What is the nature of physical pain? Why do we even experience it? Is there one type, or many? Do people experience pain differently? What is happening in our brains and our bodies when we experience pain? What is the biological link between pain and addiction? In this episode Clifford Woolf, Professor of Neurobiology at Harvard Medical School and a renowned expert on understanding pain, shares with with a16z's Hanne Tidnam all we know about the biology of pain. Technology is enabling a new, deeper, and much more complex understanding of pain—which pathways and neurons are activated in the brain when, what patterns might represent which experiences of pain. We now understand that the notion of pain as a simple switch that can be switched on or off (you have pain/you don't have pain) and measured by categories like mild, moderate, or severe is just incorrect. Woolf describes the 4 different broad types of pain we in fact experience, what the purpose of each is, and what it means now that we can phenotype them and begin to understand them as distinct. Now that we have this deeper and much more complex understanding of pain, what does it mean for how we can treat pain in the future, and where we can intervene?