Concepts extract and make visible a concept As a 'fixed point' for generating alternatives To strengthen it. "When we extract a concept we can strengthen it through a deliberate improvement effort. We can remove faults and weaknesses and enhance the apparent power of the concept." Change--"Once we know the concept we can decide to change it." We often work at the idea level, and need to 'pull back' to find the concept. Stop sometimes and ask "What is the general method here?" and similar questions. How do we pick a "useful" level of abstraction for concepts? Try one, then make it more general and more specific and see if those are easier to use. If so, change. Types of Concepts (p. 142) "From the point of view of philosophical definition, dealing with concepts is very frustrating because there are different levels of concepts. There is no point whatsoever in getting bogged down in philosophical gymnastics. From a practical point of view you simply try different versions of the possible concepts and then chose whichever one seems most useful to you." Purpose concepts--What are we trying to do? What is the purpose? Mechanism concepts--How does it work? How does it achieve the purpose? Value concepts--why is this useful? What value does it provide?