Perhaps no idea or concept in psychology has been investigated as comprehensively—or so controversially—as human intelligence. This attention is long-standing: Theories of intelligence predate [Page 481]the formal establishment of psychology as a science by millennia. Although perhaps more commonly associated with philosophy, the ideas of Aristotle, Socrates, and Plato all contribute to the foundation of our understanding of the nature of intelligence. Their ideas on topics as diverse as the origin of ability, the mind-body relationship, and general inquiry methods continue to inspire thinkers and helped shape the ideas of those who shape modern psychology and intelligence theory. Philosophers, psychologists, and educators have spent much of the past century and a half building on the foundations of the ancient thinkers, and a variety of theories ...