Modern psychology is a child of the scientific revolution. Without the systematic application of reason and observation that forms the foundation of the scientific method, there would be no modern psychology. Nonetheless, contemporary psychology is not without precedents, and within Western history there are many precursors, ancestors so to speak, of psychology as we know it today. Ancient Greek philosophy, medieval Christianity, and post-Renaissance philosophers of the past several centuries all addressed the core questions of psychology in ways that both differed from and anticipated much of what we know today.

Twenty-five hundred years ago, ancient Greek philosophers turned their remarkably sophisticated inquiries away from the whims of the gods and toward questions of the natural world. Questions about humanity’s place in the world naturally followed. What is knowledge and how do we gain it? What is our relationship with emotions? While some of their answers to these questions appear bizarre by modern standards, much of it remains strikingly current.