One of these tools was the so-called Indice Categorico designed by Emanu-ele Tesauro. Tesauro displayed it as a ‘secret truly secret’ (‘secreto veramente secreto’), that is, as a truly valuable invention. According to Tesauro,72 the matter was to discover topics that were hidden behind several different cat-egories and to compare them to each other (‘penetrar gli obietti altamente ap-piattati sotto diverse Categorie, e di riscontrarli tra loro’) to discover analogies and similarities that would have otherwise been overlooked if everything had been preserved under its own category (‘scovare analogie e somiglianze che sarebbero passate inosservate se ogni cosa fosse rimasta classificata sotto la propria Categoria’). The cognitive device used to achieve this purpose was the metaphor. By listing topics in a jumbled manner under a certain category ac-cording to some similarity in meaning among them, it was possible to produce unexpected results. In short, it was possible to discover something new.