One or several trees? Visual metaphors and taxonomies

This paper addresses Umberto Eco’s critique of how traditional semantic models em-ploy the metaphor of the tree to describe the taxonomic structure of language. Eco’s theory of unlimited semiosis is based on the comparison between two conceptions of the organization of semantic knowledge, the dictionary and the encyclopaedia. They are considered not only two distinct methods of storing information but also approaches to text interpretation. The dictionary is a closed system structured like a hierarchical tree of knowledge that organises lexemes in genera and species, which derives from Porphyry’s tree, while the encyclopaedia is a multidimensional network in which the connection between lexemes is not predetermined. Starting from these two models Eco elaborates a theory of metaphor that contrasts with the traditional view of substitution and supports the idea of metaphor as a “condensation” whose goal is to extend the already existing categorizations, rather than confirming them. My aim is to point out how Eco uses the “semantic tension” of metaphors as the basis for a critique of the taxonomic tree and to sketch a new form of organization of semantic structures. Nevertheless, the metaphor of the tree is not completely abandoned by Eco. It is reinterpreted as a provisional map to build a tentative categorization to find orientation in the labyrinth of all possible text interpretations.