If the octopus were conscious, what would its consciousness be like? This paper investigates the structure octopus consciousness, if existent, is likely to exhibit. Presupposing that the configuration of an organism’s consciousness is correlated with that of its nervous system, it is unlikely that the structure of the sort of conscious experience that would arise from the highly decentralized octopus nervous system would bear much resemblance to those of vertebrates. In particular, octopus consciousness may not exhibit (...) unity, which has long been assumed to be the normal or default structure of consciousness. The octopus nervous system is characterized by the following features: its three anatomically distinct components have extensive functional autonomy and little intercommunication; much of the sensory processing and motor control routines—that in vertebrates are localized in the brain—take place within the peripheral arm nervous system; and proprioception and somatotopic representation are significantly downplayed. In this paper, I present the octopus as a highly successful biological organism in which it is plausible that the unified model of consciousness does not hold. (shrink)

Why do octopuses matter to philosophy? They matter to the part of philosophy concerned with the mind. To see why, we step back and think about the evolutionary connections between all living things. Biologists think of these relationships in terms of a tree of life. This is a huge tree-like pattern, marking which species are close relatives and which are distantly connected. The vertebrates form one branch of the tree, and that is where we find nearly all the animals with (...) large and complex brains. These include ourselves, other mammals, and birds. In evolutionary terms, these are all cousins. In the huge area of the tree containing other animals, invertebrates, there is only one small branch where we also find large brains. This branch contains the cephalopods – octopuses, cuttlefish, and squid. Large nervous systems evolved separately on these two branches, and nowhere else. Octopuses are a separate experiment in the evolution of the mind. Meeting an octopus is like meeting an intelligent alien. So what did this experiment produce? Here is one thing. The nervous system of an octopus is less centralized than ours. In fact, more than half of the octopus' neurons are not in the animal's central "brain" at all, but in the eight arms. It is as if each arm has a mind of its own. Or perhaps in an octopus we see intelligence without a unified self. (shrink)

In order to argue that cognitive science should be more accepting of explanatory plurality, this paper presents the control of fetching movements in the octopus as an exemplar of a cognitive process that comprises distinct and non-redundant representation-using and non-representational elements. Fetching is a type of movement that representational analyses can normally account for completely—but not in the case of the octopus. Instead, a comprehensive account of octopus fetching requires the non-overlapping use of both representational and non-representational (...) explanatory frameworks. What this need for a pluralistic or hybrid explanation implies is that cognitive science should be more open to using both representational and non-representational accounts of cognition, depending on their respective appropriateness to the type of cognition in question. (shrink)

Mather (2019) has brought together the current empirical research in support of the claim that octopuses possess minds; and the weight of the evidence does appear to support octopus sentience. Being sentient means an organism has welfare concerns, a subjective experience of life that can go well or poorly. Protecting welfare requires knowing what conditions will have a positive or negative impact. Understanding what is in the mind of an octopus will give us valuable insight into what is (...) good for an octopus. (shrink)

This is a poem about my experience with one of my most meaningful patients, a woman with Takotsubo (translated from Japanese as "Octopus Trap") Cardiomyopathy. Also known as "broken heart syndrome," Takotsubo is a rare condition that results from periods of extreme physical and/or emotional stress. This is an account of my patient's story as "heard" through the EKG, and how despite arrival at the correct diagnosis through careful history taking and EKG findings, no measure of science or diagnosis (...) could offer the comfort we could provide by simply listening to her story and affirming her in her grief. (shrink)

This study discusses the mimic octopus’ (Thaumoctopus mimicus) acts of imitation of a banded sea-snake (Laticauda sp.) as an antagonistic response to enemies from a cognitive-semiotic perspective. This mimicry model, which involves very close physical resemblance and highly precise enactment, displays goal-orientedness because the octopus only takes it on when encountering damselfish, a territorial species, and not other sea animals that the octopus has been shown to imitate, such as lionfish and flounders (Norman et al. 2001). Based (...) on theoretical principles and analytic tools from Mitchell’s (1986) typology of deceptive acts, Zlatev’s (2008) Mimesis Hierarchy and Zlatev’s (2018) types and levels of (self-)consciousness, this research raises the possibility that T. mimicus exhibits the following attributes: (i) bodily self-awareness; (ii) cognitive empathy, which builds upon deception and perspective-taking strategies to imagine or project itself into the place of the antagonist; and (iii) capability to reflectively reorganise the standard complete imitation pattern into a partial one in order to optimise its effect, based on conscious visual appraisal of the stimulus position. These capacities would place T. mimicus at the dyadic mimetic level on the Mimesis Hierarchy. For this reason, it is suggested that the name mimic octopus could be replaced by mimetic octopus. (shrink)

