Questions about animal consciousness — in particular, which animals have consciousness and what (if anything) that consciousness might be like — are both scientific and philosophical. They are scientific because answering them will require gathering information using scientific techniques — no amount of arm-chair pondering, conceptual analysis, logic, a priori theory-building, transcendental inference or introspection will tell us whether a platypus, an iguana, or a squid (to take a few examples) enjoy a life of subjective experience — at some point we'll have to learn something about the animals. Just what sort(s) of science can bear on these questions is a live question, but at the least this will include investigations of the behavior and neurophysiology of a wide taxonomic range of animals, as well as the phylogenetic relationships among taxa. But these questions are deeply philosophical as well, with epistemological, metaphysical, and phenomenological dimensions. Progress will therefore ultimately require interdisciplinary work by philosophers willing to engage with the empirical details of animal biology, as well as scientists who are sensitive to the philosophical complexities of the issue.5. The Structure and Function of Consciousness
6. Evolution and Distribution of Consciousness
6.1 Humans
6.2 Great Apes
6.3 Mammals
6.4 Amniotes (including birds and reptiles)
6.5 Vertebrates
7. Special Topics in the Study of Animal Consciousness
7.1 Animal pain and suffering
7.2 Animal emotions
7.3 Perceptual phenomenology
7.4 Mental Time Travel
7.5 Self-consciousness and metacognition
8. Summary
Bibliography
Academic Tools
Other Internet Resources
Related Entries
[size=30]1. Motivations
There are many reasons for philosophical interest in nonhuman animal (hereafter “animal”) consciousness:
First, if philosophy often begins with questions about the place of humans in nature, one way humans have attempted to locate themselves is by comparison and contrast with those things in nature most similar to themselves, i.e., other animals. At least in the West, the traditional — and perhaps still intuitive to many people — way of thinking about consciousness is as primarily an innate endowment of humans, which other animals may or may not share in virtue of being sufficiently like us. Within the traditional Biblical cosmology, while all animals were said to have arisen through divine intentional creation, humans were the only ones created in the likeness of the deity, and thus enjoyed a special, privileged role in the intended workings of the cosmos — including, for example, access to an eternal afterlife not overpopulated with fleas, ants and snails. (See Lewis, 2009 Ch 9 for an in-depth treatment of the problem of animal consciousness in relation to Christian theology.) However, within a modern biological worldview, while humans may be unique in certain (perhaps quite important) respects, we are only one species of animal among many — one tip of one branch of the phylogenetic tree of life, and enjoy no particular special status.
From an evolutionary perspective, consciousness is a trait that some animals have (at least humans have it). Salient questions include: Is it a late evolved, narrowly distributed trait, or an older more broadly shared trait? And, did it evolve only once, or a number of times independently? From this view point, the question “Are (non-human) animals conscious?” is rather strange, because, for example, it implicitly groups bats together with rabbits (as ‘nonhuman’ animals) in contrast to humans. In reality, rabbits are more closely related to humans than they are to bats (Nishihara et al. 2006), so framing the question this way embeds a false presupposition. Of course, it is consistent with an evolutionary perspective that humans are the only conscious animals. This would imply that consciousness was acquired through a recent evolutionary event that occurred since the split of our ancestral lineage from that of our closest non-human relatives, chimpanzees and bonobos (see section 6 for discussion of such hypotheses). But such a view requires support; though perhaps intuitive to some, its choice as a default position is arbitrary.
Second, there is a lot at stake morally in the question of whether animals are conscious beings or “mindless automata”. (See article on the Moral Status of Animals.) Many billions of animals are slaughtered every year for food, use in research, and other human purposes. Moreover, before their deaths, many — perhaps most — of these animals are subject to conditions of life that, if they are in fact experienced by the animals in anything like the way a human would experience them, amount to cruelty. Arguments that non-human animals are not conscious therefore effectively double as apologetics for our treatment of animals. When the question of animal consciousness is under consideration, our guilt or innocence as a civilization for an enormous body of cruelty may hang in the balance. However, some philosophers have argued that consciousness per se does not matter for the treatment of animals, and therefore either that a) even if animals are not conscious, they may deserve moral consideration, or b) even if animals are conscious, they may not deserve moral consideration. (For more discussion of the ethical issues, see Singer 1990 [1975]; Regan 1983; Rollin 1989; Varner 1998, 2012; Steiner 2008.)
Third, while theories of consciousness are frequently developed without special regard to questions about animal consciousness, the plausibility of such theories has sometimes been assessed against the results of their application to animal consciousness (and, similarly, to human infants). This raises questions about the relative epistemic weight of theoretical considerations (e.g. philosophical arguments for a given theory of consciousness) against particular case judgments or intuitions about whether a given creature is conscious. For example, Searle (1998) argues that our intuitive, commonsense attributions of intentional and emotional states to dogs carries more epistemic weight than philosophically motivated skeptical concerns. In contrast, Carruthers (1989) asserts that his own arguments that nonhuman animals (even dogs) lack consciousness are sufficiently weighty that we are morally obligated to eradicate or ignore our sympathetic feelings toward such creatures. Should our theories of consciousness be constrained by our intuitive attributions of consciousness to animals (or, e.g., babies), or should the former override the latter?
