Foundations of Animal Sentience

Evan Thompson (University of British Columbia)
In 1892 Ernst Haeckel coined the term “biopsychism” to refer to the position that feeling is “a vital activity of all organisms.” He distinguished biopsychism from panpsychism, the position that “all matter is ensouled,” and from zoopsychism, the position that “real soullife,” by which he meant the separation of feeling and will, is the attribute only of higher animals and reaches its fullest development in the human being. In contemporary terms, biopsychism can be described as the thesis that all and only living systems are sentient. Clearly, this thesis depends on what “living” means.
One prominent family of theories addresses this question by trying to specify the organization that is necessary and minimally sufficient for a system to be living. Such theories include Tibor Gánti’s chemoton theory, Humberto Maturana and Francisco Varela’s theory of autopoiesis, Robert Rosen’s metabolism-repair (M,R) systems, Stuart Kauffman’s theory of autocatalytic sets, and Karl Friston’s free-energy principle. Central to these theories is an emphasis on metabolic self-production and adaptive self-regulation as the protypical characteristics of life. Combining this approach with biopsychism results in the thesis that all and only metabolically self-producing and adaptively self-regulating systems are sentient. A few biologists (notably, the late Lynn Margulis) have argued for this form of biopsychism. The philosopher Hans Jonas argued for it in The Phenomenon of Life (1966). I come close to advocating it in my book, Mind in Life (2007).
In this paper, I will formulate what I take to be the strongest current argument in favour of biopsychism and critically assess it. Central to this argument is both the insistence on not separating sentience, individuality, and agency (contrary to panpsychism), and the proposition that individuality and agency, which are instantiated already by minimal life, entail sentience. If these claims are correct, animal (metazoan) sentience is only one biological version of sentience. If these claims are incorrect, they may nonetheless be instructive in helping to narrow down the minimal requirements for sentience.

Christof Koch (Allen Institute for Brain Science)
I abduce the existence of conscious states in other humans as an inference to the best explanation of the facts. The same principles can be applied to other mammals, for their behavior and their brains are similar to mine and, mutatis mutandis, to species such as corvids, cephalopods or insects, that are quite different. These abductions are fully compatible with Integrated Information Theory, raising the possibility that consciousness is a property of all complex biological systems, down to single cell organisms.

Jonathan Birch (London School of Economics)
Animal sentience is often regarded as an all-or-nothing property, or one that varies along a single dimension such that some animals are simply "more sentient" than others. I argue that animal sentience varies continuously along several dimensions, and I construct a multidimensional framework for characterizing an animal's form of subjective experience. My proposed framework is based on four key dimensions of variation, which I call valence, grain, unity and flow. All four admit continuous variation, allowing us to assign any organism a "sentience profile" locating it with respect to the four dimensions.

Peter Godfrey-Smith (University of Sydney)
Human conscious experience combines a number of features. Objects in our environment are presented through the senses, information from different sensory modalities are integrated, events are marked with value (positive or negative), and we have a sense of our own location and state. It is difficult to work out which of these might be fundamental to subjective experience, which might come before others in plausible evolutionary trajectories, and which might form a tight package of correlated features. We can make progress on these questions by looking at the distribution of subjectivity-relevant features in non-human animals, especially invertebrates.

Jennifer Mather (University of Lethbridge)
Recent research suggests that animals only distantly related to us, such as octopuses, might have sentience. Given that it is difficult to understand their mental states, how do we use criteria for such states as pain and suffering and situations like enrichment and expression of normal behavior to ensure the welfare of animals we know little about and can assume even less? The life history of octopuses is explored to see how criteria for welfare might be used to determine how invertebrates with consciousness might be ensured the best lives possible.