This study discusses the mimic octopus’ acts of imitation of a banded sea-snake as an antagonistic response to enemies from a cognitive-semiotic perspective. This mimicry model, which involves very close physical resemblance and highly precise enactment, displays goal-orientedness because the octopus only takes it on when encountering damselfish, a territorial species, and not other sea animals that the octopus has been shown to imitate, such as lionfish and flounders. Based on theoretical principles and analytic tools from Mitchell’s (...) typology of deceptive acts, Zlatev’s Mimesis Hierarchy and Zlatev’s types and levels of consciousness, this research raises the possibility that T. mimicus exhibits the following attributes: bodily self-awareness; cognitive empathy, which builds upon deception and perspective-taking strategies to imagine or project itself into the place of the antagonist; and capability to reflectively reorganise the standard complete imitation pattern into a partial one in order to optimise its effect, based on conscious visual appraisal of the stimulus position. These capacities would place T. mimicus at the dyadic mimetic level on the Mimesis Hierarchy. For this reason, it is suggested that the name mimic octopus could be replaced by mimetic octopus. (shrink)

Most, if not all, philosophers agree that computers cannot learn what words refers to from raw text alone. While many attacked Searle’s Chinese Room thought experiment, no one seemed to question this most basic assumption. For how can computers learn something that is not in the data? Emily Bender and Alexander Koller ( 2020 ) recently presented a related thought experiment—the so-called Octopus thought experiment, which replaces the rule-based interlocutor of Searle’s thought experiment with a neural language model. The (...) Octopus thought experiment was awarded a best paper prize and was widely debated in the AI community. Again, however, even its fiercest opponents accepted the premise that what a word refers to cannot be induced in the absence of direct supervision. I will argue that what a word refers to _is_ probably learnable from raw text alone. Here’s why: higher-order concept co-occurrence statistics are stable across languages and across modalities, because language use (universally) reflects the world we live in (which is relatively stable). Such statistics are sufficient to establish what words refer to. My conjecture is supported by a literature survey, a thought experiment, and an actual experiment. (shrink)

The idea that there can be only one cognitive system within any single given cognitive organism is an established albeit implicit one within cognitive science and related studies of the mind. The firm foothold of this notion is due largely to the immense corpus of empirical evidence for the correlation of a high level of cognitive sophistication with a centralized nervous system. However, it must be pointed out that these findings are sourced in large part from studies on vertebrates. This (...) paper presents a potential counterexample to the notion that only one cognitive system can be realized within any single genuine cognitive organism. This counterexample is the octopus, an invertebrate with what initially appears to be a paradoxical combination of vertebrate-like cognitive and behavioral capacities and a functionally decentralized nervous system. The extensive relegation of sensorimotor processing and control responsibilities to the peripheral nervous system which controls the arms of the octopus raises principled reasons to believe that the octopus is an organism that may house multiple independent cognitive systems. (shrink)

Jean Painlevé’s films blend aesthetic concerns and scientific realism operating a micro-turn within the broader cinematographic turn that occurred in the sciences in the 20th century. By engaging with his films on the octopus, an animal studied to illuminate human consciousness and firmly grounded in the popular imagina-tion through literature and the arts, this article demonstrates how Painlevé em-braced a politics of life organised around the concept of a missed encounter be-tween life forms.

What is it like to be an octopus, one of those eight-armed, infinitely flexible sea creatures with a nervous system distributed over head, eyes and arms? One interesting approach is to argue that octopuses, because of their distributed nervous systems, are likely to possess disunified consciousness (Carls-Diamante 2017). However, this supposed isomorphism between a “unified” nervous system and “unified” consciousness is problematic, since the term “unity” is taken as a “given” even though it is far from clear what it (...) means. I will argue that explaining the structure of consciousness requires a prior explanation in terms of how it is achieved by the organism through sensorimotor integration. On this account, the structure of an organism’s consciousness is explained partly by what the external world is like, and partly by how the organism’s body, senses and nervous system enable the organism to interact with the external world. (shrink)

