I
1. The Ontological Basis for the Gradation of Ex-
isting Things.
Historically we may trace the concep-
tion of a Chain of Being to the Platonic Idea of Ideas,
or Idea of the Good, discussed in the seventh book of
the Republic. This Idea is in fact the summit of the
hierarchy of knowable things, for not only do they owe
to it the quality of
their being knowable, but derive
from it their very, existence by
participating in various
degrees in its nature (509b). Thus, the supreme
Idea
provides the logical basis of a world of sensibilia con-
ceived as graded with respect to
perfection. The Idea
of the Good, however, is no more than a logical foun-
dation, insofar as no active element or
agent intervenes
yet; instead, this element of activity is made an
intrinsic
feature of the Demiurge, introduced by Plato in the
Timaeus. The Demiurge creates the sensible world
modelled on the intelligible one (27d-29c). He cannot
fail to generate
things in that way since, being with-
out
jealousy, his very nature is to desire that all things
approach as closely
as possible to himself (29d-30a).
Fecundity is thus an essential element of
divine per-
fection. Self-sufficient
perfection is at the same time
self-transcendence in the sensible world.
Thus God
becomes at once the logical and ontological foundation
of the
world's multiplicity and variety.
This quality of generative self-transcendence of the
supreme Being finds its
most radical expression in
Plotinus. It is of the very nature of the One in
its
perfection to “overflow,” producing in its
exuberance
the “other” (Enneads V, 21). All beings, then, partici-
pate in the nature of the Good in such measure as they
may,
according to their individual capacity.
2. The Chain of Being as a “plenum
formarum” or
Plenitude of Forms.
It is again in the Timaeus that we
must seek
the source of what Lovejoy has called the
“principle of
plenitude”: the idea that in passing from
the eternal order to
the temporal, from the ideal to
the sensible, there must be realized a
fullness of forms
in which every possible form becomes actual. If crea-
tivity is essential to the very
perfection of the supreme
Being, existence cannot be begrudged any manner
of
things, whatever their grade of perfection. Moreover,
the supreme
Being creates after the likeness of an
intelligible model: for every idea
there must be a
corresponding perceptible object; every possibility
will
have its corresponding reality.
It follows—and Plotinus draws this consequence in
all its
import—that the divine self-transcendence, or
inexhaustible
power of the One, must in its creative
necessity reach the extreme limits
of the possible.
There is a kind of chain of delegated productive
powers: every hypostasis in this generative scale is
involved in this
productive necessity, and its creativity
must proceed out of itself to the
extreme limit of the
possible. Nothing may be barred from existence,
which
is to say, from more or less participation in the nature
of the
Good (Enneads IV, 8, 6).
What is full obviously cannot admit any discon-
tinuity. Thus in the Chain of Being the principle of
continuity
is associated with the principle of fullness
and is often confused with the
latter. Aristotle had
already observed that in the world of living things
the
different orders overlap. In the classification of animals
according to habitat—terrestrial animals, animals in-
habiting air and water—there are
many intermediate
forms irreducible to one or another of these
classes.
The passage from the inanimate to the animate is so
gradual
that continuity makes the boundary between
the two orders imperceptible. It
is the same for the
passage from the order of plants to that of
animals,
so that for many living forms it is hard to establish
to
which of the two classes they belong (Aristotle,
History of Animals VII. 1. 588b).
It is easy to see that such considerations should have
reinforced the
principle of plenitude—even though this
was not authorized by
the Aristotelian teaching on
potentiality and actuality, according to which
there
do exist possibilities which have not yet come into
existence
(Metaphysics III. 1003e 2; XII. 1071b 13).
