Jan 21, 2025 Book Review: “The Edge of Sentience” by Jonathan Birch
Jonathan Birch is a philosopher at the London School of Economics who has dedicated significant time and effort to studying sentience and how to identify sentient beings or systems reliably. He was the lead author of a report that advised the UK Government on the sentience of cephalopods and decapod crustaceans as the government developed and passed the Animal Welfare (Sentience) Act of 2022.
Birch has transformed his exploration of sentience and the identification of beings and systems that may be considered sentient into a new book, The Edge of Sentience, published by Oxford University Press. This book serves as a clear introduction to a complex subject and is available for free download as a PDF from the publisher’s website.
WellBeing International is very interested in this book because we currently publish an academic journal called Animal Sentience. This journal follows an Open Peer Commentary format, meaning it publishes target articles on topics related to animal sentience and invites commentaries from a diverse range of experts on each target article. Over the nine years since the journal’s inception, Professor Birch and his colleagues have contributed two target articles and several commentaries to Animal Sentience.
The Edge of Sentience does not solely concentrate on animal sentience; it also examines human cases involving the loss of consciousness, the question of fetal human sentience, and the potential development of sentience in artificial intelligence systems. The book recounts a disturbing case of a human patient who was presumed to be insentient but, upon regaining the ability to communicate, revealed how horrifying it was to be aware of everything happening to her while being unable to express her awareness (and sentience). Birch also describes how, until the 1980s, surgeons often performed surgeries on fetuses and neonates without general anesthesia, as it was deemed too risky. There was a widespread belief that fetuses and non-verbal neonates were insentient. However, research in the 1980s suggested that fetal and neonatal behavior indicated the presence of sentience. Furthermore, surgeries performed under general anesthesia resulted in better postoperative outcomes for these patients.
Birch emphasizes that incorrectly assuming any being is insentient can lead to horrific consequences. He argues that we need an informed, inclusive, and democratic process to evaluate and determine the proportionality of decisions regarding the presence of sentience. Birch introduces what he calls the PARC tests, which stand for “permissibility-in-principle, adequacy, reasonable necessity, and consistency.” These tests are meant to guide decisions about sentience and appropriate public policy responses in cases involving individuals with disorders of consciousness (PODC), human fetuses and embryos, human neural organoids, non-human animals, and artificial intelligence systems. Bioethicist Jonathan Kimmelman in Nature reviews Birch’s book as “a masterclass in public-facing philosophy.” Additionally, you might find Marc Bekoff’s recent interview with Jonathan Birch on The Edge of Sentience insightful.