It is widely recognized that Leibniz's philosophical thought is deeply influenced by the mathematics, physics and philosophical theology of his era. Justin E. H. Smith's Divine Machines argues that many of Leibniz's most central philosophical doctrines are similarly bound up with the life sciences of his time, where the “life sciences” are understood very broadly to include fields as diverse as alchemy, medicine, taxonomy, and paleontology. Smith's groundbreaking exploration represents an important contribution to our understanding of both Leibniz's philosophy and the study of life in the early modern era. It is to be recommended to historians, philosophers, and historians of philosophy alike. Below I highlight four central topics in Smith's book, raising some reservations along the way.
1. First Things
The first part of Divine Machines is divided into two chapters, the first of which explores Leibniz's views on medicine. As Smith shows in detail, Leibniz, like many of his early modern contemporaries, was deeply interested in the study of medicine and its ancillary fields. Thus in a letter of 1697, Leibniz declares medicine to be “the most necessary of the natural sciences” and maintains that it is “the principal fruit of our knowledge of bodies,” since the promotion of health may allow us to “work for the glory of God” (26). This lofty aim no doubt bolstered Leibniz's interest in (what we would call) chemistry and anatomy (28-33, 48-58). In connection with the former, Smith provides a rather detailed account of Leibniz's treatise on the “purgative power” of the ipecacuanha root, a treatise that Smith calls, with (I assume) unintentionally faint praise, “the most comprehensive and influential of Leibniz's contributions to the history of medicine and pharmacy” (40). In connection with anatomy, Smith chronicles what he sees as a shift in Leibniz's enthusiasms away from vivisection towards microscopy.