Facts are facts, we often say with certainty; but values--well, they're relative. But every day we are confronted with situations where these simple distinctions begin to blur--whether our concerns are the roots of crime and violence, the measure of intelligence, the causes of disease, the threat and promise of genetic engineering. Where do our "facts" end and our "values" begin? Recent developments in neuroscience have begun to shed light on this confusion, by radically revising our notions of where human nature ends and human nurture begins. As Edward Hundert--a philosopher, psychiatrist, and award-winning educator--makes clear in this eloquent interdisciplinary work, the newly emerging model for the interactions of brain and environment has enormous implications for our understanding of who we are, how we know, and what we value. "Lessons from an Optical Illusion" is a bold modern recasting of the age-old nature-nurture debate, informed by revolutionary insights from brain science, artificial intelligence, psychiatry, linguistics, evolutionary biology, child development, ethics, and even cosmology. As this radical new synthesis unfolds, we are introduced to characters ranging from Immanuel Kant to Gerald Edelman, from Charles Darwin to Sigmund Freud, from Jean Piaget to Stephen Hawking, from Socrates to Jonas Salk. Traversing the nature-nurture terrain, we encounter simulated robots, optical illusions, game theory, the anthropic principle, the prisoner's dilemma, and the language instinct. In the course of Hundert's wide-ranging exploration, the comfortable dichotomies that once made sense (objectivity-subjectivity, heredity-environment, fact-value) break down under sharp analysis, as he reveals the startling degree to which facts are our creations and values are woven into the fabric of the world. Armed with an updated understanding of how we became who we are and how we know what we know, readers are challenged to confront anew the eternal question of what it means to live a moral life.