In the 19th century, the study of the nature of knowledge came to be known as epistemology. The term was introduced by Scottish metaphysic James Frederick Ferrier (1808-1864).









Epistemological writers explored how knowledge relates to connected notions, such as belief and truth. They also considered the means of production of knowledge. And to a large extent, they embraced skepticism. a mode of thinking that required information to be well supported by evidence before it could be accepted as fact, i.e., knowledge.

Here we see how philosophy and science were developing hand in hand. This continued into the 20th century. The study of knowledge broadened in response to understandings contributed by psychology (especially in memory and perception), library science, linguistics, and computer science. Information science became a separate field, covering such things as linguistic analysis and vocabulary control.

But I digress. Speaking of library science, let’s go back to the 19th century, which saw the rise of classification.

As far as I’m concerned, the hero of classification systems is Charles Ammi Cutter (1837-1903).








As a librarian at Harvard College, Cutter invented the card catalog. (Before that, library holdings were listed in published books. Yuck.) His system used an author index, and a “class catalog”, or subject index. Here we see the beginnings of modern approaches to subject matter classification.

Later, influenced by the decimal system of Melvil Dewey, Cutter came up with the Cutter Expansive Classification system. It had seven levels of classification, each with increasing specificity. However, you could use the lower levels and still be specific.

According to library historian Leo E. LaMontagne, “Cutter produced the best classification of the nineteenth century. [Its] key features – notation, specificity, and versatility – make it deserving of the praise it has received.” Unfortunately, Cutter died before he could finish his classification system. However, it is still used by many small libraries, and it served as a foundation for the Library of Congress subject headings.

Proof that Cutter was a forward-looking thinker can be found in his article, “The Boston Public Library in 1983” (no, that’s not a typo), published in 1883. Here’s one of Cutter’s predictions that appeared in the article:

“The desks had every convenience that could facilitate study; but what most caught my eye was a little key-board at each, connected by a wire with the librarian’s desk. The reader had only to find the mark of his book in the catalog, touch a few lettered or numbered keys, and on the instant a runner at the central desk started for the volume, and, appearing after an astonishingly short interval at the door nearest his desk, brought him his book and took his acknowledgment without disturbing any of the neighboring readers.”

Of course, we can’t forget Melvil Dewey (1851-1931), inventor of the Dewey Decimal Classification (or, if you prefer, the Dewey Decimal System).









I think most of us are already familiar with the DDC. Or you might know of the Universal Decimal Classification, which is based on the DDC.

So what’s so great about the DDC? Someone asked that very question in 2006. The query continued,

“It seems obvious that if you have to categorize a huge number of objects (say, books for example), you would set up a set of unique categories, sort the objects into the appropriate category, and then itemize the objects within that category. Is Dewey famous just because it’s the standard, or is there more to the system that makes it so great?”

Dex, of The Straight Dope, answered, in part:

“What’s obvious to you, the jaded library patron, wasn’t so obvious in the era before Melvil Dewey. Once a creative genius comes up with an innovation, a century later everyone thinks it’s obvious. If you think it’s so easy, you come up with a system for classifying all knowledge that ever was and ever will be.”


Marjorie M.K. Hlava, President, Access Innovations

Note: The above posting is one of a series based on a presentation, The Theory of Knowledge, given at the Data Harmony Users Group meeting in February of 2011. The presentation covered the theory of knowledge as it relates to search and taxonomies.