Online research in philosophy

Newcomers to the philosophy of mind are sometimes resistant to the idea that pain is a mental state. If asked to defend their view, they might say something like this: pain is a physical state, it is a state of the body. A pain in one’s leg feels to be in the leg, not ‘in the mind’. After all, sometimes people distinguish pain which is ‘all in the mind’ from a genuine pain, sometimes because the second is ‘physical’ while the first is not. And we also occasionally distinguish mental pain (which is normally understood as some kind of emotional distress) from the ‘physical pain’ one feels in one’s body. So what can be meant by saying that pain is a mental state? Of course, it only takes a little reflection shows that this naive view is mistaken. Pain is a state of consciousness, or an event in consciousness, and whether or not all states of mind are conscious, it is indisputable that only minds, or states of mind, are conscious.2 But does the naive view tell us anything about the concept of pain, or the concept of mind? I think it does. In this paper, I shall give reasons for thinking that consciousness is a form of intentionality, the mind’s ‘direction upon its objects’. I shall claim that the consciousness involved in bodily sensations like pain is constituted by the mind’s direction upon the part or region of the body where the sensation feels to be. Given this, it is less surprising that the naive view of pain says what it does: the apparent ‘physicality’ of pain is a consequence of confusing the object of the intentional state—the part of the body in which the pain is felt—with the state of being in pain.

A functional interpretation of facial expressions of pain is welcome. Facial expressions of pain may be useful not only for communication, such as inviting help. They may also be of direct use, as parts of writhing pain behavior patterns, serving to get rid of pain stimuli and/or to suppress pain sensations by something akin to hyperstimulation analgesia.

Postulating the subcortical organization of human consciousness provides a critical link for the construal of pain in patients with impaired cortical function or cortical immaturity during early development. Practical implications of the centrencephalic proposal include the redefinition of pain, improved pain assessment in nonverbal humans, and benefits of adequate analgesia/anesthesia for these patients, which certainly justify the rigorous scientific efforts required. (Published Online May 1 2007).

There are a number of different matters that come under the heading of ‘consciousness’. One of them is phenomenality, the feeling of say a sensation of red or a pain, that is what it is like to have such a sensation or other experience. Another is reflection on phenomenality. Imagine two infants, both of which have pain, but only one of which has a thought about that pain. Both would have phenomenal states, but only the latter would have a state of reflexive consciousness. This entry will start with phenomenality, moving later to reflexivity and then to one other kind of consciousness.

Do animals other than humans feel pain? How do we know? Well, how do we know if anyone, human or nonhuman, feels pain? We know that we ourselves can feel pain. We know this from the direct experience of pain that we have when, for instance, somebody presses a lighted cigarette against the back of our hand. But how do we know that anyone else feels pain? We cannot directly experience anyone else's pain, whether that "anyone" is our best friend or a stray dog. Pain is a state of consciousness, a "mental event", and as such it can never be observed. Behavior like writhing, screaming, or drawing one's hand away from the lighted cigarette is not pain itself; nor are the recordings a neurologist might make of activity within the brain observations of pain itself. Pain is something that we feel, and we can only infer that others are feeling it from various external indications.

Our subjective sensory experiences are thought to be heavily shaped by interactions between expectations and incoming sensory information. However, the neural mechanisms supporting these interactions remain poorly understood. By using combined psychophysical and functional MRI techniques, brain activation related to the intensity of expected pain and experienced pain was characterized. As the magnitude of expected pain increased, activation increased in the thalamus, insula, prefrontal cortex, anterior cingulate cortex (ACC) and other brain regions. Pain-intensity-related brain activation was identified in a widely distributed set of brain regions but overlapped partially with expectation-related activation in regions, including the anterior insula and ACC. When expected pain was manipulated, expectations of decreased pain powerfully reduced both the subjective experience of pain and activation of pain-related brain regions, such as the primary somatosensory cortex, insular cortex, and ACC. These results confirm that a mental representation of an impending sensory event can significantly shape neural processes that underlie the formulation of the actual sensory experience and provide insight as to how positive expectations diminish the severity of chronic disease states.

This paper discusses recent neuroscientific research that indicates a solution for what we label the ''causal problem'' of pain qualia, the problem of how the brain generates pain qualia. In particular, the data suggest that pain qualia naturally supervene on activity in a specific brain region: the anterior cingulate cortex (ACC). The first section of this paper discusses several philosophical concerns regarding the nature of pain qualia. The second section overviews the current state of knowledge regarding the neuroanatomy and physiology of pain processing. The third section highlights the recent research by Rainville et al. [(1997) Pain affect encoded in human anterior cingulate but not somatosensory cortex, Science, 277, 968-971], which suggests that pain affect is encoded in the ACC. The final section of the paper spells out exactly how these data affect the causal problem of pain qualia.

How can a pain wake you up? You were not dreaming, nor did any bodily stimuli filter into your consciousness. You did not just wake up and realize you were in pain, as you might wake up and realize it is Saturday. You were deeply, dreamlessly asleep, and suddenly you were awake, and in pain. How is this possible? If pain exists only inasmuch as it is experienced, it seems that the pain did not exist when you were asleep, and so could not have woken you up. I shall argue that you were woken by a pain sensation that you did not know you had, so that the distinction between what is and what is known holds even for the contents of consciousness. This illuminates the relationship between consciousness and attention, and casts light on the Classical Empiricist tradition that identifies the foundations of knowledge with direct experience.