The Highest Common Factor Heterodox Archaeology and the Perennialist Milieu Kevin A. Whitesides ABSTRACT: This article differentiates two universalist rhetorical strate- gies in common use among producers of alternative archaeological narratives: hyperdiffusionism and perennialism. Both strategies seek to account for perceived similarities in archaeological monuments world- wide by tracing them to a single ur-source. However, each takes a distinct epistemic position with respect to the identity of that source. Hyperdiffusionism and perennialism represent shifting ideological trends within the modern cultic milieu, and, therefore, noting the dis- tinction is important in tracing the reception history of archaeological monuments and artifacts. KEYWORDS: alternative archaeology, perennialism, hyperdiffusion, reception history, cultic milieu Monuments represent a variety of constantly changing meanings, determined by the light in which they are seen. People receive these monuments in the landscape by constructing an “imaginary world” around them, just like readers of a text con- struct an “imaginary universe” during the process of reading. ... People in different ages “constructed” monuments in their receptions in a way that made sense then, as part of distinctive “imaginary worlds”. ... In the perspective of such an archaeo- logical reception history, monuments such as megaliths are thus not merely of the 27 Nova Religio: The Journal of Alternative and Emergent Religions, Volume 22, Issue 4, pages 27–43. ISSN 1092-6690 (print), 1541-8480. (electronic).  2019 by The Regents of the University of California. All rights reserved. Please direct all requests for permission to photocopy or reproduce article content through the University of California Press’s Reprints and Permissions web page, https://www.ucpress.edu/journals/reprints- permissions. DOI: https://doi.org/10.1525/nr.2019.22.4.27.