The accident left David with a very unusual form of brain damage. If you scratched, pricked or kicked him, he felt no pain. But if he saw a lot of yellow, tasted oak, heard an opera singer hit a high C, made an unintentional pun, or had one of several other apparently random experiences, then he would feel pain, sometimes quite acutely.
Not only that, but he did not find the sensation of this pain at all unpleasant. He didn’t deliberately seek out pain, but he did not make any efforts to avoid it either. This meant that he did not manifest his pain in the usual ways, such as crying out or writhing. The only physical signs of David being in pain were all forms of involuntary spasm: his shoulders would shrug, eyebrows lower and rise in quick succession, or his elbows flap out, making him look like a chicken.
David’s neurologist, however, was deeply sceptical. He could see that David no longer felt pain as he had before, but whatever David was now feeling when he saw ‘too much yellow’, it couldn’t be pain. Pain was by definition an unpleasant thing that people tried to avoid. Perhaps his brain damage had made him forget what the sensation of real pain felt like.
Source: ‘Mad Pain and Martian Pain’ by David Lewis, in Readings in Philosophy of Psychology, vol. 1, edited by Ned Block (Harvard University Press, 1980)
Philosophers of mind are keen on pain. They are fascinated by the nature of subjective experience and its relation to objective knowledge, and nothing seems to be more subjective and at the same time as real as pain. Just ask anyone who has suffered extreme toothache. At the same time, we are usually pretty good at spotting if someone is in pain. Unlike other mental events, such as thinking about penguins, pain affects our outer demeanour as well as our inner experience.
So if you want to understand what it means to have a subjective experience, pain makes for a good case study. The story of David’s ‘mad pain’ is an attempt to play with the variables associated with pain to see which are essential and which are incidental. The three main variables are private, subjective experiences; typical causes; and behavioural responses. Mad pain has only subjective experience in common with ordinary pain; its causes and effects are quite different. If it is nonetheless accurate to describe mad pain as pain, then we should conclude that it is the subjective feeling of being in pain which is the essence of pain. Its causes and effects are merely incidental, and could be different from what they usually are.
Common sense is not univocal on this. On the one hand, it seems obvious to say that pain is essentially a subjective feeling. Only philosophers and psychologists would seriously suggest that it might be better defined in terms of stimulus-response or brain function. But on the other hand, common sense would also say that a subjective experience of pain which someone didn’t mind having and which caused no agitation would not be pain at all. That means the story of David is incoherent: despite what he says, he just couldn’t be feeling pain at all. His neurologist is right to be sceptical. And after all, we only have David’s word to go on. Why should we trust his ability to recognise his inner sensations as being the same as those he had when he hurt himself before the accident?
The nub of the issue, however, concerns the relation between the inner and the outer. It might seem easy to say that pain is defined by how it feels to the sufferer, and that this has an essential link to behaviours such as avoidance and grimacing. But this solution is too quick. For if pain really is a feeling, then why should it be inconceivable to experience pain without any of the associated behaviour? It’s no good just saying it must manifest itself in some way; you need to say why it must do so. Until you can, mad pain remains a possibility.
See also
| 23. | The beetle in the box |
| 26. | Pain’s remains |
| 32. | Free Simone |
| 39. | The Chinese room |