DOI
http://www.tandfonline.com/doi/abs/10.1080/10286608.2013.853749

Summary
It is argued that systems approaches from even different backgrounds can nevertheless end up with similar features, promoting the idea that such approaches are grounded in reality, as science is taken to be. The systems approaches of Peter Checkland and David Blockley, from management and engineering backgrounds, respectively, are explored with a view to highlighting similarities and differences. This is done by looking at summaries of their approaches and examples of their use. Both Checkland’s and Blockley’s approaches have a set of common features such as layers; purpose; top-level outcome; attributes such as what, how and why; measures; uncertainty and conversation. Such similarities prompt us to see systems approaches as being objective rather than relativistic. The differences in their overall approaches reflect the hierarchically structured nature of reality that requires hierarchically ordered approaches to deal with it.

Relevance for Complex Systems Knowledge
The paper compares to different approaches to systems studies and find that despite the different entry points they end up with rather similar descriptions. The most interesting part is on what grounds they find the distinctions between the two approaches. First they distinguish between systems approaches within engineering ranging from hard systems models characterised by optimisation, through systems dynamics to softer systems approaches that focus more on purpose, process and people. Then the authors continue to make distinctions between soft system approaches. The notion of ‘soft’ arises because of human agents in systems, giving rise to human perception of the world and human purpose directed towards that world. For Blockley, this adds complexity to modelling, since every ‘hard’ system is embedded within a ‘soft’ one; he would like to be seen as integrating soft and hard systems. For Checkland, however, it is only human perception and purpose that can be modelled (i.e. in an exclusively soft system), because the world is too chaotic to be modelled.
Perhaps the crucial difference between hard and soft systems, as expressed by Checkland, is his view of the world and the models we create of it. According to him, in hard systems, the world is treated as systemic and models of it as systematic, whereas in soft systems, the world is acknowledged as chaotic and models of it as systemic. Checkland’s models are not those of the world but of the world as perceived by humans.

Point of Strength
This article would fit well into a course introducing different approaches to systems thinking. The distinctions made are clear and thought provoking.