what is the "density" exactly means?

[zenmaster]

I'm not sure if it will exactly fit what you're looking for, but Arthur M. Young's "Theory of Process" may help expand your seeking in this direction. The ideas were formally explicated in his book The Reflexive Universe, which I would recommend highly to any seeker who enjoys exploring philosophical interpretations of scienctific knowledge. To get a very basic grasp of his sevenfold structure I would visit this page and go to section C.

In short, I believe that his sevenfold breakdown of the physical universe makes for a good generalization of various relationships between the entities which make up the first 3 densities.

Thanks Poffo. You've reminded me (one who enjoys exploring philosophical interpretations of scientific knowledge) that I have a copy of The Reflexive Universe. Will take a look.