T he theories of yin and yang and the five elements (wuxing)form the philosophical basis of traditional Chinese science.Professor Liu Yanchi (1998) suggests the best way for a Westerner to appreciate these theories may be to think of them in terms of concepts like systems theory (which blends the study of quantities with the study of form or pattern) and complexity theory (which tries to explain how something might begin from a random or chaotic state and yet produce complex order).1 Concepts of disorder and randomness-also called chaos-are included in the study of complex systems. Scientifically, a child’s room is not ‘a cluttered mess’, it is a ‘complex environment’ (complex can refer to deliberately created anarchy and to random messiness).