Born in 1918 in New York, awarded a doctorate in analytical chemistry (1944), Leonard K. Nash enjoyed a distinguished career at Harvard, holding a chair of chemistry from 1959 to 1986. Conducting research in thermodynamics and statistical mechanics, Nash authored successful textbooks, some of which remain in print (e.g. Elements of Chemical Thermodynamics, and Elements of Statistical Thermodynamics).This essay describes the theory of science that Nash developed in a book he published in 1963, The Nature of the Natural Sciences. The (...) present author is of the view that Nash's neglected theory is worth retrieving, as one that is likely to kindle the interest of historians of metascience on several counts. Part of .. (shrink)