The Terri Schiavo case has raised a wide discussion about the nature of consciousness and what consciousness might be attributed to her. As a general reader, I would like to offer my understanding of current scientific knowledge about consciousness. I invite comments and corrections.
What is consciousness? To start, we define consciousness simply as awareness. We do not further define awareness with words, but point to the common experience of awareness so that we know what we are talking about. There are three, qualitatively different kinds of consciousness. All kinds of consciousness are products of neurological systems. Organisms without nervous systems, such as trees, do not have consciousness of any kind. The differences between the kinds of consciousness are related to differences in complexity of the nervous systems of organisms (more about this relationship between awareness and neurology below).
The three kinds of consciousness are sentience, located consciousness, and empathy. Sentience is the most elementary form of awareness. It is simple feelings, such as pressure, pain, and heat. Sentience accompanies neurological activity, so it exists in all organisms with nerves. A decapitated frog, for instance, whose nervous reflexes still worked, would be sentient in its leg when stimulation of a foot reflexively causes the leg to withdraw aware from the source of stimulation.
Located consciousness (my term) is positional awareness of environment. The organism is aware of its surroundings. It is aware of objects in its perceptual space. Positional awareness requires a centralized nervous system with some brain functions. It does not require the full panoply of brain capabilities of a human. Locational consciousness exists in different degrees of complexity in different organisms, depending upon brain complexity. We can distinguish degrees of brain complexity among animals. Given sufficient brain complexity, positional awareness can include self-consciousness.
Empathy is awareness of the awareness of other animals. Empathy is not uniquely human, but other animals, e.g., higher primates, do not have brain complexity sufficient to experience empathy to the degree that we do. Brain physiologists and psychologists have identified specific, distinct regions of cells that produce self-consciousness and empathy. Still other cellular regions are responsible for simple positional awareness.
Because there is a general scale of increasing complexity among vertebrates, we may say there is a scale of increasingly complexity of awarenesses. Starting at the "bottom" and most simple and going to the "top" and most complex, these consciousnesses are: sentience, located consciousness, self-consciousness (which I classify as a kind of located consciousness), empathy.
I stated that the three kinds of consciousness are qualitatively different. By qualitative difference, I mean that, based on having one kind of consciousness alone, we would not be able to imagine what it would be like to experience another kind of consciousness. If an organism has only sentience, it cannot imagine what it would be like to have positional consciousness. (Without higher brain functions, it would not have the brain capability for imagination, so this a speculative example.) If an organism has self-consciousness, but not capacity for empathy, it would not know that other organisms have self-consciousness and it would not be able to put itself in their place when they suffer (which is what empathy enables us to do). Qualitative difference means that there are significant differences between the kinds of awareness.
It is the possession of self-consciousness and our experience of our own self-consciousness that raises confusion in understanding Terri Schiavo's condition. Here is how I understand the issues involved. I readily admit my explanations are suggestive and speculative. I am going to make some analogies, in explaining the issues, but these are only for clarity and do not denigrate Terri Schiavo's humanity.
Some organisms have located consciousness, but lack self-consciousness, for instance, fish. A fish has orientation in its watery environment, but the fish lacks awareness of itself as a "self". It doesn't name itself, for instance. When another fish attacks it and inflicts pain or eats part of it, the fish under attack feels pain; but, because it does not have a sense of self, it does not know that it, "this fish, Ralph," is hurting. This example can be extended to us humans. Pain can exist without being your pain; as a result, you do not suffer. In the Nazi concentration camps, when prisoners were tortured, some prisoners could separate their self-consciousness from their positional consciousness and from their sentience. They endured torture because their selves did not experience the pain. For instance, they imagined that they were standing aside from their bodies (they disowned their bodies, so to speak) and were watching the torture of "someone else". There was pain, but their selves did not feel it.
We have been analyzing consciousness by working up a scale of complexity and adding kinds of awareness. We can work backwards, too. We can substract degrees of complexity and organization, thereby substracting kinds of consciousness, because the neurological basis is not present. This is pertinent to analyzing Terri Schiavo's condition.
In the case of Terri Schiavo, Mrs. Schiavo is sentient. Most doctors say she does not have located consciousness (she is unaware of her environment). Without located consciousness, she is unable to have directed attention. Without directed attention, she cannot have self-consciousness. When she is described as in a persistent vegetative state, I believe this is what is meant. Some doctors say she does have located consciousness. If she has located consciousness, she has consciousness, but - this is the point - she does not necessarily have self-consciousness. Finally, without self-consciousness, she does not have empathy.
Without self-consciousness, Terry Schiavo does not have a self. This statement sounds terrible and flies in the face of religious belief that the self is anchored in distinct, unitary, nonmaterial entity. But neurologically, the self is a neurological function enriched by experience gained within positional awareness. Pain, as a form of awareness, could exist in her neurological system, but she would not know it and, therefore, she would not suffer from it. You, yourself, cannot suffer, if you do not have a self to experience pain and do the suffering. For this reason, the medical opinion that her dying due to lack of food and water would not involve suffering has a high credibility. Withdrawal of her feeding tube would not be cruel, because it does not inflict suffering. Mrs. Schiavo's brother-in-law, who has visited Terri Schiavo in her room since her feeding tube was removed, stated on CNN that Terri Schiavo is peaceful. There is much medical and scientific evidence to confirm that his personal observation is true.
(Revised.)
Recent Comments