Emails with David Harriman

October 4, 2010

Below are the three emails I sent to Mr. Harriman after I began reading the published version of his book, The Logical Leap: Induction in Physics. Each spawned a thread of interleaved discussion.

Letter to Harriman re book

Email with Harriman re Galileo

Email with Harriman re Newton

Dr. Peikoff said that my criticisms of Mr. Harriman’s book “often go to the heart of the philosophic principles at issue.” Unless indirect references such as the above are included, I would have said “a few times” rather than “often,” but regardless, here is an example, from a discussion about gravity. I express reservations about the principle that an inchoate concept provides a “red light” to induction and sympathize with William Whewell’s view that a concept’s final formation completes rather than begins an induction.

(By the way, my take on this episode is that it is not a story about having or not having a concept but about defining nominally vs. defining causally. I'd say Bacon and Galileo and all those pendulum swingers just before Newton had the same concept of gravity as heaviness with attraction as a possible but unproven cause; Bacon and then Newton insisted gravity should be defined causally. Galileo said that for his purposes a nominal definition was fine. Newton worked out the causal definition and in the process made terrestrial gravity just an instance of universal gravitation, the broader of which came then to be called gravity. The shift from nominal to causal definition often jiggers the boundaries. In this case, it did big time. I sympathize with Whewell here: he says every induction is completed by the forming or re-forming of a concept. For him, an essentialized concept is not the initial step that lets an induction proceed; it is the final step.)

I didn’t mention this in the email exchange (references to Objectivism in my exchanges with Mr. Harriman were rare) but this part of Whewell’s philosophy might fit well with Ayn Rand’s intriguing statement in the ITOE workshops that concepts implicitly contain propositional knowledge.


For those who don’t know him: William Whewell (1794–1866) was the last major advocate for a conception of induction that gained currency in Copernicus’ time and then dominated the philosophy and practice of science from the time of Galileo and Harvey to that of Darwin and Maxwell. It is too bad a discussion of writings on induction from those times was not part of Mr. Harriman’s book. Comparisons between what the scientists were taught to do and what Mr. Harriman said they actually did do would have helped highlight the new and distinctive features of the theory Mr. Harriman presents.