In this essay I first provide an analysis of various community concepts. Second, I evaluate two of the most serious challenges to the existence of communities—gradient and paleoecological analysis respectively—arguing that, properly understood, neither threatens the existence of communities construed interactively. Finally, I apply the same interactive approach to ecosystem ecology, arguing that ecosystems may exist robustly as well. ‡I would like to thank to the participants at the Ecology and Environmental Ethics Conference at the University of Utah, the Philosophy (...) of Ecology Conference hosted by the University of Brisbane, and those participants in a session at the Philosophy of Science Association Meeting in Vancouver, British Columbia for helpful discussions of this essay. Specific thanks go to Mark Colyvan, Greg Cooper, Steve Downes, Chris Elliott, Marc Ereshefsky, Paul Griffiths, Jesse Hendrikse, Greg Mikkelson, Anya Plutynski, Kate Ritchie, Sahotra Sarkar, Kim Sterelny, and Rob Wilson. †To contact the author, please write to: Department of Philosophy, Lewis and Clark College, 0615 SW Palatine Hill Road, Portland, OR 97219; e-mail: [email protected]. (shrink)

Biology above the level of the individual organism ? population ecology and genetics, community ecology, biogeography and evolution ? requires the study of intrinsically complex systems. But the dominant philosophies of western science have proven to be inadequate for the study of complexity:(1)The reductionist myth of simplicity leads its advocates to isolate parts as completely as possible and study these parts. It underestimates the importance of interactions in theory, and its recommendations for practice (in agricultural programs or conservation and environmental (...) protection) are typically thwarted by the power of indirect and unanticipated causes rather than by error in the detailed description of their own objects of study.(2)Reductionism ignores properties of complex wholes; the effects of these properties are therefore seen only as noise; this randomness is elevated into an ontological principle which leads to the blocking of investigation and the reification of statistics, so that data reduction and statistical prediction often pass for explanation.(3)The faith in the atomistic nature of the world makes the allocation of relative weights to separate causes the main object of science, and makes it more difficult to study the nature of interconnectedness. (shrink)

A phenomenological community is an identifiable assemblage of organisms in a local habitat patch: a local wetland or mudflat are typical examples. Such communities are typically persistent: membership and abundance stay fairly constant over time. In this paper I discuss whether phenomenological communities are functionally structured, causal systems that play a role in determining the presence and abundance of organisms in a local habitat patch. I argue they are not, if individualist models of community assembly are vindicated; i.e., if the (...) presence of one species is not typically explained by the presence or absence of specific other species. I discuss two alternatives to in- dividualism, and conclude by arguing for a dimensional model of phenomenological communities. The causal salience of a phenomenological community depends on three factors: the extent to which it is internally regulated, the extent to which it has robust boundaries, and the extent to which it has emergent properties. I conclude by using this model to frame a natural research agenda for community ecology. (shrink)