We consider Wideman's recognition that every project "evolves" through its life cycle as an extremely important metaphysical assumption, and claim that the PMBOK Guide fails in dealing with it. This was not systematically discussed in our original paper, but we are working on this.
Much of current espoused practice seems to be based on a belief that the world can be modeled far in advance and in great detail by skilled planners. This is a Cartesian approach that doesn't hold up in the face of our "first postulate", i.e. that the future is uncertain and unknowable but can be shaped by our actions.
We think we need a project management system that has a very different relationship with uncertainty. In current practice, uncertainty appears to result in change - as if the plan was "correct" and "change" is bad or to be avoided. We cannot model the future in great detail but we can learn as we move into it what is more valuable for clients and effective for suppliers.
Donald Schon has suggested that practitioners know more than they can express. And most are very aware that current practices, particularly planning and control techniques, are problematic. In particular, this leads us to optimize locally at the expense of the project. This in turn leads to tremendously adversarial relations that we then try to manage around with team building and leadership.
We suspect the PMBOK is the normative practice, what people think is right - even if they cannot make it work without doing other things. So, we believe the PMBOK rests on an unsupportable world view.
Howell relates the following story: "I also remember some early work with Alex Laufer where we visited with the best project managers we could find in a number of solid companies. We ask for "old reliable", the person who got the tough projects. We spent several days with each to see how they planned. In every case, they said, "I don't do it right" and tried to refer us to the planning department with the big computers. We stuck with them and eventually observed to one, "you spend a lot of time coping with uncertainty." He almost kissed us. Then Laufer asked: "How do you do that?" and he had no answer. We observed for a while and came to believe that the good ones narrowed, divided and absorbed uncertainty into their decisions."
Now we are convinced that practitioners are ready for words that describe what they really do and concepts that provide a coherent and teachable explanation for those actions. The job of academics is to observe the patterns, name them most typically with terms drawn from other spheres of work, and then make the connections.