Since Spengler borrowed from the mineralogical terminology the term "pseudomorphism" to apply it to the morphology of cultures and to the interpretation of the relationship between different cultural traditions, this concept has widely been used in the vocabulary of philosophy and human sciences. This article intends to reconstruct some milestones in the history of the effects of such a loan, while investigating the oscillations of its semantic spectrum and its methodological and epistemological implications. Spengler employed the concept in a negative sense, to describe a phenomenon of morphological constraint: a new culture is compelled by the inertial force of a previous culture to take on alien forms to express its own contents. Among Spengler's readers, Jonas had recourse to the notion of "pseudomorphosis" in order to explore the links between the Gnosis and the Greek, Oriental and Christian traditions; Mumford used it to analyse the connections between recent technological inventions and the old forms of power and economy; Adorno conceived pseudomorphosis as a pernicious mimesis (philosophy mimicking sciences; art imitating the conceptual language; music imitating painting). All share the idea that pseudomorphism consists of a false manifestation of form, which ends up masking the expression of an authentic and original content. Moreover, the adoption of old forms to communicate new contents encourages merely superficial and largely unfounded analogies and similarities. Panofsky also adopts the notion in his iconology, impressing however to the concept different semantic nuances at different moments of his work. In Studies of Iconology (1939) he recognizes the heuristic value of pseudomorphism, which is capable of bringing to expression, during the Renaissance, contents that had remained unexpressed in ancient times thanks to the mediation of surviving medieval elements: a complex articulation of the pseudomorphic function in three times, that highlights a poietic retroactive movement exerted by the present on the remote past thanks to the metabolic activity of the recent past, in the wake of Warburg's investigations on the Nachleben der Antike. Such acknowledgment is however lost in the subsequent reflections: in Tomb Sculpture (1964) Panofsky reaffirms the negative and simplistic sense of pseudomorphism as an apparent but groundless formal analogy. Taken in this pejorative sense, the term is assumed by art historians like Rosenblum and Bois. But the revaluation, in recent times, of the phenomena of anachronism (Didi-Huberman, Nagel, Wood, Powell) is promoting a new sensibility for the heuristic potentials of the pseudomorphic retroaction. To be fully accomplished, this requalification must be accompanied by a coherent theory of similarities.
