Octopus Consciousness and the Ethics of Animal Captivity
Callie Williamson
PHI 1110: Introduction to Philosophy
April 22, 2022
When it comes to the study of the octopus, it is more often a subject of biology rather than philosophy. However, the versatile creature can not only be studied for its anatomy and function within an ecosystem, but also for its perceived intelligence and, perhaps, its consciousness. If octopi possess consciousness at a comparable level to some mammals, like dogs or humans, ethical questions arise about captivity, habitat destruction, and farming for consumption. In fact, if an octopus has a rich interior life, even if it is entirely unlike a human’s life, then humans should perhaps be treating them not as pets, or food, or display animals, but nearly as equals.
The definition of consciousness is hotly debated, and “consciousness” is a word with a multitude of meanings, such as being awake vs asleep or being self-aware (Halina 2017). To discuss the experience of what it means to be an octopus, consciousness will be defined as the ability to have a subjective experience of life. To have a subjective experience is to live a life that is “good” or “bad” and judge experiences on subjective quality, as opposed to purely assessing life in terms of pain vs. pleasure, or living life in mechanical darkness without any sort of awareness. This can also be referred to as phenomenological consciousness or sentience. Assuming phenomenological consciousness means to assume that, while we may never know exactly what it is like to be an octopus, we are assuming that it is like something; that the octopus is having an experience (Nagel 1974).
The dominant assumption in the study of both animal and human consciousness is neuralization – that consciousness is stored in the nervous system (Carls-Diamante 2017). In other words, the nervous system processes sensory information into a subjective experience. For humans and other vertebrates that are assumed to have consciousness, the brain is the part of the nervous system that houses said consciousness (Low 2012). The brain and spinal cord, which make up the central nervous system in vertebrates, contain the “neurological substrate” necessary for consciousness and performing behaviors based on subjective experience (Low 2012). Octopi are an exception. Octopi have decentralized nervous systems, meaning that the bulk of their processing power is distributed throughout the peripheral nervous system, as opposed to all being stored in the central hub of the brain (Carls-Diamante 2017). The nervous system is so decentralized that it is not unreasonable to question the octopus brain’s ability to process sensory information, much less assess it into a subjective experience.
Assuming neuralization, we must investigate the anatomy and structure of the octopus nervous system to attempt to conceptualize its consciousness. Each of the eight arms contains a robust and mostly independent section of the peripheral nervous system (Carls-Diamante 2017). These sections both receive and process sensory input and create their own movements (Sumbre et al. 2001). This means that octopus arms sense their environments through touch and motion, process that information on their own, and move independently of brain decisions. The brain is not involved, or at least very indirectly involved, in the movement of octopus arms, and research indicates that the brain may not have a mental map of the body (Carls-Diamante 2017). Biologists are fairly certain that the octopus brain does not have access to, nor does it process, any proprioceptive information (information about where the body is in relation to the environment), so it has been questioned whether or not octopus consciousness has a “proprioceptive component” (Carls-Diamante 2017).
For me, this introduces a further, possibly contradictory question. Perhaps the consciousness stored inside the octopus brain does not have a proprioceptive component, but the arms certainly process proprioceptive information. Can an octopus contain multiple consciousnesses, and if so, do they look different from one another? In other words, is it possible for an octopus to have some consciousnesses that have proprioceptive components, and others that do not? The implication of an octopus brain being unaware of its body is that if its main consciousness is stored in the brain, then an individual octopus is possibly unaware that it is a physical being. While some bio-philosophers are concerned with whether animals are a mechanical body filled with darkness, is it possible for an octopus to think it is an awareness in a vacuum, without a body or an environment?
In order for an octopus to have multiple consciousnesses, and to have multiple outside the brain, then the peripheral nervous system contained inside the arms would have to be able to support consciousness. Most research to this end points to a 1963 study that found that after amputation, octopus arms can function and respond the way that intact ones can (Rowell 1963). Amputated octopus arms can perform motor functions and process and react to sensory information just as well as intact ones, indicating that, on some level, octopus arms have independent localized phenomenological consciousness states (Carls-Diamante 2017). This is supported by further investigation into the structure of the octopus nervous system, which shows that the nerve connections between the arms and the brain are simple and limited (Carls-Diamante 2017). Octopi are well-known to perform precise motor tasks, like bringing food to their mouths and opening jars. If the brain has no say over motor control and no processing power for sensory information, the next logical assumption is that the arms must be able to decide for themselves what and how to move through space.
This is not to say that an octopus has a fully developed, mammalian sense of self within each arm. The arms are still part of the peripheral nervous system, and nothing about their neurological substrate indicates that they can support higher processing (Carls-Diamante 2017). Then again, the structure of the nervous system appears as though the octopus brain does not support a mammalian consciousness on its own either. But why should we expect octopus consciousness to look anything like vertebrate, mammalian, or human consciousness? Assuming neuralization, a decentralized nervous system indicates that octopus consciousness cannot possibly be unified, the way that vertebrate consciousness is assumed to be (Carls-Diamante 2017; Bayne 2010). Cephalopod consciousness, if it is indeed disunified, developed entirely separately from humans, and it is necessary to look at it separately in order to attempt to understand and support octopus welfare.
