The Tao of Instructional Models And this Way of nature is the
way in which all things come into being out of darkness into
light, then pass out of light back into darkness, the two
principles - light and dark - being in perpetual interaction,
and in variously modulated combinations, constituting this whole
world of "ten thousand things." The light and the dark of this
system of thought are named respectively yang and yin, which are
words referring to the sunny and the shady sides of a stream.
Yang is of the sunny side; yin the shady. On the sunny side
there is light, there is warmth, and the heat of the sun is dry.
In the shade, there is the cool, rather moist; light, hot, and
dry: earth and sun in counteraction. These are associated,
further with the female and the male as the passive and active
principles. There is no moral verdict here intended; neither
principle is better than the other, neither "stronger" than the
principles on which all the world rests, and in their
interaction they inform, constitute,