Rafael Capurro, in a paper entitled Epistemologia e Ciência da Informação (2003), presented at the V ENANCIB – Encontro Nacional de Pesquisa em Pós-Graduação em Ciência da Informação (Belo Horizonte, Brazil) put forward an innovative proposal for information science, which defended the existence of four paradigms and condensed and illustrated the evolution of documentation/information science by Paul Otlet This contribution inspired the authors of this text—who had already formulated an initial approach that established three phases (syncretic, custodial and post-custodial), while pursuing a different path and situated in the Portuguese context, to observe two paradigms: the custodial, historicist, patrimonial and technical (between the 18th and mid-20th century) and the post-custodial, informational and scientific (from the mid-20th century) This paper aims to establish a constructive and critical confrontation of Capurro and Izquierdo Arroyo's proposals that are rooted in different but complementary epistemological conceptions