Understanding psychology and economics in mechanical terms requires looking at specific concepts of psychology and economics from the mechanical point of view. If we look to the literature, however, we find that the cognitive sciences study a wide range of possible or hypothesized psychological organizations as explanations of human thought. For example, the ideally rational agents of economics have one kind of mind, a kind very different from almost all known human minds. But even among humans, individual minds have very different characters, exhibiting different levels of intelligence at different tasks, different temperaments, different degrees of adaptability, and so on. The well-known Myers–Briggs test (Myers & Myers 1980), to give another example, sorts minds into sixteen well-populated classes. These classes correspond to recognizable and common types of personal character, types that give some insight and enable reasonable, though not perfect, predictions of individual behavior.

It does not take deep reflection to realize that if we are already on page 225 and just starting the mechanical examination of psychology and economics, we cannot hope to examine all the concepts of all hypothesized mental organizations in this book, no matter how long, without exhausting all patience. I therefore undertake to examine the structure and mechanical nature of some special kinds of minds that serve to illustrate the mechanical nature of thinking, in part to open the special classes to mechanical investigation, and in part to suggest ways of understanding other kinds of minds in mechanical terms.