In William Issacs book on the “Dialogue and the art of thinking together” he introduces the Four-Player System originally developed by David Kantor. This is a very important technique for supporting real collaborative thinking in teams.
In any productive group thinking dialogue all four of the following roles should be in play:
Without Movers there is no direction
Without Opposers there is no correction
Without Followers there is no completion
Without Bystanders there is no perspective
The roles do not all need to be in play at the same time but need to have been played before the thinking concludes.