The Organism as a System: Insights from Paul Weiss

Despite the remarkable successes of molecular biology over the past three quarters of a century, there is growing recognition that organisms must be understood as integrated systems if we are to fully grasp their most distinctive features. Yet considerable uncertainty remains (and, in some quarters, outright skepticism) about how 'systems thinking' can actually deepen our understanding of organisms-beyond simply reminding us of such familiar maxims as 'the whole is more than the sum of its parts'. In this paper, I draw on the largely forgotten organicist ideas of the experimental and theoretical biologist Paul Weiss (1898-1989) to outline a workable, intuitive, and non-formal systems-oriented conception of the organism, and proceed to illustrate its value and effectiveness across a range of explanatory contexts. Specifically, I argue that a proper understanding of the organism as a system-lucidly anticipated by Weiss more than half a century ago-provides the necessary conceptual resources to diagnose and overcome the problems with four prominent doctrines that remain deeply entrenched in contemporary biology: reductionism, genocentrism, determinism, and mechanicism.