Edward De Bono, the man who coined the term ' lateral thinking', also waxes lyrical about the traps of dialectical thinking driven to excess.
See particularly his books: Parallel Thinking and Water Logic. They contain some useful tools for facilitating and mediating processes.
Most book shops carry a selection of his books as Penguin editions.
Useful is this tool based on 6 thinking hats for guiding thinking processes from the book of the same name.