Assumption Reversal

Origin. de Bono; distinct from Reversal in that it inverts premises rather than the objective.

Mechanism. Enumerates the propositions that must be true for the current approach to be correct, then negates each in turn and asks what design each negation implies. Where Reversal inverts the goal, this inverts the ground.

Procedure. List the assumptions, including the ones too obvious to state — especially those. Reverse each singly. For each reversal, design forward. Note which reversals produce a viable design; those assumptions were never binding.

Applies to. Mature domains where a design has settled around premises no one has restated in years.

Limitations. Reversing several assumptions at once produces incoherence rather than insight. One at a time, or the exercise cannot attribute the result.