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Multiple Ways To Implement And Infer Sentience, Nicolas Rouleau, Michael Levin Jul 2023

Multiple Ways To Implement And Infer Sentience, Nicolas Rouleau, Michael Levin

Animal Sentience

Segundo-Ortin & Calvo’s (S&C’s) thorough review of “plant neurobiology” presents evidence supporting the possibility of plant sentience. They make a compelling case that plants anticipate, assess risk, cooperate, mimic, and pursue goals, as do their animal counterparts. S&C point out that there is a double standard: behavioural patterns associated with subjective experiences in humans are considered valid for inferring cognition in non-human animals but not in diverse other systems including plants. We argue that cognitive functions, including sentience, can potentially be achieved by very different systems and their disparate substrates. We offer some context from the basal cognition literature and …


Limits To Sentience, Donald M. Broom Jun 2023

Limits To Sentience, Donald M. Broom

Animal Sentience

There are many parallels between cellular function in animals and plants. Plants can have complex interactions with their environments. But they lack a central nervous system, which is a prerequisite for sentience (the capacity to feel). In my view the suggestion that plants are sentient is not only empirically incorrect but potentially harmful to the efforts to protect the welfare of sentient beings.


Plant Sentience: Getting To The Roots Of The Problem, Krzysztof Dolega, Savannah Siekierski, Axel Cleeremans May 2023

Plant Sentience: Getting To The Roots Of The Problem, Krzysztof Dolega, Savannah Siekierski, Axel Cleeremans

Animal Sentience

Segundo-Ortin’s (2023) target article invites us to consider the possibility that plants can experience subjectively felt states. We discuss this speculation on the basis of the functional neurobiology of consciousness. We suggest that demonstrating plant sentience would require that we identify not only behaviors analogous to those exhibited by sentient creatures, but also the functional analogues of the mechanisms causing such behaviors. The lack of clear evidence for any kind of integration between self-states, self-movement, environmental states, memory, or affective communication within plants suggests that plant sentience remains an admittedly fascinating, but ultimately merely provocative speculation.


Dissociation Between Conscious And Unconscious Processes As A Criterion For Sentience, Ivan Ivanchei, Nicolas Coucke, Axel Cleeremans May 2023

Dissociation Between Conscious And Unconscious Processes As A Criterion For Sentience, Ivan Ivanchei, Nicolas Coucke, Axel Cleeremans

Animal Sentience

Based on the literature on human consciousness, we suggest that to demonstrate sentience in a system, one needs to demonstrate both conscious and unconscious processing in the system. Major theories of consciousness require the existence of both conscious and unconscious processes. Contrasting effects of conscious and unconscious processes have been successfully used in human studies and have begun being applied in animal sentience research as well.


Disentangling Sentience From Developmental Plasticity, Jonathan Birch May 2023

Disentangling Sentience From Developmental Plasticity, Jonathan Birch

Animal Sentience

Plants, like animals, display remarkable developmental plasticity, inviting the metaphorical use of terms like “decision” and “choice”. In the animal case, this is not taken to be evidence of sentience, because sentience is a complex product of development, not something that guides it. We should apply the same standards when evaluating the evidence in plants. It is hard to overstate the contrast with the case of invertebrates such as octopuses, where pain markers that were originally developed for use in mammals have been clearly demonstrated and plausible neural substrates for sentience have been identified.


Do Plants Have The Cognitive Complexity For Sentience?, Ricard V. Solé May 2023

Do Plants Have The Cognitive Complexity For Sentience?, Ricard V. Solé

Animal Sentience

Are plants sentient? Like other aspects of the cognitive potential of plants, this is a controversial issue, often driven by analogies and seldom supported on solid theoretical grounds. Sentience is understood in cognitive sciences as the capacity to feel. I suggest that because of plants’ evolved adaptations to morphological plasticity, sessile nature and ecological constraints, they are unlikely to have the requisite cognitive complexity for sentience.


