Analogy is analyzed as a process of implicit redefinition, which is based on the abstraction of a functional genus, i.e. a common generic property that is contextually essential for the purpose of the move. Based on the twofold genus-species relation and the corresponding topoi, the attributes of one of the terms of the analogy (the Analogue) are inherited by the generic concept and then transferred to the other subject (the Primary Subject). For this reason, this type of reasoning can be considered a strategy for introducing new implicit or explicit criteria of classification, which can result in the redefinition of an existing concept or the introduction of a new one. In the first case, new classification criteria expand the denotation of the analogue, thereby implicitly modifying its meaning. In the second case, a new definition is provided of a new implicit functional genus, under which the two different analogical concepts fall.