That is the subtitle of Cheryl Misak’s intellectual biography of the great British polymath Frank Ramsey, who was born on this day (22 February 1903) twelve decades ago. Among many other things, Ramsey was one of the founders of the subjective interpretation of probability, an influential theory that has shaped my own view of the world. I will have more to say about subjective probability in my next post. In the meantime, check out this excellent excerpt from Misak’s beautiful book.