r Ultimate Ground of Existence. [9]
They gave to it the name _t'ai chi_, and represented it by a concrete
sign, the symbol of a circle. The complete scheme shows the evolution
of the Sixty-four Diagrams (_kua_) from the _t'ai chi_ through the
_yang_ and the _yin_, the Four, Eight, Sixteen, and Thirty-two
Diagrams successively. This conception was the work of the Sung
philosopher Chou Tun-i (A.D. 1017-73), commonly known as Chou Tzu,
and his disciple Chu Hsi (A.D. 1130-1200), known as Chu Tzu or Chu
Fu Tzu, the famous historian and Confucian commentator--two of the
greatest names in Chinese philosophy. It was at this time that the
tide of constructive imagination in China, tinged though it always
was with classical Confucianism, rose to its greatest height. There
is the philosopher's seeking for causes. Yet in this matter of the
First Cause we detect, in the full flood of Confucianism, the potent
influence of Taoist and Buddhist speculations. It has even been said
that the Sung philosophy, which grew, not from the _I ching_ itself,
but from the appendixes to it, is more Taoistic than Confucian. As it
was with the P'an Ku legend, so was it with this more philosophical
cosmogony. The more fertile Taoist and Buddhist imaginations led to the
preservation of what the Confucianists, distrusting the marvellous,
would have allowed to die a natural death. It was, after all, the
mystical foreign elements which gave point to--we may rightly say
rounded off--the early dualism by converting it into monism, carrying
philosophical speculation from the Knowable to the Unknowable, and
furnishing the Chinese with their first scientific theory of the
origin, not of the changes going on in the universe (on which they
had already formed their opinions), but of the universe itself.

Chou Tzu's "T'ai Chi T'u"

Chou Tun-i, appropriately apotheosized as 'Prince in the Empire of
Reason,' completed and systematized the philosophical world-conception
which had hitherto obtained in the Chinese mind. He did not ask his
fellow-countrymen to discard any part of what they had long held in
high esteem: he raised the old theories from the sphere of science to
that of philosophy by unifying them and bringing them to a focus. And
he made this unification intelligible to the Chinese mind by his famous
_T'ai chi t'u_, or Diagram of the Great Origin (or Grand Terminus),
showing that the Grand Original Cause, itself uncaused, produces the
_yang_ and the _yi