In calling society an ecological system we are not merely using an analogy; society is an example of the general concept of an "ecosystem" that is, an ecological system of which biological systems - forests, fields, swamps - are other examples.
Kenneth E. BouldingIt is clear that the building of models is not a purely mechanical process but requires skill of a high order - not merely mathematical skill but a sensitivity to the relative importance of different factors and a critical, almost an artistic, faculty in the selection of behaviour equations which are reasonable, tentative hypotheses in explaining the behaviour of actual economies.
Kenneth E. Boulding