Sensing Is A Far Cry From Sentience, Antonio Damasio, Hanna Damasio Apr 2023

Sensing Is A Far Cry From Sentience, Antonio Damasio, Hanna Damasio

Animal Sentience

The hypothesis that plants might be sentient confuses the notion of sentience (or consciousness) with that of sensing. Sentience/consciousness implies feeling, experience, and subjectivity. Sensing does not. Plants can sense/detect and even respond appropriately in the absence of any sentience/consciousness.


Plant Sentience: The Burden Of Proof, Jon Mallatt, David G. Robinson, Michael R. Blatt, Andreas Draguhn, Lincoln Taiz Apr 2023

Plant Sentience: The Burden Of Proof, Jon Mallatt, David G. Robinson, Michael R. Blatt, Andreas Draguhn, Lincoln Taiz

Animal Sentience

Segundo-Ortin & Calvo’s (2023) target article takes a less speculative and more evidence-based approach to plant sentience than did previous works promoting that idea. However, it retains many of the idea’s longstanding difficulties such as starting from a false dichotomy (plants must be either hardwired or sentient), not accepting the full burden of proof for an extraordinary claim, confusingly redefining accepted cognitive terms, implying cell consciousness, not adopting the most parsimonious explanations for plant behaviors, and downplaying all the counterevidence. We advise rectifying these problems before plant sentience can become a full-fledged scientific domain.


Plants Lack The Functional Neurotransmitters And Signaling Pathways Required For Sentience In Animals, David G. Robinson, Michael R. Blatt, Andreas Draguhn, Lincoln Taiz, Jon Mallatt Apr 2023

Plants Lack The Functional Neurotransmitters And Signaling Pathways Required For Sentience In Animals, David G. Robinson, Michael R. Blatt, Andreas Draguhn, Lincoln Taiz, Jon Mallatt

Animal Sentience

We cannot agree with Segundo-Ortin and Calvo that plants are sentient organisms. We have critically examined several aspects of their target article, and find their claims are not supported by the published evidence. We address these claims in sections on whether plants have a ‘neurobiology’ analogous to that of animal nervous systems, including neurotransmitters and synaptic receptors that respond to anesthetics; and whether plant signaling resembles neural transmission. For the latter, we especially consider the unique way plants signal their responses to wounding. Although the plant vascular system has been compared to the animal nervous system, animal blood vessels would …


Questions About Sentience Are Not Scientific But Cultural, Yoram Gutfreund Apr 2023

Questions About Sentience Are Not Scientific But Cultural, Yoram Gutfreund

Animal Sentience

Abstract: The findings of complex cognitive-like behaviours in plants are surprising and exciting. However, they do not provide a scientific reason for ascribing sentience to plants. The target article, in trying to provide evidence for sentience in plants, exposes the weakness of the science of animal consciousness in general. In this commentary, I try to explain why the scientific method is incapable of resolving the question of which organisms or systems are sentient.


Plant Sentience Revisited: Sifting Through The Thicket Of Perspectives, Paco Calvo, Miguel Segundo-Ortin Jan 2023

Plant Sentience Revisited: Sifting Through The Thicket Of Perspectives, Paco Calvo, Miguel Segundo-Ortin

Animal Sentience

In our target article (Segundo-Ortin & Calvo 2023), we proposed the intriguing possibility of plant sentience, drawing parallels with non-human animal studies. This response aims to sift through the rich thicket of perspectives offered by our commentators. To do so, we assess the risks of employing double standards, as well as the tendencies of anthropomorphizing and zoomorphizing in plant studies. We also emphasize the need for clarity in linguistic and conceptual terms, examine the neurophysiological evidence for plant sentience, and discuss the ethical implications of such recognition.


