386

31

The Organization of Knowledge

conclusions or suggest new relationships. The World Wide Web Consortium (W3C)

has released a number of standards and specifications for the Semantic Web, and the

number of Semantic Web tools and applications is increasing.

Problem. Discuss whether the kind of conclusions delivered by the Semantic Web

are purely deductive and, hence, comprise knowledge already present in the data.

Problem. Machines can now be programmed to understand and interpret natural

language, allowing them to “understand” commands (in the sense that they correctly

execure them), enhancing interaction with human beings. Discuss whether this field

of activity is a legitimate branch of bioinformatics.

31.2

The Classification of Knowledge

We have already mentioned Linnaeus’ Systema Naturae; the first tree of knowledge

was devised by Porphyry about 1800 years ago. The tree appears again at the end of

the thirteenth century in Llull’s Arbre de ciència, and explicitly used as a metaphor

for the unity of knowledge by Descartes in the 17th century, and by Diderot and

d’Alembert in the 18th for their Encyclopédie. ⁷ By the nineteenth century the expo-

nential growth of knowledge made mapping of accumulated knowledge essential

to further growth. The problem was concretized in the need to rationally arrange

books in libraries, which led to discipline-based systems like Dewey’s decimal clas-

sification, Universal Decimal Classification (UDC), and the Physics and Astronomy

Classification Scheme (PACS) used by some journals.

In the twentieth century, the Indian mathematician Shiyali Ranganathan intro-

duced the “facet” concept: expressing the subject of a document by analysing it into

“facets”, and using connective operators to construct class numbers from the facets

for every conceivable subject. ⁸ His classification can be seen as the mapping of a

multidimensional universe of subjects along a line, according to a set of rules. To

avoid being overwhelmed by vast numbers of individual ideas, he proposed identify-

ing relations among them until a few “fundamental categories” are reached. ⁹ Unlike

the traditional classifications that use predetermined disciplines and proceed “top–

down”, a document’s facets are first analysed and then synthesized to produce “main

subjects”; i.e., a “bottom–up” procedure.

7 See Alfonso-Goldfarb et al. (2012) for a much fuller account.

8 Ranganathan (1937).

9 Ranganathan considered five: personality, matter, energy, space and time; note the absence of

information (but perhaps this is what personality is).