It is easy to view consciousness as a kind of magic. In religion it is represented by the mysterious soul, and in science the concept of consciousness at first appears quite alien. But many fields, such as the study of what distinguishes life from nonlife, had their earlier magical states eroded by careful scientific study. Consciousness is in the midst of a similar revolution.
The investigation of our own awareness is a blossoming scientific field, where experiments are illuminating exciting details about this most intimate of scientific subjects. In my book The Ravenous Brain, I describe the latest consciousness science and how we are closing in on establishing a consciousness meter—a way to measure levels of awareness in any being that may be able to experience the world. Consciousness is in many ways the most important question remaining for science.
But the nature of consciousness is not just a vital question for science; it’s also the source of some of society’s thorniest, most fundamental ethical dilemmas.
On a personal level, consciousness is where the meaning to life resides. All the moments that matter to us, from falling in love to seeing our child’s first smile, to that perfect holiday surrounded by snow-capped mountains, are obviously conscious events. If none of these events were conscious, if we weren’t conscious to experience them, we’d hardly consider ourselves alive—at least not in any way that matters.
Whether I’m reveling in a glowing pleasure or even if I’m enduring a sharp sadness, I always sense that behind everything there is the privilege and passion of experience. Our consciousness is the essence of who we perceive ourselves to be. It is the citadel for our senses, the melting pot of thoughts, the welcoming home for every emotion that pricks or placates us. For us, consciousness simply is the currency of life.
Although some philosophers and scientists suspect that consciousness is a pointless side effect of cognitive processes, I believe the opposite: that our consciousness might indeed be responsible for our greatest intellectual achievements in both the arts and sciences. Whether our creativity and insight originates in our unconscious mind or not (I believe that the role of the unconscious has been overestimated), at the very least, our consciousness is the conduit to inspect these gems of inspiration and the driving force for turning them into reality.
It is not surprising, therefore, that questions about consciousness lie at the heart of many of our most fundamental ethical debates, one of which is abortion and the right to life. This is an appropriate point for me to play my proud father card and slip in a couple of pictures of my daughter, Lalana. The ultrasound was taken halfway through pregnancy, at 20 weeks. Soon after this scan, we could clearly feel her kicking.
The second image is a recent photo of her. As a 2-year-old, Lalana runs around everywhere and has a vocabulary of a few hundred words. She can convey events to us that happened days or weeks before, usually because she is still so excited about them. She can also store wishes for the future. For instance, we might tell her offhand that when we get home, we’ll play with making bubbles. Hours later, as soon as she enters the house, she’ll run straight to the shelf with the bubble bottle and scream, “Bubbu! Bubbu!” She has a strong set of loves and hates, and her emotionally sensitive, passionate, cheeky, disturbingly stubborn personality is already pronounced.
Having prided myself on my objectivity throughout my adult life, I’ve embarrassingly found that my daughter is the main exception to this aim: I’ve not only been taken aback by how fiercely I love her but also by how proud I am of her and how quickly I distort the truth to make her seem exceptional in every way. But when I can step back from these views, I ask myself: At what point did she become conscious? Obviously she is conscious now, as she can tell me her inner thoughts via language. But when did she start experiencing her environment? On a personal, intuitive level, I had little doubt that her first intense bursts of laughter at my silly antics, when she was a few months old, reflected a substantive consciousness. But was she conscious well before this? Was she aware when she was still in the womb, kicking away? Or could she only experience things when she first opened her eyes to the outside world on the day of her birth?
Finding answers to these questions isn’t merely a matter of curiosity. In the United States, people have been murdered for carrying out abortions. In many other countries, abortion is illegal even if the woman has been raped, and some prominent U.S. politicians, including Republican vice-presidential nominee Paul Ryan, support similarly harsh laws. Although such positions are usually determined by religion, a related mindset is that fetuses are already conscious and even capable of feeling pain. Indeed, this has recently been the basis states have used to further restrict a woman’s rights on this issue, with Arizona the latest state to join this group by disallowing abortions after 20 weeks.
But what does science have to say on this matter? The evidence is clear that a fetus can respond to sights, sounds, and smells, and it can even react to these by producing facial expressions. The evidence is equally clear, however, that these responses are generated by the most primitive parts of the brain, which are unconnected to consciousness, and therefore these actions don’t in any way imply that the fetus is aware. Furthermore, the fetus is deliberately sedated by a series of chemicals produced by the placenta, so even if it had the capacity for consciousness, there is almost no chance that it could ever be conscious in the womb. Consequently, it can’t consciously feel pain.
But what if the fetus is removed from the womb and its sleep-inducing chemicals? Will the fetus suddenly be conscious in the outside world? In adult humans, for normal consciousness to occur, it is now generally agreed that two sets of regions need to be intact, functional, and able to communicate effectively with one another: the thalamus, a kind of relay station in the middle of the brain that connects many regions with many others; and the prefrontal parietal network, our most high-level, general purpose section of cortex. If either the thalamus or prefrontal parietal network is substantially damaged, the patient is likely to enter into a vegetative state, with virtually no sign of consciousness.
