Dear Don,
I thought that human's pelvis naturally does not be hold in a midway position. It appears a little bit antiversion.I was taught to " pull" it up for vertical alignment.
But last night , someone told me that hip hip should raise a little bit upward and backward ...
When I returned home, I lain prone on the floor, the similar sense noted : my pelvis has slightly upward and backward with flat torso.
These two oppositive views confused me . What do you think of it ?

"natural" is mostly a measure of what you did in your life up to yesterday. Good dance posture can be a natural body position if the muscles and experience support it.

Dear Don,
Thank you very much for your prompt and clear definition about " natural".
Mid-way pelvis+ "long" torso + softened flexed knees help me to stand vertically and stably.
Now I am able to pay more attention to my frame and ankles . It is desirable to move smooth with beautiful shape.

Anon - I like your explanation that ""natural" is mostly a measure of what you did in your life up to yesterday." As a person with deep lordosis (lower back curve) I have had to learn the hard way that although it feels "natural" to me, it is not the best shape for the body. All of the major body work schools (Rolfing, Hellerwork, Feldenkrais, Alexander), as well as many schools of yoga (Iyengar in particular) concentrate on getting the bones of the body aligned and one of the main areas is the pelvis. Very few people seem to have a naturally neutral pelvis position. I find that when I can get the nice long lumbar and a relatively neutral pelvis position, I can both extend the back leg better and also it reduces the tendency for me to "fall into" my partner on forward steps.

Anonymous. On my tape John Wood said. Let all your bones hang in their natural position. Which is pretty well what you are saying. What could be more natural and easy to understand.

But the correct position will be decidedly un-natural for those who have spent the last decade or two with their lower back out of alignment. Despite it's name, homo sapiens is a creature of habit.