Defining And Exploring Animal Sentience, Andrew N. Rowan, Joyce M. D'Silva Mrs, Ian J.H. Duncan, Nicholas Palmer Jan 2023

Defining And Exploring Animal Sentience, Andrew N. Rowan, Joyce M. D'Silva Mrs, Ian J.H. Duncan, Nicholas Palmer

Animal Sentience

One of the commentaries on the target article notes that "animal sentience" is difficult to define operationally. This response to the commentaries develops a working, usable definition of animal sentience and examines the relationships between animal emotions and sentience.


Plant Sentience? Between Romanticism And Denial: Science, Miguel Segundo-Ortin, Paco Calvo Jan 2023

Plant Sentience? Between Romanticism And Denial: Science, Miguel Segundo-Ortin, Paco Calvo

Animal Sentience

A growing number of non-human animal species are being seriously considered as candidates for sentience, but plants are either forgotten or explicitly excluded from these debates. In our view, this is based on the belief that plant behavior is hardwired and inflexible and on an underestimation of the role of plant electrophysiology. We weigh such assumptions against the evidence to suggest that it is time to take seriously the hypothesis that plants, too, might be sentient. We hope this target article will serve as an invitation to investigate sentience in plants with the same rigor as in non-human animals.


Fine-Tuning The Criteria For Inferring Sentience, Culum Brown Jan 2022

Fine-Tuning The Criteria For Inferring Sentience, Culum Brown

Animal Sentience

“Sentience” means the capacity to feel, and feelings are private affairs. Sentience is hence extremely difficult to quantify in nonhuman animals. We have no direct means of determining whether an animal is sentient. Thus we rely on a series of indirect measures or criteria which collectively provide some level of confidence about the probability that an animal is sentient. Crump et al. propose a modified framework based on 8 criteria for estimating the likelihood of sentience in a target taxon. Whereas I very much like their proposed framework, I would suggest a couple of amendments that may improve it further: …


Unconscious Humans, Autonomous Machines And The Difficulty Of Knowing Which Animals Are Sentient, Marian Stamp Dawkins Jan 2022

Unconscious Humans, Autonomous Machines And The Difficulty Of Knowing Which Animals Are Sentient, Marian Stamp Dawkins

Animal Sentience

The framework proposed by Crump et al. still leaves much doubt about whether invertebrates such as crabs are sentient. For example, many complex behaviours - even in humans - occur without sentience. Also, simple machines could easily meet all of Crump et al.’s eight proposed criteria for sentience. Acknowledging the limitations of what we currently know about sentience is important both for formulating legislation correctly and for advancing scientific understanding of this most puzzling of biological phenomena.


Animal Sentience Research: Synthesis And Proposals, Andrew Crump, Heather Browning, Alex Schnell, Charlotte Burn, Jonathan Birch Jan 2022

Animal Sentience Research: Synthesis And Proposals, Andrew Crump, Heather Browning, Alex Schnell, Charlotte Burn, Jonathan Birch

Animal Sentience

Most commentaries on our target article broadly support our approach to evaluating evidence of animal sentience. In this Response, we clarify the framework’s purpose and address criticisms of our criteria. A recurring theme is that a framework to synthesise current evidence of sentience is not the same as an agenda for future directions in animal sentience research. Although future directions are valuable, our framework aims to evaluate existing evidence and inform animal welfare legislation.


All Living Organisms Are Sentient, Arthur S. Reber, Frantisek Baluska, William B. Miller Jr. Jan 2022

All Living Organisms Are Sentient, Arthur S. Reber, Frantisek Baluska, William B. Miller Jr.

Animal Sentience

We argue that all living organisms, from the simplest unicellular prokaryotes to Homo sapiens, have valenced experiences—feelings as states of preference—and are capable of cognitive representations. Bacteria can learn, form stable memories, and communicate, hence solve problems. Rowan et al.'s statement that "Subjective feelings are just that — subjective — and are available only to the animal (or human) experiencing them" is true but irrelevant. When we see a fish flopping about in the bottom of a boat we immediately recognize suffering without having a glimpse of the nature of piscine distress. Some controlled anthropomorphism can go a …


Legal Recognition Of Animal Sentience: The Case For Cautious Optimism, Jane Kotzmann Jan 2022

Legal Recognition Of Animal Sentience: The Case For Cautious Optimism, Jane Kotzmann

Animal Sentience

Rowan et al.’s target article provides a valuable indication of the work that was required to reach the point where animals are recognised as sentient in various laws. To ensure this work was not in vain, the language of sentience needs to be used as a moral currency to demand further cultural change involving greater human respect for animals.


