The hydraulic principle

Abstract

SYNOPSIS. AS theory rules method, the methodological procedures applied to morphological explanation have to be derived from the law-like properties of the objects under investigation. The explanation of organismic constructions has to be based on the hydraulic principle which describes organisms as systems composed of fluid contained within flexiblemembranes. This insight establishes a supra-molecular causal principle which, in its generality for morphological explanation, parallels the biochemical principles of molecular biology on the molecular level. Every form and architectural arrangement has to be conceived as the result of the form-enforcing influence of mechanical elements that operatewithin an integrated mechanically coherent system. An adequate explanation of morphological configuration has to elaborate the organization of the constructional whole and explain its properties as the result of a gradual transformation process that is constrained by internal mechanical principles. The theories developed by such a procedure are open to criticism and can be tested and corroborated by reference to experiments conducted by nature. © 1988 by the American Society of Zoologists.