"The tree of knowledge" & knowledge trees

A metaphor used about the organization of human knowledge. Among the most known users of this metaphor are:


"Perhaps it is useful to notice that there are three different metaphorical trees. The oldest one is the Tree of Knowledge from Genesis 2,9. Philosophers, however, are better acquainted with the Tree of Porphyry: the tree of genus and species, born in the Fifteenth century, discussed by medieval logicians and often represented in Medieval and Renaissance books of logic. Both trees are mentioned in Peirce's Collected Papers (CP 3.488, 2.391 and 5.500), and on the latter one he wrote the entry for the Baldwin's Dictionary. But neither one is the tree I want to refer to. The tree that has my preference is the Arbor Scientiae which was made fashionable by Ramon Lull in the XIIIth century and which for many centuries has been the most common metaphor of the genealogy of sciences. According to this metaphor, all sciences are begotten from the common trunk of philosophy, which provides their underlying unity. The metaphor survives until now in the common usage of the expression "branches" to refer to the different areas of science." (Nubiola, 1998, [5]).




Tree of Porphyry drawn by Peter of Spain (1329)



Deleuze & Guattari (1987) criticizes the three model and suggests the rhizome as an alternative:


"Deleuze and Guattari [1987] make no bones about the fact that they oppose the root-tree model. They see it as a model of totalizing theory, a model that's specifically designed to function as a restrictive stratum, imposing its forms on a maximum of flows, particles, and intensities. They make their case quite clearly:
    We're tired of trees. We should stop believing in trees, roots, and radicles. They've made us suffer too much. All of arborescent culture is founded on them, from biology to linguistics. (17)
In opposition to the root-tree model, D & G offer the rhizome, a structure without a centralized, hierarchical organization, a structure that, in many ways, reflects the more "natural" pattern of geo-organic development. They say, "Many people have trees growing in their heads, but the brain is more like a grass than a tree" (17). We're taught to act like trees and forced to think like trees, but D & G believe that we more "naturally" think like rhizomes (grass not trees)." (Taylor, 1996).



What may still be possible is to shake up the Tree of Knowledge. As an armature for classifying ideas, a tree is a rigid structure. Its definitive feature is that branches diverge but never rejoin, so that every node can have but one parent. The proliferation of portmanteau disciplines—astrophysics, biochemistry and so on—suggests that this single-parent principle is under strain. Perhaps we should replace the tree with a matrix: Given n "prime" sciences labeling the columns and rows, we'd have cubby-holes for n 2 combinations. On a campus built to reflect this architecture, you could always find your department by locating the intersection of the appropriate streets. ("Meet me at the corner of Bio and Soc.") (Hayes, 2004).




In relation to the tree of knowledge is the root-tree metaphor. This is very influential in ordinary thinking, when we speak about "going to the root of the problem" or say that something is the root of research, e.g. "Genomic DNA: The root of all molecular genetic research".





Deleuze, G. & Guattari, F. (1987). A Thousand Plateaus. Capitalism and Schizophrenia. Translation and foreword by Brian Massumi. Minneapolis: University of Minnesota Press.


Hayes, B. (2004). Undisciplined science. Is the Tree of Knowledge an outdated metaphor? American Scientist, 92(4), 306-310. Available at:  http://www.americanscientist.org/template/AssetDetail/assetid/34142


Kazlev, M. A. (1999). The world tree. http://www.kheper.net/integral/tree.html

Maturana, H. & Varela, F. (1987). The Tree of Knowledge: The Biological Roots of Human Understanding. Boston: Shambhala Publications Inc.


Nubiola, J. (1998). The branching of science according to C. S. Peirce. Originally presented at the 10th International Congress of Logic, Methodology and Philosophy of Science August 22, 1995, Florence, Italy. Available at:  http://members.door.net/arisbe/menu/library/aboutcsp/nubiola/branch.htm


Peirce, C. S., 1931-35, 1958. The Collected Papers of C. S. Peirce. Harvard Uni. Press. Vols. 1-6 edited by Charles Hartshorne and Paul Weiss; Arthur Burks edited Vols. 7,8. Vol. 1 available online at: http://www.textlog.de/peirce_principles.html


Taylor, A. (1996). Mus(e)ings on Deleuze & Guattari. Wanderings and reflections. A collection of short essays concerning the works of Gilles Deleuze & Felix Guattari and their relevance to the study of rhetoric.  http://www.uta.edu/english/apt/d&g/arhizome.html


Walker, T. D. (1996). Medieval faceted knowledge of classification: Ramon Llull's trees of science. Knowledge Organization, 23(4), 199-205.


Wikipedia. Die freie Encyklopâdie. (2005). Baum des Wissens. http://de.wikipedia.org/wiki/Baum_des_Wissens


Yager, R. R. (2006). Knowledge trees and protoforms in question-answering systems. Journal of the American Society for Information Science and Technology Published Online: 18 Jan 2006

Tree of Life: http://tolweb.org/tree/phylogeny.html



See also: Atlas of Science; Classification of the sciences




Birger Hjørland

Last edited: 28-02-2007