I agre with the point about structures being a fundamental proposition. In addition I paraphrase a comment by Jay Forrester at the Boston SDS conference. At one point he rose and said [approximately] 'anything that changes is governed by feedback loops.' At which point he sat down! I think that a reasonable undertanding of systems thnking involves looking for the feedback loops that drive the system.
Rich Langheim Associate Professor of Education Ramapo College of New Jersey