The “Slicing Problem” is a thought experiment that raises questions for substrate-neutral computational theories of consciousness, including those that specify a certain causal structure for the computation like Integrated Information Theory. The thought experiment uses water-based logic gates to construct a computer in a way that permits cleanly slicing each gate and connection in half, creating two identical computers each instantiating the same computation. The slicing can be reversed and repeated via an on/off switch, without changing the amount of matter in the system. The question is what do different computational theories of consciousness believe is happening to the number and nature of individual conscious units as this switch is toggled. Under a token interpretation, there are now two discrete conscious entities; under a type interpretation, there may remain only one. Both interpretations lead to different implications depending on the adopted theoretical stance. Any route taken either allows mechanisms for “consciousness-multiplying exploits” or requires ambiguous boundaries between conscious entities, raising philosophical and ethical questions for theorists to consider. We discuss resolutions under different theories of consciousness for those unwilling to accept consciousness-multiplying exploits. In particular, we specify three features that may help promising physicalist theories to navigate such thought experiments.

The boundary problem is related to the binding problem, part of a family of puzzles and phenomenal experiences that theories of consciousness (ToC) must either explain or eliminate. By comparison with the phenomenal binding problem, the boundary problem has received very little scholarly attention since first framed in detail by Rosengard in 1998, despite discussion by Chalmers in his widely cited 2016 work on the combination problem. However, any ToC that addresses the binding problem must also address the boundary problem. The binding problem asks how a unified first person perspective (1PP) can bind experiences across multiple physically distinct activities, whether billions of individual neurons firing or some other underlying phenomenon. To a first approximation, the boundary problem asks why we experience hard boundaries around those unified 1PPs and why the boundaries operate at their apparent spatiotemporal scale. We review recent discussion of the boundary problem, identifying several promising avenues but none that yet address all aspects of the problem. We set out five specific boundary problems to aid precision in future efforts. We also examine electromagnetic (EM) field theories in detail, given their previous success with the binding problem, and introduce a feature with the necessary characteristics to address the boundary problem at a conceptual level. Topological segmentation can, in principle, create exactly the hard boundaries desired, enclosing holistic, frame-invariant units capable of effecting downward causality. The conclusion outlines a programme for testing this concept, describing how it might also differentiate between competing EM ToCs.

This paper proposes the "Heavy-Tailed Valence” (HTV) hypothesis: the notion that human capacity for emotional experiences of pleasure and pain spans an incredibly wide range of intensity, a minimum of two orders of magnitude between the most mild and the most intense experiences. We set out a thought experiment, the "integer experiment test", to demonstrate that such a capacity is not arbitrary: a wide range could not simply be mapped onto a narrow range without losing something tangible. In directional support of the hypothesis, we discuss three stylized facts, based on heavy-tailed neurological functions, the application of pain/discomfort scales, and the existence of extreme events. We also present five intuitions against the hypothesis and suggest reasons to reject these counter-intuitions. Recognizing this theoretical ambiguity, we turn to specifying additional assumptions under which the hypothesis results in testable empirical claims. A pilot survey (n=97) investigated how people describe their most intense experiences, finding tentative support for the hypothesis in preparation for a larger survey revised based on insights from the pilot. Over half said their most intense painful experience was at least three times more intense than the second most intense. Simulations further suggest an underlying heavy-tailed distribution of experience valences is more consistent with the survey responses. The results also raise doubts over the cardinal interpretation at the high end of 0-10 scales for pleasure or pain, with over 80% of respondents appearing to compress experienced intensity in order to report high values. Finally, we discuss how a larger future survey could mitigate the limitations in the pilot study and discuss potential implications of the hypothesis for wellbeing economics, ethics, and personal life choices.