this approach find difficult or impossible to resolve? While Haber makes a convincing case that applying critical thinking principles to scientific questions should lead us to continually refine our understanding of the world, it is not clear how these tools can be applied to more nebulous political or moral questions where there may be no objective truth. Certainly, thinking critically about one’s own or an opponent’s political and moral arguments can lead to greater understanding, but it is not clear that such understanding will lead to agreement or resolution.

While the rules for building arguments are clearly laid out in this book, the criteria for selecting their foundations are less obvious. While not everyone will work from the same set of basic premises or values, these starting points are critical for understanding the conclusions that people reach. Nor do the tenets of formal logic offer a clear way to engage with these most fundamental beliefs. Critical thinking can help two people analyze each other’s points of view, but it does not help adjudicate between different starting premises, such as the existence of God or even the appropriate role of government in people’s lives. While it is not necessary for Haber to resolve these tensions, an exploration into or an acknowledgment of these limitations would have been helpful for readers of all levels of expertise as they consider ways to incorporate critical thinking skills into their instruction, policy, or daily lives.

Critical Thinking does succeed in providing a thorough yet high-level introduction to historical and modern thought on the topic. Given the current diversity of curricula, standards, and mandates that feature critical thinking as a central component or outcome, it is helpful to have a resource that not only engages with but synthesizes these sources into a coherent whole. Haber welcomes this diversity as a strength and notes that while each of these sources has a slightly different take on critical thinking, there is wide overlap and consensus on many of the core points. He explores the tension between those who say that critical thinking should be taught explicitly as an independent discipline and those who advocate for incorporating critical thinking tasks into other content areas like science, reading, and writing, ultimately concluding that both approaches are necessary and beneficial. Similarly, although he does review and speak positively about a number of assessments that purport to measure critical thinking skills, he reminds the reader that a single assessment can only capture a limited view of a student’s critical thinking skills. If practitioners and policy makers are serious about making critical thinking an educational priority, approaches to its assessment and instruction need to be dealt with comprehensively rather than simply as another standard to be tacked on to an existing framework.