This article presents an unpublished lecture by Francisco Fern & aacute;ndez Buey (1943-2012), a prominent member of the Barcelona Marxist school and disciple of Manuel Sacrist & aacute;n. On the one hand, the author focuses on examining the improper uses of the notion of dialectics, rejecting its con-ception as an alternative logic to formal logic, as a science or as a method in the strict sense. On the other hand, he shows a characterisation of dialectics as a << methodic >> in a broad sense that aims to grasp concrete totalities in their unfolding from a materialist, historical and critical point of view, with emancipatory aims, whose scientificity could only be admitted if it is under-stood in a subordinate sense