The naked monad, he says, has perceptions without relief, or "enhanced flavor"; it is in a state of stupor. Death, he thinks, may produce this state for a time in animals. The monads completely fill the world; there is never and nowhere a void, and never complete inanimateness and inertness. The universe is a _plenum_ of souls. Wherever we behold an organic whole, (_unum per se_,) there monads are grouped around a central monad to which they are subordinate, and which they are constrained to serve so long as that connection lasts. Masses of inorganic matter are aggregations of monads without a regent, or sentient soul (_unum per accidens_). There can be no monad without matter, that is, without society, and no soul without a body. Not only the human soul is indestructible and immortal, but also the animal soul. There is no generation out of nothing, and no absolute death. Birth is expansion, development, growth; and death is contraction, envelopment, decrease. The monads which are destined to become human souls have existed from the beginning in organic matter, but only as sentient or animal souls, without reason. They remain in this condition until the generation of the human beings to which they belong, and then develope themselves into rational souls. The different organs and members of the body are also relatively souls which collect around them a number of monads for a specific purpose, and so on _ad infinitum_. Matter is not only infinitely divisible, but infinitely divided. All matter (so called) is living and active. "Every particle of matter may be conceived as a garden of plants, or as a pond full of fishes. But each branch of each plant, each member of each animal, each drop of their humors, is in turn another such garden or pond." [23] [Footnote 23: _Monadol._ 67.] The connection between monads, consequently the connection between soul and body, is not composition, but an organic relation,--in some sort, a spontaneous relation. The soul forms its own body, and moulds it to its purpose. This hypothesis was afterward embraced and developed as a physiological principle by Stahl. As all the atoms in one body are organically related, so all the beings in the universe are organically related to each other and to the All. One creature, or one organ of a creature, being given, there is given with it the world's history from the beginning to the end. _All bodies are strictly fluid; the universe is in flux_.