The organic unity between the head and the vital arms of the octopus is proposed as a metaphor for science and religion as an academic field. While the specific object of the field is to pursue second-order reflections on existing and possible relations between sciences and religions, it is argued that several aspects of realism and normativity are constitutive to the field. The vital arms of the field are related to engagements with distinctive scientific theories, specialized philosophy of science, (...) representative theological proposals, and the input from the study of world religions. (shrink)

Octopuses are highly intelligent animals with vertebrate-like cognitive and behavioural repertoires. Despite these similarities, vertebrate-based models of cognition and behaviour cannot always be successfully applied to octopuses, due to the structural and functional characteristics that have evolved in their nervous system in response to the unique challenges posed by octopus morphology. For instance, the octopus brain does not support a _somatotopic_ or point-for-point spatial map of the body—an important feature of vertebrate nervous systems. Thus, while octopuses are capable (...) of motor tasks whose vertebrate counterparts require detailed interoceptive monitoring, these movements may not be explainable using motor control frameworks premised on internal spatial representation. One such motor task is the extension of a single arm. The ability of octopuses to select and use a single arm without the guidance of a somatotopic map has been regarded as a motor control puzzle. In an attempt at a solution, this paper develops a predictive processing account of single-arm extension in octopuses. (shrink)

We present a mathematical model of two competing marine species that are harvested. We consider three models according to different levels of complexity, without and with species refuge and density-independent and density-dependent species movement between fishing area and refuge. We particularly study the effects of the fishing pressure on the outcome of the competition. We focus on conditions that allow an inferior competitor to invade as a result of fishing pressure. The model is discussed in relationship to the case of (...) the thiof and the octopus along the Atlantic West African coast. At the origin, the thiof was abundant and the octopus scarce in that region. Since, the fishing pressure has strongly increased in some fishing areas leading to the depletion of the thiof and the invasion of its competitor, the octopus. (shrink)

In her essay “The Idea of Perfection,” Iris Murdoch argues that sustained attention directed towards another can result in a person’s moral improvement by getting them to have a more accurate view of the other. In this essay, I argue that the award-winning film My Octopus Teacher illustrates Murdoch’s view and corrects some of its shortcomings. It illustrates Murdoch’s claim by showing how one of the filmmaker’s sustained attention directed at an octopus results not only in an alternation (...) in the filmmaker’s view of the cephalopod but also transforms his life by making him more open to others. Because the central relationship in the film is one between a human being and a cephalopod, the film also corrects the anthropocentric bias in Murdoch’s account by showing that a human being can have a transformative relationship with a creature as alien appearing as an octopus. (shrink)

The domestic spaces of the built environment are traditionally associated with residential architecture. But the domestic spaces can also extend out, metaphorically, into familiar public spaces in which one may feel at home, and also extend inwards into self-perception, insofar as you may say that you dwell within yourself. This article begins by recalling Vitruvius’ fundamental notion of architectural utilitas concerns accommodating not a building’s owners but foreigners and strange outsiders. Vitruvius’ view on utility heavily favoured architecture’s socio-political function, and (...) the guests he believed that architecture ought to accommodate were not merely a home’s owners or their visiting friends, but those people who are more distant from a home’s owners: those who are stranger and less well understood, known as xenos and who ought to be respected under the Ancient Greek religious and ethical principle of xenia. It is on these grounds that Vitruvius makes an ethical critique of residential architecture in favour of the virtue of public architecture. Next the reach of xenia is proposed to extend towards those who are different not merely because of ethnic differences but cognitive and sensory differences. Such accommodations are today accounted for as part of accessibility design and salutogenic design. Similar conceptions are noted in Nietzsche’s notion of an “architecture for the perceptive” and the surrealist’s interpretation of the minotaur as a hybrid not only of animal and human but a hybrid of civilised citizen and barbarian outsider. Together these sketch out an expanded sense of the domestic that includes public spaces designed to accommodate strange outsiders and the hybrid forms used to signify them. (shrink)

A visionary journey through contemporary scientific concepts and the mysteries and enigmas that define our universe. Examines animal intelligences within a greater evolutionary context, detailing in particular the remarkable intelligence of crows and octopuses. Looks at the Australian Aborigine Dreamtime as an attempt to understand the combined geological and geomantic landscape. Investigates a range of ideas as they relate to the intersections of consciousness and reality, including reincarnation, past-life memories, ghosts, and UFOs.

