Harmony in Nature

I had a mind-boggling experience today. I visited an Anasazi site in Aztec New Mexico (google Aztec Ruins New Mexico). It was mistakenly thought that the pueblo was Aztec, but it ain't. It was inhabited 1000-1200 by people that are called 'ancestral pueblo' by the Park Service, since Anasazi is a Navajo term that can be translated as "invaders."
Anyway, the question always comes up, 'Why did they leave?" And the answer can be found in Jared Diamond's book Collapse. They outbred and outpopulated their ability to sustain themselves, stripping the land for miles around them.
I mention this because of my belief that the Anasazi were pretty much the way we are. People are people, in all times and all places. If we wonder why such and such a society did something, we need only ask, "What would we do in a similar situation?"
I mention this because there are people who simply will not accept the explanation that the Anasazi ruined their environment, because they were a non-industrial people, and, living in harmony with Mother nature, couldn't possibly have done bad things to Mom. I have news for those people: They could have and did. Living in harmony with nature means being hungry, diseased, and probably eaten. The "Harmony with nature" philosophy that you hear from Native Americans is probably a modern romanticism about their ancestors, who only wanted to live a little while longer, and probably paid as much attention to their religion as we do to ours. Which is to say, almost none.

Magic

The human body has a remarkable ability to respond to invisible influences. For instance, let's say you stay out in the sun too long. Next day, your skin will be red, or if you're lucky, tan. Your skin, without your knowledge or consent, allows melanin to move to the surface of the skin in response to the ultraviolet invasion. Or, say, you are walking along and trip a little. Your body responds to the mysterious force of gravity in a very complicated way, starting with the movement of fluid in the inner ear, and you catch yourself.
Now, here's my point: any feelable force in the universe will be reflected in some bodily function that deals with that force. Take the magnetic flux that moves from pole to pole. Humans don't respond to it much, as far as we know, but birds do, and there are neurological indications of how they do it.
So, if there is a force, however mysterious, that acts on humans and that influences our survival, we will have developed a mechanism for dealing with it. The key word here is mechanism. We had melanin long before we learned about the ultraviolet. Much of our entire body mechanism is geared to coping with gravity (jellyfish don't have an inner ear). Bugs have a wonderful six-legged gait that keeps them on an even keel.
So, what about ki, mana, and other posited forces of nature? I believe that if they exist there is a discoverable, chartable, testable mechanism that responds to them. No mechanism; they don't exist. That's my story and I'm sticking to it.