Among other things, Frank Ramsey (b. 1903, d. 1930) was one of the first scholars, along with Bruno de Finetti, to formalize the “logic of partial belief” or the subjective view of probability. (For this reason alone, I count Ramsey as one of my intellectual heroes.) In brief, the subjective view of probability can be expressed in terms of “degrees of belief”–the idea that the probability of a unique event (e.g., whether Disneyland and Disney World will reopen to the public before the end of this month, or whether SCOTUS will overrule Roe v. Wade) does not have to be an objective value but rather can consist of an individual’s personal or subjective judgment about whether the event is likely to occur.
But how did Ramsey discover this revolutionary insight–the idea that probability can consist of a subjective or personal value? Cheryl Misak’s new biography of Frank Ramsey, which is subtitled “A Sheer Excess of Powers,” explores this terrain as well as Ramsey’s many other scholarly contributions. (Dr. Misak is pictured below.) Since Misak’s beautiful book is divided into three broad parts–“Boyhood”, which consists of three chapters devoted to the years 1903 to 1920, i.e. from the year of Ramsey’s birth up to his arrival at Cambridge University; “The Cambridge Man”, which contains seven chapters that describe Ramsey’s undergraduate years at Trinity College as well as his six-month sojourn in Vienna in 1924; and lastly, “An Astonishing Half Decade”, which contains nine chapters and covers the last five years of Ramsey’s short but productive life–I will likewise divide my review into three parts or installments, beginning with my very next blog post, with each post corresponding to one of the parts of Misak’s book. (Note: Although Frank Ramsey made significant contributions to a wide variety of fields, including economics, mathematics, and philosophy, I will focus the rest of my review on Ramsey’s contributions to probability theory.)