Hi, Clete,
I'm going to try to give a concise, brief, and fairly jargon-free presentation of the Buddhist views on the subject of unity and multiplicity. You'll have to tell me how I do!
As I stated in the previous post, the Buddhist solution to this problem -- nonduality -- is central to Buddhism's message. This sets it somewhat apart from Christianity, where "unity in multiplicity" is more a curiosity of God's nature than a central philosophical concern. Unity in multiplicity is not explicitly taught in Biblical doctrine, as far as I know, but many argue that it is implicit in it, at least in the notion of the Trinity, which some theologians have described as the "peri-choresis" ("around" - "dancing") of the Persons.
As I stated in an early letter to Hilston, order and coherence in the universe are accounted for in the Buddhist worldview by the radical interdependence of phenomena, the holism of reality, and the pervasive intelligence of Being known as buddhanature or rigpa (pristine cognitiveness). These aspects of reality also account for unity in multiplicity, as I will explain below.
According to Buddhist thought, reality is radically interdependent. Sometimes this interdependence is described as "emptiness," emphasizing the lack of inherent (independent) existence of objects; sometimes it is described as "continuity" (tantra), emphasizing the inseparability of all phenomena and the ultimate "wholeness," seamlessness, and completeness of reality. When Buddhists say that objects (including people) are "empty" or that they lack inherent existence, they don't mean that they don't exist at all, but rather that they exist dependently upon other objects. This interdependence is so complete that you cannot find a "bottom level" building block or ultimate "atom" of reality, out of which all other objects are built.
According to Buddhist teaching, this is not a negation of reality, but a precondition for its existence, for its manifestation. If any phenomenal object were self-existent, meaning completely self-contained and self-originated, complete in itself, it would be immutable and thus it could not interact with anything else or be in relationship with anything else. According to Buddhist thought, it is
because reality is interdependent that we have objective phenomena at all: a ceaseless flow of interactions and mutually determining relationships that gives rise to all manner of things, from atoms to organisms to galaxies.
Put more simply, the phenomenal world is fundamentally a relational world. Interdependence is the precondition for multiplicity, for the infinite textures of the universe that make up the different orders of being, from the subatomic to the macroscopic (and Buddhist scripture describes atoms about a third the size of the hydrogen atom and a cosmos several times larger than the one currently measured by science). But interdependence is also an expression of the oneness of reality, because all phenomena exist inseparably from one another.
The spiritual and moral significance of this relates to our apprehension of self-hood. We take ourselves to be independent entities, self-existent, self-contained, and in Buddhist thought this is one of the causes of our predicament and our "sin." We seek to "cut up" and "possess" what cannot be cut up or owned; we seek to grasp as "ours" what is only and always a "gift" of the totality.
Another aspect of "oneness" has to do with what Buddhism calls Buddhanature: the fundamentally open, creative, intelligent, dynamic ground of reality that is the root or essence of all phenomenal objects and beings. Dzogchen describes the phenomenal world as the "radiance" of this creative intelligence or Presence, an intelligence which does not exist as an object anyplace in space or time, but which is the root and essence of everything that appears.
Dzogchen describes reality as "the single sphere, unbounded wholeness," the nature of which is fundamentally creative and self-organizing. All of reality is the seamless movement of this boundless wholeness: open with infinite creative potential at its timeless root, ceaselessly manifesting in multiple interdependent forms as its time-like "activity."
I have run out of time this evening, but it's probably for the best. This was longer and more complex than I intended. I hope you can follow it; but I may come back and edit it later.
Peace,
Balder