The Buddha saw the core problem in human life as "ignorance"(avijjā), not an ignorance of facts or information, but rather a not-knowing about the basic nature of reality and our experience. The Dalai Lama tells us: "There is a fundamental disparity between the way we perceive the world, including our own experience in it, and the way things actually are." We explore how similar understandings of a core human ignorance are found in Plato, Christian and Islamic traditions, and in later Buddhist traditions. The Buddha said, in particular, that we are ignorant about impermanence, dukkha (or reactivity), and the nature of the self. We look into some of the main habitual constructions of experience, including a sense of permanent, stable, separate external objects, and a sense of a separate, independent self, pointing to ways of exploring such constructions meditatively. We also point to experiences in which we go beyond such constructions, in meditation and also in "flow" experiences. The talk is followed by discussion.