Sentience
Sentience is the capacity to feel, perceive, or experience subjectively. Eighteenth-century philosophers used the concept to distinguish the ability to think from the ability to feel. In modern Western philosophy, sentience is the ability to experience sensations. In Eastern philosophy, sentience is a metaphysical quality of all things that require respect and care.
Philosophy and sentience
In the philosophy of consciousness, sentience can refer to the ability of any entity to have subjective perceptual experiences, or as some philosophers refer to them, "qualia". This is distinct from other aspects of the mind and consciousness, such as creativity, intelligence, sapience, self-awareness, and intentionality. Sentience is a minimalistic way of defining consciousness, which otherwise commonly and collectively describes sentience plus other characteristics of the mind. Consciousness may not be necessary for sentience, which rests on the capacity to experience emotion, much of which is generated unconsciously.Some philosophers, notably Colin McGinn, believe that the physical process causing sentience to happen will never be understood, a position known as "new mysterianism". They do not deny that most other aspects of consciousness are subject to scientific investigation but they argue that subjective experiences will never be explained; i.e., sentience is the only aspect of consciousness that cannot be explained. Other philosophers disagree, arguing that all aspects of consciousness will eventually be explained by science.
Recognition paradox and relation to sapience
While it has been traditionally assumed that sentience and sapience are, in principle, independent of each other, there are criticisms of that assumption. One such criticism is about recognition paradoxes, one example of which is that an entity that cannot distinguish a spider from a non-spider cannot be arachnophobic. More generally, it is argued that since it is not possible to attach an emotional response to stimuli that cannot be recognized, emotions cannot exist independently of cognition that can recognize. The claim that precise recognition exists as specific attention to some details in a modular mind is criticized both with regard to data loss as a small system of disambiguating synapses in a module physically cannot make as precise distinctions as a bigger synaptic system encompassing the whole brain, and for energy loss as having one system for motivation that needs some built-in cognition to recognize anything anyway and another cognitive system for making strategies would cost more energy than integrating it all in one system that use the same synapses. Data losses inherent in all information transfer from more precise systems to less precise systems are also argued to make it impossible for any imprecise system to use a more precise system as an "emissary", as a less precise system would not be able to tell whether the outdata from the more precise system was in the interest of the less precise system or not.Empirical data on conditioned reflex precision
The original studies by Ivan Pavlov that showed that conditioned reflexes in human children are more discriminating than those in dogs, human children drooling only at ticking frequencies very close to those at which food was served while dogs drool at a wider range of frequencies, have been followed up in recent years with comparative studies on more species. It is shown that both brain size and brain-wide connectivity contribute to make perception more discriminating, as predicted by the theory of a brain-wide perception system but not by the theory of separate systems for emotion and cognition.Indian religions
Eastern religions including Hinduism, Buddhism, Sikhism, and Jainism recognise non-humans as sentient beings. In Jainism and Hinduism, this is closely related to the concept of ahimsa, nonviolence toward other beings. In Jainism, all matter is endowed with sentience; there are five degrees of sentience, from one to five. Water, for example, is a sentient being of the first order, as it is considered to possess only one sense, that of touch. Man is considered a sentient being of the fifth order. According to Buddhism, sentient beings made of pure consciousness are possible. In Mahayana Buddhism, which includes Zen and Tibetan Buddhism, the concept is related to the Bodhisattva, an enlightened being devoted to the liberation of others. The first vow of a Bodhisattva states: "Sentient beings are numberless; I vow to free them."Sentience in Buddhism is the state of having senses. In Buddhism, there are six senses, the sixth being the subjective experience of the mind. Sentience is simply awareness prior to the arising of Skandha. Thus, an animal qualifies as a sentient being.
Animal welfare, rights, and sentience
In the philosophies of animal welfare and rights, sentience implies the ability to experience pleasure and pain. Additionally, it has been argued, as in the documentary Earthlings:Animal-welfare advocates typically argue that any sentient being is entitled, at a minimum, to protection from unnecessary suffering, though animal-rights advocates may differ on what rights may be entailed by simple sentience. Sentiocentrism describes the theory that sentient individuals are the center of moral concern.
The 18th-century philosopher Jeremy Bentham compiled enlightenment beliefs in Introduction to the Principles of Morals and Legislation, and he included his own reasoning in a comparison between slavery and sadism toward animals:
In the 20th century, Princeton University professor Peter Singer argued that Bentham's conclusion is often dismissed by an appeal to a distinction that condemns human suffering but allows non-human suffering, typically "appeals" that are logical fallacies. Because many of the suggested distinguishing features of humanity—high intelligence; highly complex language; etc.—are not present in marginal cases such as mute humans, young children, deaf humans, and mentally disabled humans, it appears that the only distinction is a prejudice based on species alone, which animal-rights supporters call speciesism—that is, differentiating humans from other animals purely on the grounds that they are human. His opponents accuse him of the same petitio principii.
Gary Francione also bases his abolitionist theory of animal rights, which differs significantly from Singer's, on sentience. He asserts that, "All sentient beings, humans or nonhuman, have one right: the basic right not to be treated as the property of others."
Andrew Linzey, founder of the Oxford Centre for Animal Ethics in England, is known as a foremost international advocate for recognising animals as sentient beings in biblically based faith traditions. The Interfaith Association of Animal Chaplains encourages animal ministry groups to adopt a policy of recognising and valuing sentient beings.
In 1997 the concept of animal sentience was written into the basic law of the European Union. The legally binding protocol annexed to the Treaty of Amsterdam recognises that animals are "sentient beings", and requires the EU and its member states to "pay full regard to the welfare requirements of animals".
The laws of several states include certain invertebrates such as cephalopods and decapod crustaceans in the scope of animal protection laws, implying that these animals are also judged capable of experiencing pain and suffering.