TAKE HEED YE YOUTHFUL SCHOLARS: books discovered in your tender years will influence your thinking for decades to come. In 1987 while surfing the stacks of the library of CUNY Graduate School in Manhattan, I plucked off the shelves a copy of Hierarchy: Perspectives for Ecological Complexity by T. F. H. Allen and Thomas Starr (1982). Shortly after this I picked up a copy of a monograph by R.V O’Neill and his colleagues (including T.F.H. Allen) entitled A Hierarchical Concept of Ecosystems. I recall that this volume was regarded with a measure of scorn, albeit a bemused rather than a vicious scorn, by several of the ecologists who taught me at the time (primarily population and community ecologists). It was this book, placing the ecosystem into the framework of a more general systems theory, that ultimately had the longest lasting influence on me in terms of my conception of how the complexities of nature can be made tractable. Hierarchy theory was in the air back them. Perhaps one should say “hierarchy theories” since the observation that many of the complexities in the world can be resolved into structures comprised of parts within parts within wholes is not only a commonplace observation; it is one that has been theorized in many disciplines. Herbert Simon, a leading figure in developing this perspective, was an economist, Ilya Progogine, a chemist, Howard Pattee, a theoretical biologist, Jean Piaget a developmental psychologist. Hierarchy theory draws upon more general systems theory developed by luminaries such as Ludwig von Bertalanffy and James Grier Miller, both theoretical biologists. These early students of complex systems developed ways of thinking about commonalities between disciplines whose objects were structured as nested sets of parts within wholes (in more mathematical terms, hierarchies are a partially ordered set).
