As organisms, human beings interact with the world and each other through causal mechanisms that control us and every other physical thing. As persons, we act in the world through our thoughts, emotions, attitudes, or desires.
Accordingly, human beings are describable in two distinct, but complementary ways: in terms of the way the world is, through scientific descriptions of the causal mechanisms and laws that explain physical things, or, in terms of the way the world seems, through descriptions of personal experiences and meanings.
One or the other way of describing human beings comes into focus depending on the questions we ask about ourselves or the world. The features of personal experience—thought, feeling, speech and action—are amenable to standard scientific explanation as specific changes in the body. Traditionally, scientific research has had much to say about the physical nature of pain, but much less about the personal experience or meaning of pain. Indeed, the meaning of pain remains a blind spot in knowledge.
A description of a human being as a person means that there is a way of understanding of human beings in which personal experience and meaning, rather than physical causation alone, is needed to answer the question, “What is happening?”
Human persons can distinguish between how things are in the world and how things seem to me. I can recognise within myself a perspective or point of view on the world and identify it as belonging to me. Every person has such a unique perspective; this is partly what it means to be a person rather than a physical thing. In contrast, a scientific description of the world does not presuppose any personal point of view. Physical science does not use words like “I”, “here,” or “now”. Does this mean that “persons” are unobservable to standard quantitative science?
Possibly. Imagine a complete explanation of pain according to the final neurophysiology of pain—whatever it turns out to be. Such an explanation of pain would, to put it very crudely, accurately map specific neurophysiological changes in physical parts in the living human organism and all their true causal interactions across time. However invaluable such an explanation would be to pain medicine, it could not describe the way pain seems to the person who experiences it, for which of the physical objects described in this explanation is me with pain, here, now? Immediate pain always seems a certain way to persons, and this “seeming” determines the experience of the person with pain. In describing personal pain, human beings use language with other meanings than the language used in neurophysiology. The final neurophysiological explanation of pain therefore could explain only one dimension of pain in human beings—the physical dimension—in language that could not capture the personal experience, burden, or meaning of pain.
A philosophical assumption of neurophysiology is that a person is identical with his or her body. Person and body are one and the same thing. In terms of personal experience, however, the identity between person and body escapes personal understanding. For example, when I feel a pain, there is no information or evidence, or nothing that I could discover about my body subsequent to the experience of pain, that could demonstrate it to be false. When I feel a pain, I simply know that I am in pain.
In person to person interactions, we commonly respond to each other as though we are not identical with the human body, but in a compelling sense operating “through” the body, which seems to be a vehicle of thought, emotion, pain or suffering. We feel that each person we encounter in the world is a unique perspective that is not the body, but the “self”, which peers out through the face. The human face is the social instrument of persons. In seeking to understand you, or adjust how the world or your experience seems to you, I interact with you through your embodied perspective.
In pain experience, it is my loss of personal control over my body, and its dominion over me, that create the compelling sense, for me and for others, of an “incarnate” person. Pain imposes a significant vulnerability on persons: the vulnerability of a free person who is overwhelmed in his or her body by the presence of pain. This can make the person, and the person’s significant others, feel answerable for what he or she experiences.