This paper examines the experience of where we end and the rest of the world begins, that is, the sense of boundaries. Since meditators are recognized for their ability to introspect about the bodily level of experience, and in particular about their sense of boundaries, 27 senior meditators (those with more than 10, 000 hours of experience) were interviewed for this study. The main conclusions of this paper are that (a) the boundaries of the so-called “physical body” (body-as-object) are not equivalent to the individual’s sense of boundaries; (b) the sense of boundaries depends upon sensory activity; (c) the sense of boundaries should be defined according to its level of flexibility; (d) the sense of body ownership (the sense that it is one’s own body that undergoes an experience) cannot be reduced to the sense of boundaries; nevertheless, (e) the sense of ownership depends on the level of flexibility of the sense of boundaries.

Key words: boundaries, mindfulness, sense of boundaries, sense of ownership.

This paper discusses the phenomenological nature of the sense of boundaries (SB), based on the case of S, who has practiced mindfulness in the Satipathana and Theravada Vipassana traditions for about 40years and accumulated around 20,000h of meditative practice. S’s unique abilities enable him to describe his inner lived experience with great precision and clarity. S was asked to shift between three different stages: (a) the default state, (b) the dissolving of the SB, and (c) the disappearance of the SB. Based on his descriptions, we identified seven categories (with some overlap) that alter during the shifts between these stages, including the senses of: (1) internal versus external, (2) time, (3) location, (4) self, (5) agency (control), (6) ownership, and (7) center (first-person-egocentric-bodily perspective). Two other categories, the touching/touched structure and one’s bodily feelings, do not fade away completely even when the sense-of-boundaries disappears.

This paper is a practical guide to neurophenomenology. Varela’s neurophenomenological research program (NRP) aspires to bridge the gap between, and integrate, first-person (1P) and third-person (3P) approaches to understanding the mind. It does so by suggesting a methodological framework allowing these two irreducible phenomenal domains to relate and reciprocally support the investigation of one another. While highly appealing theoretically, neurophenomenology invites researchers to a challenging methodological endeavor. Based on our experience with empirical neurophenomenological implementation, we offer practical clarifications and insights learnt along the way. In the first part of the paper, we outline the theoretical principles of the NRP and briefly present the field of 1P research. We speak to the importance of phenomenological training and outline the utility of cooperating with meditators as skilled participants. We suggest that 1P accounts of subjective experience can be placed on a complexity continuum ranging between thick and thin phenomenology, highlighting the tension and trade-off inherent to the neurophenomenological attempt to naturalize phenomenology. We then outline a typology of bridges, which create mutual constraints between 1P and 3P approaches, and argue for the utility of alternating between the bridges depending on the available experimental resources, domain of interest and level of sought articulation. In the second part of the paper, we demonstrate how the theory can be put into practice by describing a decade of neurophenomenological studies investigating the sense of self with increasing focus on its embodied, and minimal, aspects. These aspects are accessed via the dissolution of the sense-of-boundaries, shedding new light on the multi-dimensionality and flexibility of embodied selfhood. We emphasize the evolving neurophenomenological dialogue, showing how consecutive studies, placed differently on the thin-to-thick 1P continuum, advance the research project by using the bridging principles appropriate for each stage.