“Mapping 18th Century Structures of Knowledge: the
Renvois System in Diderot's Encyclopédie”
Gilles
Blanchard
Ecole Normale Supérieure, France
Mark
Olsen
University of Chicago, USA
One of the crowning achievements of the 18th century Enlightenment was the Encyclopédie ou Dictionnaire raisonné des sciences, des arts et des
métiers, par une Société de Gens de lettres, edited by Diderot and
d'Alembert. Published in Paris between 1751 and 1772, in 17 volumes of text and 11
volumes of plates, it contains 74,000 articles written by more than 140
contributors. The Encyclopédie was a massive reference work
for the arts and sciences, as well as a machine de
guerre which served to propagate Enlightened ideas. The impact of the
Encyclopédie was enormous. Through its attempt to
classify learning and to open all domains of human activity to its readers, the
Encyclopédie gave expression to many of the most
important intellectual and social developments of its time.
The scale and ambition of the Encyclopédie inspired the
editors to adopt three modes of organization: dictionary, encyclopedic, and the
renvois. The interaction of these three modes has
led modern scholars to describe the Encyclopédie as the
"ancestor of hypertext" and depict Diderot as "l'internaute d'hier"°. Diderot makes the
importance of the organization of knowledge explicit in the Discours Preliminaire:
“As an Encyclopedia, it is to set forth the
order and connection of the parts of human knowledge. As a Reasoned Dictionary of the Sciences, Arts, and
Trades, it is to contain the general principles that form the
basis of each science and each art ... and the most essential facts that
make up the body and substance of each.”
°
Of the three modes of organization, the dictionary mode (organization of entries in
alphabetical order) is certainly the simplest. The second mode of organization is
encyclopedic, where each entry is assigned a "class of knowledge", placing it within
the "order" of human knowledge, as was described by d'Alembert's Systême Figuré des connoissances humaines. Reflecting Enlightenment
theories of epistemology, the tree of knowledge has a three-fold trunk comprised of
memory, reason, and imagination, from which spring many branches, twigs, and leaves
(Image of Pank's tree). Simply placing an entry into this hierarchy of knowledge was
insufficient to indicate the inter-connections of knowledge. Thus, Diderot created
an extensive system of renvois (cross-references), the
third mode of organization, providing a lattice of inter-connections between
individual leaves of the tree as well as between classes of knowledge. The reader is
encouraged to follow the renvois, which unite fields of
knowledge into what was hoped to be a seamless totality.
The ARTFL Project's creation of a computer implementation of the Enlightenment's "war
machine"° has attempted to provide this three-fold access and navigation to
scholars and researchers. Furthermore, the electronic Encyclopédie provides a unique tool to study the interactions of these
three modes of organization of knowledge. Systematic examination of Diderot's
hypertext is important not only for the light it sheds on the function and
construction of the Encyclopédie itself and the contours of
18th century knowledge, but may also be informative for modern conceptions of
hypertext.
The two first modes of organization (dictionary order and encyclopedic classification
of knowledge) can be envisioned directly by the reader of the Encyclopédie. The third, the structure of the renvois, is impossible to grasp as a whole because of its more diffuse
nature. The 61,700 individual renvois are unevenly
distributed across the 74,000 articles of the Encyclopédie,
reflecting the wide variation in size and scope of articles. 22,955 articles or
subarticles have one or more renvois. As might be
expected, articles with renvois are significantly longer
(568 words) than those without (158 words). The renvois
simply refer to one or more articles by head word. Thus, these connections are what
might be termed leaf to leaf (or node to node), which allow the user to traverse
leaves, without regard to the classes of knowledge. As a reader, one can only see
the links stemming locally from a particular entry: much as someone hiking in a
chain of mountains, it is not possible to step back and get a general vision of the
whole landscape.
The online version of the Encyclopédie allows us to draw a
very coarse first map of the links "landscape". Our methodology was to group the
entries into the classes of knowledge to which they belong and to measure the
strength of relationships of all of the renvois between
these classes of knowledge using a simple Z-score calculation. The resulting graph
shows the statistically significant (or "privileged") links between classes of
knowledge. A given renvois does not specify a precise
sense of the word we should look for, and for any given word one often finds several
distinct entries corresponding to different classes of knowledge (polysemy). There
is no automatic way to determine the "true" link initially intended by the author -
assuming that the author had a single sense in mind. However, a statistical study
taking into account several independant renvois between
classes allows us to get a more reliable picture and to disregard insignificant
links.
The encyclopedic landscape shows some striking features. First, there is a high local
connectivity between close classes - in other words, there are several different
ways to go from "physique" to "géometrie", for example. Secondly we can see a clear
division of the links landscape into two "hemispheres", namely, knowledge related to
direct observation of nature (histoire naturelle), heuristic sciences (chimie,
médecine), rural life (économie rustique) on the one hand; and knowledge related to
or contructed by the human mind on the other (abstract sciences such as mathematics;
philosophy; history; laws of human society). Not surprisingly, the "human
hemisphere" is much more important than the "natural hemisphere" in terms of sheer
size.
The general structure of the renvois can be related to
the encyclopedic order pictured in d'Alembert's Systême
Figuré. For example, mathematics, geometry, and arithmetic are closely
grouped in our landcape drawn from the renvois and in
the encyclopedic order defined by d'Alembert. The two hemispheres detected in this
preliminary examination, however, do not clearly correspond to d'Alembert's general
schema. The power of the Encyclopédie's "hypertextuality" arises from the
combination of a general map of the structures of knowledge and the lattice of
related cross-references. Rather than conceive of the renvois as simply node to node
links, Diderot's hypertext assumes an abstract representation of knowledge. He
writes, in the Discours Préliminaire,
“On a tâché que l'exactitude & la fréquence des renvois ne laissât là - dessus rien à desirer; car les renvois dans ce Dictionnaire ont cela de
particulier, qu'ils servent principalement à indiquer la liaison des
matieres; au lieu que dans les autres ouvrages de cette espece, ils ne sont
destinés qu'à expliquer un article par un autre. [...] Ainsi trois choses
forment l'ordre encyclopédique; le nom de la Science à laquelle l'article
appartient; le rang de cette Science dans l'Arbre; la liaison de l'article
avec d'autres dans la même Science ou dans une Science différente; liaison
indiquée par les renvois...”
°
The key role that abstract representation of knowledge plays in the construction of
Diderot's hypertext may be particularly instructive for current hypertext designers.
In addition to node to node links, hypertext design may be enhanced by working
within the context of organizational framework such as Diderot's representation of
classes of knowledge.