The Science Of Animal Sentience And The Politics Of Animal Welfare Should Be Kept Separate, Marian Stamp Dawkins Jan 2022

The Science Of Animal Sentience And The Politics Of Animal Welfare Should Be Kept Separate, Marian Stamp Dawkins

Animal Sentience

Although linked historically by Rowan et al., the scientific study of animal sentience and political campaigns to improve animal welfare should be kept separate, for at least two reasons. First, the separation makes it clear that standards of evidence acceptable for ethical or political decisions on animal welfare can be lower than those required for a rigorously scientific approach to animal sentience. Second, it helps to avoid confirmatory bias in the form of giving undue weight to results that are in line with pre-conceived ideas and political views.


Pain Sentience Criteria And Their Grading, Eva Jablonka, Simona Ginsburg Jan 2022

Pain Sentience Criteria And Their Grading, Eva Jablonka, Simona Ginsburg

Animal Sentience

On the basis of the target article by Crump and colleagues, we suggest a more parsimonious scheme for evaluating the evidence for sentience. Since some of the criteria used by Crump et al. are not independent and some are uninformative we exclude some criteria and amalgamate others. We propose that evidence of flexible learning and prioritization, in conjunction with relevant data on brain organization, is sufficient for assigning pain-sentience to an animal and we suggest a scoring scheme based on four criteria.


Truly Minimal Criteria For Animal Sentience, Mark Solms Jan 2022

Truly Minimal Criteria For Animal Sentience, Mark Solms

Animal Sentience

The criteria for determining animal sentience proposed in the target article are sensible but they lack an explicit functional justification for the focus on pain. This commentary provides an abbreviated account of the most basic functional principles that underpin animal sentience and articulates some minimal criteria for determining its presence.


No Need For Certainty In Animal Sentience, Yew Kwang Ng Jan 2022

No Need For Certainty In Animal Sentience, Yew Kwang Ng

Animal Sentience

This commentary supports Crump et al.’s (2022) point that where risks to welfare are severe, strong evidence of sentience is sufficient to warrant protecting welfare. Crump et al.’s eight criteria for sentience are also useful. Flexible decision-making (5) and flexible behaviour (6) are consistent with Ng (1995). The concession that the “no-need-for-sentience” proposition is unnecessary also strengthens the importance of the target article’s conclusions.


Independence, Weight And Priority Of Evidence For Sentience, Elizabeth Irvine Jan 2022

Independence, Weight And Priority Of Evidence For Sentience, Elizabeth Irvine

Animal Sentience

This commentary maps out relationships of dependency between the criteria proposed in the target article (Crump et al. 2022), identifying the criteria that carry most of the weight of the evidence, and suggesting which criteria should have priority in research on sentience.


Decapod Sentience: Broadening The Framework, Cecilia De Souza Valente Jan 2022

Decapod Sentience: Broadening The Framework, Cecilia De Souza Valente

Animal Sentience

A framework for studying sentience in decapods is of great value, but how high a cost (in suffering) to each individual decapod (or any animal) is warranted for collecting scientific evidence of sentience? The lack of evidence for some of the target article’s proposed criteria surely results from the fact that research is focused mainly on biomedical studies, ecotoxicology, and commercial production, with decapod sentience and welfare seen as only a secondary research topic. I draw attention also to the possibility of a wider framework that includes all felt experiences, from suffering to pleasure.