Conference Report on ASSC 11, Las Vegas 2007.

This chapter contains sections titled: The Extent of the Problem Collections of Fragments The Reporter's Own Agenda Cicero and Epicurus: The Atomic Swerve Importing Distinctions: Dicaearchus on the Soul, Plutarch on the Octopus The Debate about Happiness Mistakes and Misrepresentations, Simple and Less Simple Conclusion Bibliography.

Is a human more conscious than an octopus? In the science of consciousness, it’s oftentimes assumed that some creatures (or mental states) are more conscious than others. But in recent years, a number of philosophers have argued that the notion of degrees of consciousness is conceptually confused. This paper (1) argues that the most prominent objections to degrees of consciousness are unsustainable, (2) examines the semantics of ‘more conscious than’ expressions, (3) develops an analysis of what it is for (...) a degreed property to count as degrees of consciousness, and (4) applies the analysis to various theories of consciousness. I argue that whether consciousness comes in degrees ultimately depends on which theory of consciousness turns out to be correct. But I also argue that most theories of consciousness entail that consciousness comes in degrees. (shrink)

Consciousness has an important role in ethics: when a being consciously experiences the frustration or satisfaction of its interests, those interests deserve higher moral priority than those of a behaviourally similar but non-conscious being. I consider the relationship between this ethical role and an a posteriori (or “type-B”) materialist solution to the mind-body problem. It is hard to avoid the conclusion that, if type-B materialism is correct, then the reference of the concept of phenomenal consciousness is radically indeterminate between a (...) neuronal-level property that is distinctive to mammals and a high-level functional property that is much more widely shared. This would leave many non-mammalian animals (such as birds, fish, insects and octopuses) with indeterminate moral status. There are ways to manage this radical moral indeterminacy, but all of these ways lead to profoundly troubling consequences. (shrink)

Sentience is the capacity to have feelings, such as feelings of pain, pleasure, hunger, thirst, warmth, joy, comfort and excitement. It is not simply the capacity to feel pain, but feelings of pain, distress or harm, broadly understood, have a special significance for animal welfare law. Drawing on over 300 scientific studies, we evaluate the evidence of sentience in two groups of invertebrate animals: the cephalopod molluscs or, for short, cephalopods (including octopods, squid and cuttlefish) and the decapod crustaceans or, (...) for short, decapods (including crabs, lobsters and crayfish). We also evaluate the potential welfare implications of current commercial practices involving these animals. (shrink)

In this essay, I discuss Dennett’s From Bacteria to Bach and Back: The Evolution of Minds and Godfrey Smith’s Other Minds: The Octopus and The Evolution of Intelligent Life from a methodological perspective. I show that these both instantiate what I call ‘synthetic philosophy.’ They are both Darwinian philosophers of science who draw on each other’s work. In what follows I first elaborate on synthetic philosophy in light of From Bacteria and Other Minds; I also explain my reasons for (...) introducing the term; and I close by looking at the function of Darwinism in contemporary synthetic philosophy. (shrink)

How consciousness appeared much earlier in evolutionary history than is commonly assumed, and why all vertebrates and perhaps even some invertebrates are conscious. How is consciousness created? When did it first appear on Earth, and how did it evolve? What constitutes consciousness, and which animals can be said to be sentient? In this book, Todd Feinberg and Jon Mallatt draw on recent scientific findings to answer these questions—and to tackle the most fundamental question about the nature of consciousness: how does (...) the material brain create subjective experience? After assembling a list of the biological and neurobiological features that seem responsible for consciousness, and considering the fossil record of evolution, Feinberg and Mallatt argue that consciousness appeared much earlier in evolutionary history than is commonly assumed. About 520 to 560 million years ago, they explain, the great “Cambrian explosion” of animal diversity produced the first complex brains, which were accompanied by the first appearance of consciousness; simple reflexive behaviors evolved into a unified inner world of subjective experiences. From this they deduce that all vertebrates are and have always been conscious—not just humans and other mammals, but also every fish, reptile, amphibian, and bird. Considering invertebrates, they find that arthropods (including insects and probably crustaceans) and cephalopods (including the octopus) meet many of the criteria for consciousness. The obvious and conventional wisdom–shattering implication is that consciousness evolved simultaneously but independently in the first vertebrates and possibly arthropods more than half a billion years ago. Combining evolutionary, neurobiological, and philosophical approaches allows Feinberg and Mallatt to offer an original solution to the “hard problem” of consciousness. (shrink)

The elephant in the room -- Crabs and octopuses -- The central intelligence of a frog -- The cerebral cortex and consciousness -- Social consciousness -- Yoda and Darth: how can we find -- Consciousness in the brain? -- The hard problem and other perspectives on consciousness -- Conscious machines -- Uploading minds -- How to build visual consciousness.

