This book is a full-fledged discussion of human nature, how we can know it, and what the implications are for political and social relations. The author confronts opposing philosophical positions with eminent fairness, and successfully shows why they lead to different, and morally wrong, policy prescriptions. His own argument clearly demonstrates that political principles require a more fundamental philosophical foundation for their intelligible defense and that the specific politics one espouses will be intimately affected by variations in those basic positions.