In the evolutionary scheme of things, humans are not particularly distant relatives from any other mammals. Humans and mammals of comparable cognitive power, like chimpanzees, diverged in their evolution 5-7 million years ago, while humans and cephalopods diverged closer to 600 million years ago; our last common ancestor was a flatworm, which is essentially as close to cognitive ground zero as you can get without being single-celled (Halina 2017). That means that cephalopods, and octopi in particular, have been able to develop consciousness completely separately from vertebrates, essentially giving us a look at what non-terrestrial, or maybe even non-biological, consciousness could be like. Thinking about what octopus consciousness might be like can help us to consider what alien life could be like, or if AI consciousness is possible (Halina 2017). The octopus, presumably, does not care about either of these implications though. For the octopus, our attention to its consciousness has the potential to increase its general welfare in captivity and in the wild, and raises some important ethical questions about how we treat other life forms that we do not and can not understand.
In conversations about consciousness, it is near impossible to say that we know something, but in cases of biology, we can know certain things and that certain behaviors have been observed. Octopi have two primary motivations, both of which have their origins in the mind. These motivations are the desire to explore and fear (Mather 2019). Octopi explore for interest and fun, not just for the extrinsic motivation of food. Octopi have been observed to thrive in “complex enriched environments,” and show signs of frustration and boredom when they have nothing to explore (Browning 2019). With regard to fear, octopi are in the phylum Mollusca, meaning they should be like clams and other shellfish, but they have no hard shell. Because of this, they often show signs of fear and the feeling of vulnerability when they do not have adequate shelter nearby (Browning 2019). To say that an octopus has any sort of intrinsic motivation, or even that it feels fear, is to assume some sort of recognizable consciousness. Biologists use these observations to make decisions about octopus welfare and care in captivity, and use octopus consciousness to make arguments about the ethics of octopus farming. However, I think that a larger question to be asked here is whether or not we should be keeping octopi in any captivity at all, including farming, if they have the potential for a type of consciousness that we can never hope to grasp.
Be it ethical or not, humans have decided that mammals and other vertebrates with comparable neural structures can be kept in captivity by humans. Mammals that we see as more intelligent and closer to human consciousness, like dogs, often get more freedom and better societal treatment, but not always. Invertebrates are not considered to be conscious by the average person, and are certainly not treated with equal consideration for their needs and welfare. If equal consideration is, in fact, the most ethical way to treat non-human animals, then it seems logical to assume that we should attempt to discover and meet the needs of octopi (Singer 1989). Full disclosure: I am not a biologist. However, I do not think that captivity is a good place to start attempting to meet the needs of octopi. The neurological structure of the octopus implies the support of a consciousness so different from humans and other vertebrates that one could call it alien (Halina 2017). If we approach octopus welfare in the same way that we approach vertebrate welfare, how can we assume that we are actually meeting an octopus’s needs? We cannot understand how they perceive and experience the world, nor can we really understand their behavioral responses to it. Their consciousness, should it exist, effectively lives on a different planet, in an entirely foreign neurological substrate. It seems to me that in keeping octopi in captivity, we run the risk of imprisoning equally intelligent lifeforms for our own viewing or consumption.
Granted, this same argument could be made for vertebrates citing the Problem of Other Minds, in which we do not and cannot ever know what any other human consciousness is like, never mind an animal’s (Avramides 2019). If we really cannot make assumptions about any organism’s consciousness, then we perhaps should not be keeping anything in captivity at all. Alternatively, maybe it is entirely ethical to keep animals captive, since they might all be empty and mechanical. This line of logic, while possible, does nothing to benefit octopus welfare, or really any animal’s welfare, since the issue of animal captivity is likely not going to disappear. However, the main merit of applying the Problem of Other Minds to this question is this: if we cannot ever hope to know what octopus consciousness is like, especially because it is almost certain to be entirely different from our own, then it is likely in everyone’s best interest if we take our hands off. Zoologists could replicate an octopus’s natural habitat exactly in captivity, down to the chemical content of the water, and we would still run the risk of damaging its welfare if an octopus has high-level consciousness and knows exactly what has been taken from it.
Theoretically, it is possible for a single octopus to contain several separate, mostly independent consciousnesses. What those consciousnesses look like is probably beyond the scope of human imagination – they are conscious exotica on Earth (Halina 2017). Perhaps attempting to understand octopus consciousness could make humans better keepers for them and help us meet their needs in captivity, but when working with a lifeform we cannot understand, then it is in everyone’s moral interest to leave the octopi alone.
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