Daniel Greco (forthcoming) argues that there cannot be epistemic dilemmas. I argue that he is wrong. I then look in detail at a would-be epistemic dilemma and argue that no non-dilemmic approach to it can be made to work. Along the way, there is discussion of octopuses, lobsters, and other ‘inscrutable cognizers’; the relationship between evaluative and prescriptive norms; a failed attempt to steal a Brueghel; epistemic and moral blame and residue; an unbearable guy who thinks he’s God’s gift to (...) women; excuses; stupid games involving hats; radical permissivism; how I’ll never be able to afford to buy a house in Hampstead; and many other exciting topics. (shrink)

Philosophical attention to animals can be found in a wide range of texts throughout the history of philosophy, including discussions of animal classification in Aristotle and Ibn Bâjja, of animal rationality in Porphyry, Chrysippus, Aquinas and Kant, of mental continuity and the nature of the mental in Dharmakīrti, Telesio, Conway, Descartes, Cavendish, and Voltaire, of animal self-consciousness in Ibn Sina, of understanding what others think and feel in Zhuangzi, of animal emotion in Śāntarakṣita and Bentham, and of human cultural uniqueness (...) in Xunzi. In recent years, there has been increased attention to animal minds in philosophical discussions across many areas of metaphysics, epistemology, and value theory. Given that nonhuman animals share some biological and psychological features with humans, and that we share community, land, and other resources, consideration of nonhuman animals has much to contribute to our philosophical activities. -/- Contemporary philosophy of animal minds often also engages with the sciences of animal cognition and behavior. The science of comparative cognition is a thriving area of research, complementing the philosophical study in two ways. For one, philosophers of animal cognition can use claims resulting from animal cognition studies as premises in philosophical discussions. For example, Jacob Beck (2012) relies on pigeons’ abilities to compare quantities to argue for nonconceptual content; Sidney Carls-Diamante (forthcoming) appeals to octopus behavior and physiology to defend embodied cognition; Richard Moore (2016a) refers to ape gestural communication to rethink the requirements for intentional communication; Andrew Barron and Colin Klein (2016) appeal to insect cognition research to defend new theories of consciousness; Sarah Vincent, Rebecca Ring, and Kristin Andrews (2019) cite dolphins’ social practices to argue for the existence of norms that do not require metacognition. -/- In addition, philosophers of animal cognition can examine the epistemology and methods used to justify the claims that arise from the science. Research into animal cognition has resulted in surprising claims about animal capacities, such as sociality in garter snakes (Skinner & Miller 2020), tool-use in ants (Maák et al. 2017), mirror self-recognition in fish (Kohda et al. 2019), empathy in rats (Bartal et al. 2011), social learning in fruit flies (Danchin et al. 2018), episodic memory in dogs (Fugazza et al. 2020), addition and subtraction in bees (Howard et al. 2019). How should we evaluate such claims? -/- Some philosophers have argued that animal cognition research is held to a higher standard than human cognition research, and that scientists working with animals are sometimes asked to solve skeptical problems (Halina 2015). Others have challenged scientific assumptions about the relationship between brain size and intelligence, as well as biases against invertebrates (Mikhalevich & Powell 2020). -/- Animal cognition research challenges philosophers to consider that many capacities and behaviors often assumed to require language, sophisticated technological capacities, or legal systems may in fact be had by other animals who lack these properties. In this way, animal cognition research often surprises us by showing that sophisticated-looking activity can be caused through rather simple mechanisms. -/- 1. What is Animal Cognition? 2. Philosophical Assumptions in the Study of Animal Cognition 2.1 Theory-ladenness 2.2 Value-ladenness 2.3 Objectivity 2.4 Simplicity 2.5 Summary 3. Animal Cognition Applied to Philosophy 3.1 The problem of other minds 3.2 The mind-body problem 3.3 Consciousness 3.4 Thought 3.5 Communication 3.6 Social understanding 3.7 The influence of animal cognition on value theory 3.7.1 Ethics 3.7.2 Political theory 3.8 Summary Bibliography Academic Tools Other Internet Resources Related Entries. (shrink)