Fourth, the problem of determining whether animals are conscious stretches the limits of knowledge and scientific methodology (beyond the breaking point, according to some). The so-called “cognitive revolution” that took place during the latter half of the 20th century has led to many innovative experiments by comparative psychologists and ethologists probing the cognitive capacities of animals. The philosophical issues surrounding the interpretation of experiments to investigate perception, learning, categorization, memory, spatial cognition, numerosity, communication, language, social cognition, theory of mind, causal reasoning, and metacognition in animals are discussed in the entry on
animal cognition. Despite this work on cognition, the topic of consciousness per se in animals has remained controversial, even taboo, among many scientists, while other scientists from a variety of disciplinary backgrounds (e.g. neuroscience, animal behavior, evolutionary biology) have developed novel ways of approaching the subject (see Boly et al. 2013 for a review). The 2012
Cambridge Declaration on Animal Consciousnessindicates that many scientists agree that “the weight of evidence indicates that humans are not unique in possessing the neurological substrates that generate consciousness.” However, other scientists, including Marian Stamp Dawkins, who has been prominent in the science of animal welfare (Dawkins 1985, 1993), are not ready to endorse the claim, writing that, “The mystery of consciousness remains. The explanatory gap is as wide as ever and all the wanting in the world will not take us across it” (Dawkins 2012, pp. 171–172).
Many philosophers and scientists have either argued or assumed that consciousness is inherently private, and hence that one's own experience is unknowable to others. While language may allow humans to cross this supposed gap by communicating their experience to others, this is allegedly not possible for other animals. Despite the controversy in philosophical and scientific circles, it remains a matter of common sense to most people that some animals do have conscious experiences. Most people, if asked why they think familiar animals such as their pets are conscious, would point to similarities between the behavior of those animals and human behavior — for example, animals seem to visibly express pleasure and displeasure and a variety of emotions, their behavior seems to be motivated by seeking food, comfort, social contact, etc., they seem aware of their surroundings and able to learn from experience. Similarity arguments for animal consciousness thus have roots in common sense observations. But they may also be bolstered by scientific investigations of behavior and the comparative study of brain anatomy and physiology, as well as considerations of evolutionary continuity between species. Neurological similarities between humans and other animals have been taken to suggest commonality of conscious experience; all mammals share the same basic brain anatomy, and much is shared with vertebrates more generally. Even structurally different brains may be neurodynamically similar in ways that enable inferences about animal consciousness to be drawn (Seth
et al. 2005).
As well as generic arguments about the connections among consciousness, neural activity, and behavior, a considerable amount of scientific research directed towards understanding particular conscious states uses animals as proxies for humans. The reactions of many animals, particularly other mammals, to bodily events that humans would report as painful are easily and automatically recognized by most people as pain responses. High-pitched vocalizations, fear responses, nursing of injuries, and learned avoidance are among the responses to noxious stimuli that are all part of the common mammalian heritage, and similar responses are also observable in organisms from a wide range of taxonomic groups (see section 7.1 below).
Much of the research that is of direct relevance to the treatment of human pain, including on the efficacy of analgesics and anesthetics, is conducted on rats and other animals. The validity of this research depends on the similar mechanisms involved
[1] and to many it seems arbitrary to deny that injured rats, who respond well to opiates for example, feel pain.
[2] Likewise, much of the basic research that is of direct relevance to understanding human visual consciousness has been conducted on the very similar visual systems of monkeys. Monkeys whose primary visual cortex is damaged even show impairments analogous to those of human blindsight patients (Stoerig & Cowey 1997) suggesting that the visual consciousness of intact monkeys is similar to that of intact humans. Scientific demonstrations that members of other species, even of other phyla, are susceptible to the same visual illusions as we are (e.g., Fujita
et al. 1991) suggesting that their visual experiences are similar.
It is often argued that the use of animals to model neuropsychiatric disorders presupposes convergence of emotional and other conscious states and further refinements of those models may strengthen the argument for attributing such states to animals. An interesting reversal of the modeling relationship can be found in the work of Temple Grandin, Professor of Animal Science at Colorado State University, who uses her experience as a so-called “high-functioning autistic” as the basis for her understanding of the nature of animal experience (Grandin 1995, 2004).
Such similarity arguments are, of course, inherently limited in that it is always open to critics to exploit some
disanalogy between animals and humans to argue that the similarities don't entail the conclusion that both are sentient. Even when bolstered by evolutionary considerations of continuity between the species, the arguments are vulnerable, for the mere fact that humans have a trait does not entail that our closest relatives must have that trait too. There is no inconsistency with evolutionary continuity to maintain that only humans have the capacity to learn to play chess. Likewise for consciousness. Povinelli & Giambrone (2000) also argue that the argument from analogy fails because superficial observation of quite similar behaviors even in closely related species does not guarantee that the underlying cognitive principles are the same, a point that Povinelli believes is demonstrated by his research into how chimpanzees use cues to track visual attention (Povinelli 1996).
Perhaps a combination of behavioral, physiological and morphological similarities with evolutionary theory amounts to a stronger overall case
[3]. However, a convincing argument will likely also require motivation in terms of a well developed theory of the structure and function of consciousness as a cognitive process — a route that many recent participants in the debate on animal consciousness have pursued (see section 6).[/size]
الثلاثاء مارس 08, 2016 3:20 am من طرف free men