I recently read a book about the wise men of ancient China called the fangshi, a fascinating book that catalogues stories from the lives of these men, involving their predictions, connection to spirits, and the natural magic they wielded. The following quote is attributed to the fangshi Kuan Lu, who lived in the 3rd century (note: a "li" is a distance measurement):
From Doctors, Diviners, and Magicians of Ancient China: Biographies of Fang-shih, compiled by Kenneth DeWoskin (1983)
"When the bright sun mounts the heavens, its light circulates over a vista of ten thousand li. But when it enters the ground, there is not even a ray equal to the glow of a small burning coal. The full moon on the fifteenth day illuminates the night with its clear radiance, so brightly that one can see off in the distance. But when morning comes, its shine cannot even rival that of a mirror. Now, beyond the sun and the moon, there is the systematic regularity of yin and yang. This system of yin and yang is woven into the infinite variety of things. It is in accord with this system that the birds and the beasts are undergoing endless transformations. That being so, how much more must it be true of men! By ingenuity one can gain mastery over this system and with spiritual prowess can grasp the unfathomable."
The fangshi (or "fang-shih", depending on how you want to write it from Chinese), form an important part of Chinese legend and philosophy. They were solitary men who studied Nature and the esoteric arts, and although there weren't any fangshi organizations or groups, each of them discovered similar practices, so are all called "fangshi." Many of them studied the hexagrams of The Book of Changes (The I Ching) to predict future events. For example, the appearance of certain animals, the flight patterns of birds, the weather, etc. can have significant meanings in people's lives and the affairs of a state if they are interpreted properly.
In ancient times, the fangshi were sought after by kings and nobles for their wisdom, most of which revolved around predicting future events. The fangshi also had a connection to the spirit world, where ghosts of those deceased as well as spirits and demons dwell.
In the quote above, we can see why events in Nature reflect human affairs. It's all about the microcosm and macrocosm: as above, so below. As Nature reflects Heaven (or whatever higher world you want to call it), so does the human world reflect Nature. The human world is at the same time a part of Nature as well as a microcosm of its own. Likewise, when something happens in the world below, there is a response that can be read in Nature and even the heavens. For example, Lu says, "When armies move and people suffer, there is a response among terrestrial things, and that means among the mountains, forests, birds, and beasts." Each world has its own "code" that must be studied to read the meaning behind it and how it connects to ourselves and our society.
We also see the idea of the rise and fall of certain forces as they take turns in domination. For example, the moon pales next to a light reflected from a mirror in the daytime. This doesn't mean that moon changes, but that different forces "takes turns" dominating, for they are all part of the cycle of yin and yang (two opposite qualities that describe the world). They are connected, ever transforming into one another. Fire into water, love into hate, light into dark. Hence the well-known symbol:
Likewise, in the human world, we may be powerless against, say, a flood, but by ingenuity, we can rise above it by building a sanctuary on high ground. Most people are unable to extend the years of their lives, but it is said that the many of the fangshi found the secret of immortality, or at least, were able to live extended lives (for example, by performing what is known as fetal breathing, a practice that involves sustaining oneself with as little respiration as possible). This is an example of what Lu means when he said, "By ingenuity one can gain mastery over this system and with spiritual prowess can grasp the unfathomable."
The unseen force that flows between beings and events, between the different worlds (which are in truth all connected) is called ch'i. Ch'i is a life force present in the world and all beings within it. Everything is linked by the flow of ch'i. When there is a disturbance in one world, it is reflected in the others, and will manifest in whatever elements are present in that world--so in Nature, creatures like birds respond to the flow of ch'i, and their movements can have a significance. Elements such as fire, earth, air, and water also have a distinctive ch'i, and being some of the most simple substances in Nature, they are more likely to reflect changes in the heavens and human world. For example, storms (air and water) were often seen as portents for state and military affairs.
All of this may seem to be in the realm of pseudo-science, but I think there is some merit to it. From biology and physics (especially quantum physics), we know the world is all connected, and if someone could read the linkages between things, had an eye for perceiving them, they might be able to read it as the fangshi did. One only has to look at someone like Sherlock Holmes to realize that some people have extremely heightened perceptions so that they can perceive details about world that are hidden to others. In many ways, Sherlock Holmes is a later day version of the fangshi.
It's difficult to properly appreciate the understanding people in the past had of Nature, mostly because, on the whole, our society is out of tune with Nature and regards it with scientific principles rather than trying to connect to its more subtle essence that cannot be laid bare by mathematics, but has to be perceived. Imagine how different it would seem to the fangshi and other philosophers who tried to understand the world, such as Druids and shamans. Their way of understanding the world wasn't wrong, nor is ours, but in many ways, theirs was deeper than our own. They had a spiritual understanding of the world as well as a physical one, and were able to navigate how things were connected, in particular, by the subtle signs revealed in Nature.
That is one of things our science of today is missing. And that, I believe, is where we must reforge our paths if we want to gain a better understanding of our own world and those beyond it.