To intervene in such situations the "soft systems" approach uses the notion of a "system" as an interrogative device that will enable debate amongst concerned parties. In its 'classic' form the methodology consists of seven steps, with initial appreciation of the problem situation leading to the modelling of several human activity systems that might be thought relevant to the problem situation. By discussions and exploration of these, the decision-makers will arrive at accommodations (or, exceptionally, at consensus) over what kind of changes may be systemically desirable and feasible in the situation. Later explanations of the ideas give a more sophisticated view of this systemic method and give more attention to locating the methodology with respect to its philosophical underpinnings. It is the earlier classical view which is most widely used in practice.