Opposites don't cancel each other out — they define and sustain each other

In Chinese philosophy, yin and yang aren't good versus evil, or even strictly opposites in the Western sense: dark needs light to be visible as dark, stillness only makes sense next to motion. Each is shown containing a seed of the other, chasing each other in a circle, because neither one can exist, or be understood, alone.

— Traditional; systematized in Chinese yin-yang cosmology, I Ching (Book of Changes) — Zhou dynasty, c. 1000–750 BC, with later philosophical development
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