A key distinction that Nguyen makes is between “thought” and “thinking.” Thought occurs naturally and spontaneously—it is impossible and unnecessary to stop one’s thoughts from entering the mind. They are the way one processes the world and articulate one’s emotions. A person cannot function, much less be happy, without thoughts. “Thinking,” on the other hand, is the act of contemplating one’s own thoughts, most often from the standpoint of evaluating threats. Negative emotions in particular can trigger a wave of anxiety regarding what they signify about a person’s condition and the long-term implications. Nguyen’s main argument is that thinking must be contained as much as possible, though not entirely, or else it will consume a person with anxiety and fear.

To illustrate his points, Nguyen makes frequent reference to the Zen tradition of Buddhism. Zen originated in China most likely in the seventh century, with some of the beliefs of Taoism incorporated into Mahayana Buddhist practice. Like other forms of Buddhism, Zen places a heavy emphasis on meditation. Unlike other forms, it tends to rely on stories and brief aphorisms to convey its teachings, with less emphasis on doctrine. It also believes in the possibility of sudden enlightenment, whereas traditional practice emphasizes the need for extensive training, typically under a master.