is determined not by the density of matter but by the density of vibrations. The speed of vibrations of a matter indicate the degree of intelligence of the given matter. You must remember that there is nothing dead or inanimate in  nature. Everything in its own way is alive , everything in its own way is intelligent and conscious.  Only this consciousness and intelligence is expressed in a different way on different levels of being, on different scales. The degree of consciousness corresponds to the degree of density or the speed of vibrations. This means that the denser the matter the less conscious it is, the less intelligent. And the denser the vibrations, the more conscious and the more intelligent the matter.

Excerpts from P.D.Ouspensky In Search of the Miraculous