Original Article Review of General Psychology 2025, Vol. 0(0) 1–10 © The Author(s) 2025 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/10892680251390273 journals.sagepub.com/home/rgp Mind, Nature, and Religious Experience in William James and Carl Gustav Jung Luiz Henrique Santana 1, *  Abstract This paper examines how William James (1842–1910) and Carl Gustav Jung (1875–1961) developed fundamentally different philosophical frameworks for understanding consciousness, nature, and religious experience. Through close textual analysis of primary sources and engagement with recent historiographical debates, this study demonstrates that James’s evolution from “supernaturalist” phenomenology to religious naturalism grounded in radical empiricism differs fundamentally from Jung’s psycho-epistemological framework emphasizing archetypal structures. The analysis reveals how their divergent ontological commitments—James’s neutral monism versus Jung’s careful distinction between psychological and metaphysical reality—led to distinct methodological approaches to religious phenomena. James evaluated religious experiences pragmatically for their transformative “fruits,” while Jung interpreted them as symbolic expressions of individuation processes. These findings contribute to understanding how early psychology navigated between scientific materialism and religious phenomena, offering insights relevant to contemporary consciousness studies. Rather than imposing anachronistic categories, this historically grounded analysis clarifies both thinkers’ actual positions while exploring their enduring significance for psychology and philosophy of mind. Keywords William James, Carl Gustav Jung, religious naturalism, radical empiricism, neutral monism Introduction The emergence of scientific psychology in the late 19th century precipitated fundamental questions about the nature of consciousness and its relationship to religious experience. Among the most influential voices addressing these questions were William James and Carl Gustav Jung, whose divergent philosophical frameworks continue to shape contemporary debates in consciousness studies and the psychology of re- ligion. While both thinkers engaged seriously with phe- nomena that challenged the boundaries of conventional science—including their mutual interest in psychical research—their fundamental commitments led them to de- velop markedly different approaches to understanding mind, nature, and religious experience. This comparative analysis addresses a specific lack in scholarly literature by examining how James’s and Jung’s distinct ontological positions yielded divergent methodo- logical prescriptions for studying religious phenomena. The central argument advanced here is that James’s evolution toward religious naturalism, grounded in his radical empir- icism and neutral monism, produced a pragmatic method- ology that evaluated religious experiences by their transformative effects while maintaining openness to their potential validity as encounters with reality’s deeper di- mensions. In contrast, Jung’s psycho-epistemological framework, which carefully distinguished psychological from metaphysical claims, led to an interpretive methodology that treated religious experiences as symbolically meaningful expressions of individuation processes rather than potential contacts with transcendent reality. The significance of this comparison extends beyond historical interest. As contemporary consciousness studies grapple with the “hard problem” of consciousness (Chalmers, 1995) and cognitive science increasingly engages with re- ligious phenomena (Boyer, 2001), understanding how these pioneering psychologists navigated similar 1 Department of Psychology, Faculdade de Ci ˆ encias M´ edicas da Santa Casa de São Paulo, Brazil *Current affiliation: Graduate Program in Health Psychology, Department of Health, Universidade Metodista de São Paulo, Brazil Corresponding Author: Luiz Henrique Santana, Department of Psychology, Faculdade de Ci ˆ encias M´ edicas da Santa Casa de São Paulo, Rua Dr Ces´ ario Mota J´ unior, 61, Vila Buarque, São Paulo 01221-020, Brazil. Email: santana.lhc@gmail.com