Last updated: Sun, Aug 4, 2024
In his impressive 2002 book (The Blank Slate: The Modern Denial of Human Nature), neuroscientist Steven Pinker discussed the question of human nature. The great masses of research into cognition, of which pain research is just a small part, are showing in considerable detail that the way we think and feel and perceive the world is directly related to the way our nervous systems are wired.
Your sense of how things feel, for example, begins with the distribution of four types of touch receptors in your skin. Some receptors respond to changes in pressure and therefore detect movement or, when your fingers move across an object, detect the features of whatever you are touching. Other receptors respond to steady pressure and therefore detect the continuing presence of objects. Some receptors are close to the surface and respond to small, localized pressure, while others are deep and respond to pressure over a larger area. The size of features that you are able to detect through touch is determined by the sensitivity and distribution of receptors in your skin. As you age, you lose receptors and your tactile discrimination becomes less.
A short chain of neurons carries the touch sensations up the spine, through the thalamus, and into the sensory cortex where the sensations are put into spatial context. The signals continue into motor planning areas and other areas where the tactile signals are combined with other sensory input. So we make sense of our world.
With small or large variations, we are all put together this way, and so we feel the world in similar ways. Neuroscientists are painstakingly unraveling the nervous system and discovering in overwhelming detail the physical correlates of our feelings and thoughts. That's what neuroscientists do.
From the point of view of the neuroscientist, it seems natural to think of "human nature." Human nature is the result of the design features that we all share. Of course there are variations in genes, in development, in education, in pathology, but the common design leads to a common human nature. Why, then, should moderns deny that there is a human nature?
Pinker's thesis is that historical traditions have combined with modern social, political, and moral aspirations to produce an alternative view of us, the view that a person is born a "blank slate." In this alternative view, we are much more flexible, more moldable, more subject to influence by our experiences and learning. The two views have important implications related to education, opportunity, and personal responsibility, and hence these issues intersect with politics and religion.
Part of our common human nature is what is called a "theory of mind." This is a theory about what motivates the behavior of other humans. We see their behavior as motivated by their desire to achieve goals and guided by their beliefs. We see ourselves in the same way. While ordinary physical events have causes, human behavior has reasons. This view of human behavior may seem self-evident to you. If so, that is perhaps testament to how deeply this view is embedded within us. Scientists must work very hard to override the insights that this intuitive view of the world presents them with.
Certainly a theory of (others') minds would be useful to social beings such as ourselves, whose social functioning is so critical in individual and group success. Equipped with our theory of mind, we are prepared to infer motivations behind visible actions, which helps us to interact successfully. (In fact, neuroscientists have recently discovered that we are equipped with special structures called "mirror neurons" that allow/force us to infer what is happening internally to others based on what we can observe externally. The system of mirror neurons has some implications for the suffering of those in pain that I explore in The Challenge of Living in Pain.)
Is our standard-issue theory of mind sufficiently sophisticated to deal with biologically unusual situations? How might it interpret chronic illness? Might it not suggest that such behavior also is motivated by goals?