Gurdjieff's Law of Three states that each phenomenon, from the cosmic to the sub-atomic, springs from the interaction of three forces: the first, or Holy Affirming, being active; the second, or Holy Denying, passive; and the third, or Holy Reconciling, neutralizing.
The forces are active, passive and neutralizing only with respect to the phenomenon at hand. Thus one and the same force may play very different roles in different phenomena and no phenomenon is isolated. The Law of Three deals with the single occurrence, but no single occurrence occurs that is not part of some process. The Law of Seven deals with how a process moves through distinct stages in time.
The formulation 'The higher blends with the lower in order to actualise the middle' , is clear in the following: the sperm merges with the ovum to create the embryo or alternatively the sexual drive is inhibited, giving rise to ‘sublimation' or ‘complex', a teacher relates with a pupil ensuring transmission, etc.
In other examples, the third force is a catalyst or arbiter which determines the outcome of the encounter of the active and passive forces. For example flour and water become bread only when bonded by fire, plaintiff and defendant have their case resolved only through a judge, the soul in potential asserts itself over the body through the application of the Work.
The human mind is geared towards thinking in terms of a single force or at most two and does not have a natural ability of discerning the three forces at work in any given situation. Rigid 'formatory' or 'mechanical' thinking tends to only see yes and no or true and false or good and bad. Introducing the notion of third force as a representative of context or consciousness can broaden the mental process. Still, we may not give fixed meanings to the three forces.
The Buddhist notion of the middle path may be seen as a special application of the Law of Three: For example, the extremes of asceticism and gluttony can be reconciled to right action by the Dharma, thus moving on from the body-centricity implicit in the original tension between deprivation and indulgence. The mode of thinking in terms of 'neither this, nor that' has an implicit openness for the concept of third force, whatever the context may be.