Some Foundational Problems in the Scientific Study of Pain

This paper is an attempt to spell out what makes the scientific study of pain so distinctive from a philosophical perspective. Using the IASP definition of 'pain' (1986) as our guide, we raise a number of questions about the philosophical assumptions underlying the scientific study of pain. We argue that unlike the study of ordinary perception, the study of pain focuses from the very start on the experience itself and its qualities, without making deep assumptions about whether pain experiences are perceptual. This in turn puts scientific explanation in a curious position due to pain's inherently subjective epistemic nature. The reason for this focus on the experience itself and its qualities, we argue, has to do with pain's complex phenomenology involving an affective/motivational dimension. We argue for the scientific legitimacy of first-person phenomenological studies and attempts to correlate phenomenology with neural events. We argue that this methodological procedure is inevitable and has no anti-physicalist ontological implications when properly understood. We end the paper by commenting on a discussion between two prominent pain scientists in the field, Don Price and Howard Fields, about the need to distinguish more dimensions in the phenomenology of pain and how to classify them vis-à-vis the recent scientific findings. Our interest in this discussion is not only to introduce some clarifications but also to show how "neurophenomenology" has already been shaping the scientific research and to back our claim about why this methodology is inevitable with an example. The scientific study of pain, one of the most controversial areas in neuroscience, is rife with philosophical problems. The complex physiological nature of pain, when combined with the multi-dimensional phenomenology of pain experience as revealed in clinical studies, presents not only empirical questions but conceptual puzzles as well. Among the foundational questions raised by scientific pain research, the following are especially relevant from a philosophical point of view: the subjective epistemic nature of the explanandum and the epistemological status of scientific explanations in the study of pain; the ontological nature of pain experience and its relation to underlying physiological processes; the composite nature of the experienced phenomenology of pain (especially its affective dimension); and finally, the striking contrast between pain and other modalities of perception like vision, hearing, and touch. But perhaps the most pressing question of all concerns a fundamental tension between pain as subjectively understood versus pain as objectively characterized, which constitutes the focus of our discussion below.