Behavioural evidence suggests that cephalopod molluscs may have a form of primary consciousness. First, the linkage of brain to behaviour seen in lateralization, sleep and through a developmental context is similar to that of mammals and birds. Second, cephalopods, especially octopuses, are heavily dependent on learning in response to both visual and tactile cues, and may have domain generality and form simple concepts. Third, these animals are aware of their position, both within themselves and in larger space, including having a (...) working memory of foraging areas in the recent past. Thus if using a ‘global workspace’ which evaluates memory input and focuses attention is the criterion, cephalopods appear to have primary consciousness. (shrink)

This book attempts to advance Donald Griffin's vision of the "final, crowning chapter of the Darwinian revolution" by developing a philosophy for the science of animal consciousness. It advocates a Darwinian bottom-up approach that treats consciousness as a complex, evolved, and multidimensional phenomenon in nature rather than a mysterious all-or-nothing property immune to the tools of science and restricted to a single species. -/- The so-called emergence of a science of consciousness in the 1990s has at best been a science (...) of human consciousness. This book aims to advance a true Darwinian science of consciousness in which its evolutionary origin, function, and phylogenetic diversity are moved from the field’s periphery to its very centre, thus enabling us to integrate consciousness into an evolutionary view of life. Accordingly, this book has two objectives: (i) to argue for the need and possibility of an evolutionary bottom-up approach that addresses the problem of consciousness in terms of the evolutionary origins of a new ecological lifestyle that made consciousness worth having and (ii) to articulate a thesis and beginnings of a theory of the place of consciousness as a complex evolved phenomenon in nature that can help us to answer the question of what it is like to be a bat, an octopus, or a crow. -/- A Philosophy for the Science of Animal Consciousness will appeal to researchers and advanced students interested in advancing our understanding of animal minds as well as anyone with a keen interest in how we can develop a science of animal consciousness. (shrink)

All animals have evolved solutions to manage their genomes, enabling the efficient organization of meters of DNA strands in the nucleus and allowing for nuanced regulation of gene expression while keeping transposable elements suppressed. Epigenetic modifications are central to accomplishing all these. Recent advances in sequencing technologies and the development of techniques that profile epigenetic marks and chromatin accessibility using reagents that can be used in any species has catapulted epigenomic studies in diverse animal species, shedding light on the multitude (...) of epigenomic mechanisms utilized across the evolutionary tree. Now, comparative epigenomics is a rapidly growing field that is uncovering mechanistic aspects of epigenetic modifications and chromatin organization in non‐model invertebrates, ranging from octopus to sponges. This review puts recent discoveries in the epigenetics of non‐model invertebrates in historical context, and describes new insight into the patterning and functions of DNA methylation and other highly conserved epigenetic modifications. (shrink)

Consider what the brain-state theorist has to do to make good his claims. He has to specify a physical–chemical state such that any organism (not just a mammal) is in pain if and only if (a) it possesses a brain of suitable physical–chemical structure; and (b) its brain is in that physical–chemical state. This means that the physical–chemical state in question must be a possible state of a mammalian brain, a reptilian brain, a mollusc’s brain (octopuses are mollusca, and certainly (...) feel pain), etc. At the same time, it must not be a possible (physically possible) state of the brain of any physically possible creature that cannot feel pain. Even if such a state can be found, it must be nomologically certain that it will also be a state of the brain of any extraterrestrial life that may be found that will be capable of feeling pain before we can even entertain the supposition that it may be pain. It is not altogether impossible that such a state will be found... . But this is certainly an ambitious hypothesis. (Putnam 1967/1975, p. 436) The belief that mental states are multiply realized is now nearly universal among philosophers, as is the belief that this fact decisively refutes the identity theory. I argue that the empirical support for multiple realization does not justify the confidence that has been placed in it. In order for multiple realization of mental states to be an objection to the identity theory, the neurological differences among pains, for example, must be such as to guarantee that they are of distinct neurological kinds. But the phenomena traditionally cited do not provide evidence of that sort of variation. In particular, examples of neural plasticity do not provide such evidence. (shrink)