When do these brain regions form in the growing fetus? Only after about 29 weeks are the connections between these areas properly laid out, and it takes another month or so before the thalamus and the rest of the cortex are effectively communicating, as revealed by brain waves. So it’s highly unlikely that consciousness, at least in any form that we’d recognize as human awareness, arises before about 33 weeks into pregnancy. There are therefore no scientific reasons for restricting abortion on the grounds that the fetus will experience pain, at least until very late in pregnancy. This evidence has heavily influenced my views here, and consequently I am very much pro-choice.
Another ethical issue that hinges on questions of consciousness is that of animal rights. Every person on the planet, on average, consumes twice his or her weight in animal-derived food each year. Food production, as well as animal experimentation, could be causing the suffering of many millions of animals yearly.
If no animals except humans have consciousness, there’s no problem, as suffering requires consciousness. But if even those animals classically assumed to have very limited mental faculties, such as poultry and fish, have a substantive awareness and significant capacity for suffering, then are we justified in inflicting all this pain and discomfort on them?
If science could come up with some means of testing for the presence of consciousness in other animals and perhaps also a way of gauging the extent of consciousness when it’s found, this would have a huge impact on all ethical spheres of the animal rights debate.
On the surface, because animals can’t use language to tell us they are conscious, this seems an intractable problem. But a surprising amount of evidence has emerged that addresses the question of animal consciousness. For a start, we can ask which other species have brain regions similar to those we know are critical for human consciousness, namely the thalamus and prefrontal parietal network. Most mammals share these structures with us in some form, suggesting strongly that they too have some significant levels of consciousness. But this is a problematic approach, ignoring the possibility that very distant species independently evolved the capacity for consciousness. For instance, crows can use a series of tools to hook a juicy grub, and octopuses can open a screw-on lid to a jar to retrieve a tasty crab. Although these animals have no cortex, they appear to demonstrate a mental life that many would classify as conscious.
The most prominent scientific theories of consciousness are converging on the idea that it is related to a certain kind of information processing, in which multiple strands of data are drawn together, and that it is dependent on a certain kind of network architecture. Arguably the most popular theory along these lines, information integration theory by Giulio Tononi, effectively assumes that consciousness is a continuum across the animal kingdom. If so, even the lowly nematode worm, with a few hundred neurons, will have some, albeit minimal, level of consciousness. If something approximating this theory proves correct, it has huge implications for our relationship to all animals on the planet.
But even if we assume that there is a continuum of consciousness, this is of limited use in helping answer questions of animal rights. For instance, a worm may indeed have a capacity for some consciousness, but the way it experiences the world may be infinitesimally limited compared to human awareness. More pertinent for ethics is the scientific exploration of whether other animals have advanced forms of consciousness, such as self-awareness. This can be tested using the mirror test: A spot of paint is placed on an animal’s face, and it is then presented with a mirror. Many animals will simply attack or try to escape from the apparent foe in the mirror, but a select few will recognize themselves, as demonstrated by them trying to remove or at least examine the strange spot. The current list of animals that clearly pass this test includes chimpanzees, orangutans, gorillas, dolphins, elephants, pigs (on a modified version of the test), and even magpies. But this list of species is sure to grow as more animals are tested in ways that are most appropriate for them.
Another marker of an advanced consciousness is something called metacognition, the ability to be aware of your own mind and report on it, for instance by saying: “I’m sure I saw that cat in the woods,” or “You might have seen a cat, but I didn’t spot anything.” In human experiments, it is seen as definitive evidence of consciousness. But we are not the only species to have this skill.
Metacognition in other species is usually measured using a gambling task: An animal makes a decision about a stimulus and can then press either a high-risk button that promises a large food reward if the decision was correct but food restriction if it was wrong, or a low-risk button with a meager reward regardless of whether the animal is right or wrong. If the animal has significant metacognition—in other words, if it knows whether it is just guessing or if it has solid knowledge about a given stimulus—then it should usually press the high-risk button when it knows the correct answer and the low-risk one when it’s wrong. This is exactly what several other species, including the great apes and monkeys, do. These species demonstrate an advanced form of consciousness that in humans is definitive evidence of our awareness.
My take on all this data is that it is extremely likely that all the species that can recognize themselves in the mirror or show metacognitive abilities have an advanced form of consciousness. But for any species that hasn’t yet passed these tests, we simply don’t know whether they lack the ability or just haven’t been tested appropriately. The cautious attitude, I believe, is to assume that all mammals and the octopus at the very least, but possibly many more species, have a significant capacity for consciousness.
Consequently, I am a vegetarian, as are several prominent consciousness researchers. I believe it would be ethically consistent for us to extend our own rights to life and freedom from torture to any species that can recognize itself in the mirror, show clear metacognition, or even demonstrate extensive tool use. Barring all these animals from the food industry and passing laws to protect them based on their consciousness would be a radical step and not one that I can see any political leader advocating anytime soon. Nevertheless, it would be a consistent and caring departure from the way much of society currently views animals, and it would acknowledge the advances in our scientific understanding of the mental lives of these other species.
Consciousness research informs other political issues as well. For instance, how can we assess the level of consciousness remaining in someone who has suffered severe brain damage and is in a vegetative state? At what point should we let such patients die? And it is possible that in the decades to come, we might also need to start thinking about how we assess artificial forms of consciousness and what rights we consequently need to bestow on such beings.
Therefore, not just for its own sake but for evaluating many ethical dilemmas, consciousness science is a vital field. Anyone interested in key political debates may want to keep a close eye on its progress in the years to come.