This essay extends Levins'' 1966 analysis of modelbuilding in ecology and evolutionary biology. Amodel, as the product of modeling, might bevalued according to its correspondence to reality. Yet Levins'' emphasis on provisionality and changeredirects attention to the processes ofmodeling, through which scientists select and generatetheir problems, define their categories, collect theirdata, compare competing models, and present theirfindings. I identify several points where decisionsare required that are not determined by nature. Thisinvites examination of the social considerationsmodelers are reacting to at the (...) sites of sociality.Modelers must weave socio-ecological webs so thatthe models can be seen to represent their subjectmatter at the same time as the modelers secure thesupport of colleagues, collaborators and institutions,and enjoin others to act upon their conclusions. Notonly do theory justification and theory generationmerge, but the joint project becomes simultaneouslyphilosophical and sociological. (shrink)