The Four Pillars outlines all possible linear directional possibilities in the eight *gua*, or trigrams. It also corrects a persistent misunderstanding pertaining to the assigning of numerical values to Yin & Yang. From the moment Gottfried Leibniz first published his binary attributions to the I Ching, there has existed an unspoken assumption that Yins should always receive a value of 0 and Yangs, 1. This probably stems from the notion that Yins are traditionally *even* and Yangs *odd*, but even & odd, passive & active, dark & light attributions do not concern us in chronological arrangements. The only thing that concerns us is *before* and *after*. When a chronological order begins from Heaven, Heaven should always carry the *alpha* numerical value of 0 proceeding to its polar opposite (Earth) which carries the *omega* property of  7 in whole trigrams. When we are beginning from Earth, proceeding to Heaven, the opposite should always follow, with Earth receiving a numeration of 0 and Heaven 7. Only in this way will our numbers mesh properly with our line values in a consistent and harmonious way.

There are thus no less (and no more) than 4 chronological possibilities available to us in trigrams and all of them have specific value to us in different kinds of situations. In Trigrammal Field applications it is the *Heaven Descending* and *Earth Ascending* arrangements that we are the most concerned with since these facilitate the union of Earth (Below) with Heaven (Above) in a way that is natural and correct from the viewpoint of Man (Middle). The Heaven Descending arrangement is also referred to throughout my work as the P'an Ku Arrangement, referring to the historical P'an Ku from pre-Imperial Chinese history. It also shows up in the Tai Hsuan Ching arrangement as a logical binary subset of the 729 ternary hexagrams within that system. The Earth Ascending arrangement is referred to as the Nu Kua arrangement, also from pre-Imperial China and typically assigned to Fu Hsi (The Yellow Emperor), though in truth this arrangement can be tracked historically to well before Fu Hsi's own time

Additional Forum Discussion of the Four Pillars and its application to trigrammal fields can be viewed here.

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