2. Kant's Criticism and the Chain of Being.
In the
Allgemeine Naturgeschichte und Theorie des
Himmels
(1755), Kant takes up the Leibnizian argument of the
coincidence in God of the possible and the actual:
creation is surely
commensurate with the power of an
infinite being, and it would be nonsense
to say that
God allows only a minimal part of his creative poten-
tial to pass into actuality. It is more
reasonable to
suppose that divine creativity does not unfold all at
once but gradually, that creation has indeed a begin-
ning but no end. In the formation of worlds, the first
elements
of chaos already bear the signs of that com-
pleteness that is of the very nature of their origin, since
their nature can only be a consequence of the eternal
idea of the divine
intelligence. Matter itself has within
it the tendency to organize itself,
through natural
evolution, in always more perfect forms.
Here, as we see, Kant gives us what Lovejoy ([1936],
Ch. IX) later called a
“temporalized” version of the
Chain of Being, in
which creation takes the form of
a natural development starting from the
divine idea;
and it comes about step by step, filling up space with
worlds in the process of eternity. It is an evolutional
ebb and flow in
which worlds are formed and dissolved;
but the production of ever new
worlds guarantees the
fullness and infinite variety of the whole. If in
its
temporal variations a system exhausts all the variety
of which it is constitutionally capable, it becomes a
useless
member of the Chain of Being, and so performs
its last act in the
vicissitudes of cosmic change, paying
its tribute to mortality.
The problem of the Chain of Being is taken up in
very different terms in the
Critique of Pure Reason
(1781), and precisely in
the Appendix to the Transcen-
dental
Dialectic. Here Kant examines the principles
of plenitude and continuity
still operative in the sci-
ences of the time,
in order to reduce them to “ideas
of the Reason”
(transcendental ideas), which as such
have no
“constitutive” use but a purely
“regulative”
one, that is to say, they are capable of
directing the
Understanding to a certain aim, conferring upon its
concepts the greatest unity and extension. Even lying
quite outside the
limits of possible experience, the ideas
of the Reason constitute the
systematic unity of knowl-
edge. By virtue of
this “transcendental presupposition”
we may assume a
homogeneity in the apparent infinite
diversity of nature, a unity of its
fundamental proper-
ties. This is the
scholastic principle of Ockham, “enti-
ties are not to be multiplied more than are necessary”
(entia praeter necessitatem non esse
multiplicanda); and
it is the foundation of logical
classification. Beside this
principle, which Kant calls the
“principle of homo-
geneity,” and which allows the reduction of the various
species to subsumption in a few genera, also at work
in the reason is the
“principle of specification,” which
requires a
multiplicity and difference among things in
spite of their grouping in a
same genus. Each genus
requires diverse species, and each species diverse
sub-
species; and
as none even of these subspecies is without a sphere...
reason in
all its extension requires that no species should
in itself be
considered as the lowest, since the species being
always a concept
containing only that which is common
to different things,... it
must always subsume other con-
cepts or
subspecies. This principle of specification might
be formulated
thus: entium varietates non temere esse minu-
endas
(“the variety of things is not to be
minimized”).
What Kant calls the law of specification is precisely
the principle of
plenitude. Inasmuch as it is an ideal
of the reason it cannot be inferred
from experience,
since empirical specification goes no farther than ob-
servable multiplicity; but it is a
regulative principle
of experience, since it invites reason to seek the
“dis-
tinctive and to
presuppose it ever anew, although not
immediately manifest to the
senses.” From the two
foregoing
principles—homogeneity and plenitude—
there also
arises the principle of the continuity of
forms, which provides a
continuous transition from
species to species by means of a gradual
building up
of differences. Since
... there is no void in the entire sphere of all possible
concepts, and
as nothing can be discovered outside this
sphere, there arises the
principle non datur vacuum for-
marum, that is to say, there are no
different original and
first genera, isolated and separated from each
other, as it
were by an intervening void, but all the different
genera
are divisions of only one supreme and general genus. From
that principle springs its immediate consequence, datur
continuum formarum, that is, all the differences
of species
border upon one another and admit of no transition from
one to another per saltum.... This logical law
of the
continuum of species (continuum
specierum) presupposes a
law of continuity in nature
(lex continui in natura), which
however remains only thinkable, not knowable: This conti-
nuity of forms is a mere idea, for which it is not
possible
to find a corresponding object in experience, not only be-
cause the species in nature are actually
divided, and must
form, each by itself, a discrete quantity (quantum dis-
cretum),... but also because we can make no
determinate
empirical use of this law, since it does not offer the
least
criterion to tell us how and how far we ought to seek for
different grades of affinity; the law of continuity tells us
only in
general that we ought to seek for them....
In short, there is no empirical use of the principle of
continuity;
it has only a regulative use: as simply an
idea, it serves only to alert us
in general that a series
should be sought in nature.
The same can be said, Kant goes on, of the “famous
law” of the Scale of Creatures, consequence of the two
principles in question. The notion of a Chain of Being
is not objectively
verifiable by observing nature: “the
steps of this scale, so far
as we are able to know them
by experience, are much too far apart, and the
(puta-
tively) small differences in
nature itself are ordinarily
crevices so vast, that such observations
cannot be relied
upon.... ” Even the idea of a Chain of Being,
then,
is a regulative principle only, a “method”
according
to which we seek order in nature—but a method
that
“goes too far for experience or observation to
match.”
Thus the Chain of Being is reduced, in Kant, to one
of those ideals for
which there is no empirical appli-
cation,
and which indeed, in their empirical use, can
produce only imaginary
knowledge and hence eternal
contrasts and contradictions. And with that an
essential
aspect of the Chain of Being is wanting: its function,
namely, as a scheme of nature that observation is
supposed to fill in
gradually by reconstructing it em-
pirically. Such a reconstruction, for Kant, is not possi-
ble: it would indeed constitute an example of the
dialectic of appearance. In these same decades, and
no doubt independently
of the Kantian criticism, the
biological sciences produced a profound
transformation
in the idea of a Chain of Being; and at the end of
this
process the conclusion emerges that it is impossible
to reconstruct in a
scientific way the hierarchical
structure of the universe. In this way that fixed struc-
ture loses all objective validity and is
no longer one
of the constitutive principles of scientific research.
