The number three is indissolubly connected with the very idea of relatedness. Three as a class concept is an abstraction from experience - three as a relationship is an integral part of experience itself.
All real relationships are reducible to the combination of three independent terms - affirming, denying, and reconciling elements - complex multi term relationships always reducible to triads of the three elements.
The most important, and sometimes the most difficult, idea to be grasped is that a relational triad is constituted only to the extent that the 3 terms present are independent. If any one of the 3 terms can be inferred from the other two, then we are dealing with wholeness or polarity, not a
relationship.
It must be further noted that each of the 3 terms makes its own specific contribution to the relationship. One of the terms will always have the character of affirmation, or activity; the second will have that of denial; while the third will appear neither as active nor passive, but as the reconciliation of the other two. Affirmation is always opositive and active, but it can have many different shades; denial can range from violent opposition to inertness and passivity; and within this range there can be such other characteristics as receptivity, response, and co-operation. The third character may be no more than the result of the meeting of active and passive forces, or it may appear as an act of freedom bringing into existence a situation that without it would not have arisen at all.