Method and metaphysics in Clements’s and Gleason’s ecological explanations

To generate explanatory theory, ecologists must wrestle with how to represent the extremely many, diverse causes behind phenomena in their domain. Early twentieth-century plant ecologists Frederic E. Clements and Henry A. Gleason provide a textbook example of different approaches to explaining vegetation, with Clements allegedly committed, despite abundant exceptions, to a law of vegetation, and Gleason denying the law in favor of less organized phenomena. However, examining Clements’s approach to explanation reveals him not to be expressing a law, and instead to be developing an explanatory structure without laws, capable of progressively integrating causal complexity. Moreover, Clements and Gleason largely agree on the causes of vegetation; but, since causal understanding here underdetermines representation, they differ on how to integrate recognized causes into general theory—that is, in their methodologies. Observers of the case may have mistakenly assumed that scientific representation across the disciplines typically aims at laws like Newton’s, and that representations always reveal scientists’ metaphysical commitments. Ironically, in the present case, this assumption seems to have been made even by observers who regard Clements as naı¨ve for his alleged commitment to an ecological law.