Heaven and man are mutually responsive

Man and his natural environment bear certain similarities to each other and are interactive. This principle has multiple facets:

Naïve correspondences such as heaven has the sun and moon; man has two eyes;
The correspondence between the phases (metal, wood, water, fire, and earth) and the organs of the five viscera (lung, liver, kidney, heart, and spleen);
Correspondence in the doctrine of periods and qì and its practical application of the midday-midnight point selection;
The guideline applied in the treatment and prevention of disease of acting in accordance with seasonal, geographical, and personal factors.