Yitong Zhou

The geometric trinity of gravity provides a prominent case of underdetermination: all theories reproduce the metric dynamics of General Relativity (GR) while attributing gravitation to different affine structures. I develop a metric-affine equivalent of GR, and argue that it constitutes an overarching theory of the trinity. With this framework, the standard formulations of the trinity surjectively realize distinguished affine sectors of a common configuration space, their actions arise by restriction of a common variational principle, and their solution spaces map exactly onto the corresponding sectors. I then argue that this framework provides a formal basis for a conventionalist interpretation of affine structure: the connection is retained representationally while remaining unconstrained by the dynamics. This account clarifies both the scope and the basis of geometric conventionalism, and extends the underdetermination problem beyond the three standard members of the trinity.

The Lewis-Skyrms signaling game provides an effective explanation of how signals, as primitive linguistic elements, can emerge. In the standard signaling game model, both sender and receiver recognize a shared set of signals and gradually establish associations between signals, states, and behaviors through repeated interactions. Herrmann and VanDrunen (2025) challenge the assumption that the receiver can always correctly identify signals and propose the “attention game” to model how receivers learn to allocate attention properly in order to identify signals. Building on this framework, this paper further explores signaling games based on biological attention mechanisms. It examines how asymmetries—stemming from uneven attention allocation and differences in the transmission success rate of signal features—impact signaling outcomes. This study aims to show how attention mechanisms facilitate signal selection and how such selection processes improve the efficiency and robustness of communication.

General relativity (GR) describes gravity through the curvature of spacetime. However, there are two equivalents of GR that describe flat spacetimes with gravitational effects attributed to torison or non-metricity. These theories, together with GR, are known as the geometrical trinity of gravity and are said to present a case of underdetermination by Wolf et al. (2024). In this article, I argue against this stance by examining the empirical equivalence and possible interpretations of the trinity. I propose a new framework where the trinity emerge as different gauge-fixed versions of a unifying theory. Thus I contend that the apparent disagreements on spacetime ontology arise from different gauge choices without physical significance, thereby breaking down the underdetermination.