Sentience In Decapods: Difficulties To Surmount, Michael L. Woodruff Jan 2022

Sentience In Decapods: Difficulties To Surmount, Michael L. Woodruff

Animal Sentience

In the target article Crump et al. present 8 criteria to assess whether decapods experience pain. Four of these -- sensory integration, motivational trade-offs, flexible self-protection, and associative learning -- could be used to assess sentience in general. In this commentary I discuss difficulties with using these criteria to provide evidence of sentience in decapods, particularly if this evidence is to change public opinion and policies. These difficulties are lack of evidence, the potential to eventually explain the neurobiological basis of the behaviors chosen as criteria, thereby eliminating any explanatory work for sentience, and the reluctance to bring animals that …


Generalizing Frameworks For Sentience Beyond Natural Species, Michael Levin Jan 2022

Generalizing Frameworks For Sentience Beyond Natural Species, Michael Levin

Animal Sentience

Crump et al. (2022) offer a well-argued example of an essential development: a rigorous framework for assessing sentience from the perspective of moral concern over an agent’s welfare. Current and forthcoming developments in bioengineering, synthetic morphology, artificial intelligence, biorobotics, and exobiology necessitate an expansion and generalization of this effort. Verbal reports (the Turing Test) and homology to human brains are utterly inadequate criteria for assessing the status of novel, unconventional agents that offer no familiar touchstone of phylogeny or anatomy. We must develop principled approaches to evaluating the sentience of (and thus, our responsibility to) beings of unfamiliar provenance and …


Distinguishing Epistemic And Moral Grounds For Legal Protection, Carlos Montemayor Jan 2022

Distinguishing Epistemic And Moral Grounds For Legal Protection, Carlos Montemayor

Animal Sentience

The criteria proposed by Crump et al. are based on various cognitive roles associated with sentience. A subset of them may be sufficient for certain kinds of welfare, but the presence of all of them should be considered as clearly sufficient for substantial kinds of legal protection based on their relation to capacities that we consider essential for moral standing in human beings.


Strong Inferences About Pain In Invertebrates Require Stronger Evidence, Edgar T. Walters Jan 2022

Strong Inferences About Pain In Invertebrates Require Stronger Evidence, Edgar T. Walters

Animal Sentience

Evidence for sentience in animals distantly related to humans is often sought in observations of behavioral and neural responses to noxious stimuli that would be painful in humans. Most proposed criteria for painful sentience in “lower” animals such as decapod crustaceans have no necessary links to the affective (“suffering”) component of pain. The best evidence for painful affect in animals is learned aversion to stimuli associated with noxious experience, and conditioned preference for contexts associated with relief from aversive consequences of noxious experience, as expressed in voluntary behavior. Such evidence is currently lacking for any invertebrate except octopus.


Emotional Component Of Pain Perception In The Medicinal Leech?, Brian D. Burrell Jan 2022

Emotional Component Of Pain Perception In The Medicinal Leech?, Brian D. Burrell

Animal Sentience

Crump et al. have provided a series of criteria to assess animal sentience that is focused on the perception of pain, which is known to have both sensory and emotional components. They also provide a qualitative scoring system to assess data that address the eight criteria and apply this paradigm to decapod crustaceans. The criteria laid out have the potential to be applied to other invertebrates typically thought to have sensory response to tissue damage, but no emotional component to pain perception.


Does The Sentience Framework Imply All Animals Are Sentient?, Kristin Andrews Jan 2022

Does The Sentience Framework Imply All Animals Are Sentient?, Kristin Andrews

Animal Sentience

The eight criteria proposed in Crump et al.’s framework for evaluating pain sentience in decapod crustaceans are just the tip of the iceberg when it comes to markers that could increase confidence in an animal’s sentience more generally. Some of the commentaries have already pointed out that pain is only one kind of sentience (Souza Valente). It has also already been pointed out that there are other criteria for pain that could be usefully added to the framework’s eight (Burrell). This expansive thinking about criteria that can be used to increase confidence in sentience raisess the question: in an expansive …