The Nature of Consciousness: Consciousness, Life and Meaning

Are Colors More Real Than Pain?

We perceive the world in at least two different ways: one is the sensations that come from the senses (seeing, smelling, touching, hearing, tasting) and one is the feelings that somehow are generated in response to things that are happening to our body (pain, pleasure, hunger, hate, fear, etc).

Colors and shapes seem to be direct perceptions of the world out there, whereas pain seems to be the fictitious outcome of a process in our brain.

It turns out that colors and shapes and sounds and so forth are not shared by all living organisms. As a matter of fact, every species has its own "sensations" that are different from other species. Some animals see the world in three dimensions, but some see it in two dimensions. Some see colors, and some do not. Other species may see "things" that we don't see. Their eyes are different and their brains are different. There is no evidence that what we "see" is what is out there (rather than, say, what the frog sees).

Colors and shapes and sounds and so forth are devices to "map" the outside world so that our body can deal with it in an efficient way. Once we build such a "map" of the outside world, we can, for example, move without hitting solid things and grab things that we want to eat.

Emotions are more of the same, but at a more primitive level. They direct our behavior, but they don't require a representation of the outside world. They just tell us "don't do that" or "do that".

While the ability to see and hear and smell seem to be more primitive than the emotions of pain and pleasure, it is likely to be the opposite.

What is more important for survival? To be able to map the world into objects of such a shape and such a color, or to be able to find food and detect danger in a millisecond?

The early multicellular organisms were probably incapable of any significant mapping of the world around them. They were capable, though, of avoiding dangerous places and moving towards more promising places. They were equipped with simple cells (the progenitors of today's nervous system) that could react to the temperature and to the chemical composition of the surroundings and simply move away or move towards them.

If floating in a pond, those cells would have been able to realize that the temperature was reaching a dangerous level (say, because of a nearby lava flow) and therefore cause movement in the opposite direction. This progenitor of "pain" was much more relevant than assigning a shape or a color to the pond and the lava flow.

The ability to map the world through the senses was a later development, one that provided organisms with an even more sophisticated survival strategy.

Ethical Issues in the Age of the Brain

For centuries the signs of life have been the heartbeat and breathing. It was impossible to measure the mental life of a person, easy to measure heartbeat and breathing.

A person was considered legally dead if the heart stops beating. That is a body-based definition.

Since the 1970s scientists have been able to measure brain activity, not just heartbeat and breathing. In 1963 David Kuhl experimented with emission reconstruction tomography (later renamed Single-Photon Emission Computed Tomography or SPECT). In 1972 Godfrey Hounsfield and Allan Cormack invented X-Ray Computed Tomography Scanning or CAT-scanning; and at the same time Raymond Damadian built the world's first Magnetic Resonance Imaging (MRI) machine. The following year Edward Hoffman and Michael Phelps created the first PET (Positron Emission Tomography) scanner, that allow scientists to map brain function. In 1990 Seiji Ogawa used "functional MRI" to measure brain activity based on blood flow.

Now that it is possible to measure brain activity, in the age in which we assign a higher status to the brain than to other organs, a new brain-based definition of "alive" might be required. The term “brain dead” has come into common use to imply that someone’s body is still alive but actually the “person” inside that body is dead.

That leads to new ethical issues. For example, a 12-week fetus has a higher degree of brain activity than an injured person in a persistent and irreversible vegetative stage, but the law grants the latter the full rights of a human being whereas it grants pretty much no rights to the former. Whether either one can be said to be a “thinking”, sentient being is debatable, but it is certainly inconsistent that we treat as a human being only the one with lower brain activity. Intensive-care units can keep people's bodies alive but do nothing to resurrect “dead” brains (brains whose thought-related activity is non-existent). The fetus, on the other hand, is living in a sort of "intensive care unit" (the mother's womb) but has a functioning brain. Whether that “functioning” can be said to be “thought” or not is a much bigger issue, but it is at least “more” than what the vegetative person has. Roughly the development of brain activity is: the sub-cortical brain appears at five weeks, the cerebral hemispheres differentiate at seven weeks, EEG activity is present at eight weeks, and the cortex forms at about 20 weeks gestation.

The issue was first advanced by the US pediatrician John Goldenring ("The brain-life theory: towards a consistent biological definition of humanness", 1985). Goldering was basing his opinion piece on flawed data, but he posed the correct question nonetheless: if the cessation of brain activity defines death, shouldn't the onset of brain activity define the beginning of life?

Human cognitive life may be viewed as a continuum from the onset of brain life (about eight weeks gestation) until brain death. In between the brain is definitely active. Before and after that continuum we don’t have any evidence that the brain is active other than for mechanical functions. John Goldering's rule of thumb was: "Whenever a functioning human brain is present, a human being is alive"; and viceversa.

According to Michael Gazzaniga (in the "The Ethical Brain", 2005), the human fetus at 13 weeks gestation has brain activity comparable to that of a sea slug; but the brain activity of a vegetative patient is even lower than that. And the near-term fetus has a brain that may well have cognitive capacity since it is more complex than the brain of a sea slug and the sea slug does have a primitive cognitive life.

Furthermore, within that continuum one may encounter cases in which brain activity has fallen below what we consider “human” or never reached that level. If a person's mental life declines to the point that his brain activity is similar to the brain activity of a dog or a rat, should that person still have the full "human rights" or only the rights granted to dog and rats?

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