Cosmos and Psyche, a 2006 book by cultural historian Richard Tarnas, posits a connection between the movements of planets and significant historical and cultural occurrences. Tarnas suggests that planetary transits are not direct causes of events but rather indicators of the archetypal dynamics present at a given time. He challenges the materialistic worldview prevalent in modern thought, arguing for a participatory epistemology where humanity is integral to the unfolding of reality. The book draws inspiration from the Uranus-Pluto conjunction during the 1960s cultural revolution and a similar alignment during the French Revolution, noting shared themes of suppressed forces manifesting. Tarnas extends this analysis to other pivotal periods like the Renaissance and the Reformation, examining biographical correspondences with figures such as Nietzsche and Blake. He employs C.G. Jung's concept of synchronicity to support the idea of acausal connections between the external world and the human psyche.

Richard Tarnas's Cosmos and Psyche aims to counter the materialistic and teleological assumptions of contemporary thought. The book presents evidence suggesting a correlation between celestial alignments and the patterns observed in human history. Tarnas proposes an archetypal cosmology that aligns with a participatory epistemology, viewing humans as essential participants in the self-unfolding of existence. This perspective challenges the notion of a purely mechanistic universe, suggesting instead a more ensouled and interconnected reality.

A key impetus for Cosmos and Psyche was Tarnas's observation of the Uranus-Pluto conjunction coinciding with the 1960s cultural revolution. He noted similar Uranus-Pluto dynamics in the French Revolution, both periods marked by revolutionary change and the emergence of repressed elements. Tarnas's research, which does not find significant correlations with zodiac signs, focuses on the outer planets' major aspects (conjunctions, oppositions, squares) and their potential resonance with pivotal moments in Western history, including the Reformation, Renaissance, and Romanticism. He uses C.G. Jung's concept of synchronicity to frame these connections as meaningful, acausal correspondences between the cosmos and human affairs.

The book received varied critical responses. Some reviewers, like Esther Fields and Frederick Dennehy, praised Tarnas for challenging modern assumptions and offering a new cosmic perspective, suggesting the work pointed toward significant world changes. Others, such as Thomas Meaney, were highly critical, dismissing the premise as unfounded. Astrologer Neil Spencer favorably contrasted Tarnas's work with materialistic viewpoints, seeing it as an attempt to 're-enchant' the cosmos. Daniel Pinchbeck described the book as meticulously researched and argued, advancing a radical thesis to elevate astrology as an intellectual discipline and provide a cosmological link between humanity and the universe.