Sentiocentrism, sentio-centrism, or sentientism is an ethical view which places sentient individuals (i.e., basically conscious beings) at the center of moral concern. It posits that all and only sentient beings have intrinsic value and moral standing, thus they are regarded as moral patients, while the rest of the natural world only has instrumental value. Both humans and other sentient individuals have rights and/or interests that must be considered.
Sentiocentrists consider discrimination between sentient beings of different species to be speciesism, an arbitrary discrimination. Coherent sentiocentrist belief respects all sentient beings. Many self-described humanists see themselves as "sentientists" where the term humanism contrasts with theism and does not describe the sole focus of humanist concerns.
History of concept
Utilitarianism accepts sentiocentrism, thus granting all sentient beings moral concern, where sentient beings are those that have the capacity for experiencing positive or negative conscious states. The 18th-century utilitarian philosopher Jeremy Bentham was among the first to argue for sentiocentrism in his Introduction to the Principles of Morals and Legislation, where he made a comparison between slavery and sadism toward humans and non-human animals:
The French have already discovered that the blackness of the skin is no reason why a human being should be abandoned without redress to the caprice of a tormentor [see Louis XIV's Code Noir] ... What else is it that should trace the insuperable line? Is it the faculty of reason, or, perhaps, the faculty of discourse? But a full-grown horse or dog is beyond comparison a more rational, as well as a more conversable animal, than an infant of a day, or a week, or even a month, old. But suppose the case were otherwise, what would it avail? The question is not Can they reason? nor, Can they talk? but, Can they suffer?
— Jeremy Bentham, Introduction to the Principles of Morals and Legislation, (1823), 2nd edition, Chapter 17, footnote
The late 19th- and early 20th-century American philosopher J. Howard Moore, in Better World Philosophy (1899), described every sentient being as existing in a constant state of struggle. He argued that what aids them in their struggle can be called good and what opposes them can be called bad. Moore believed that only sentient beings can make such moral judgements because they are the only parts of the universe which can experience pleasure and suffering. As a result, he argued that sentience and ethics are inseparable and therefore every sentient piece of the universe has an intrinsic ethical relationship to every other sentient part, but not the insentient parts. Moore used the term "zoocentricism" to describe the belief that universal consideration and care should be given to all sentient beings; he believed that this was too difficult for humans to comprehend in their current stage of development.
Other prominent philosophers discussing or defending sentiocentrism include Peter Singer, Tom Regan, and Mary Anne Warren.
Sentiocentrism is a term contained in the Encyclopedia of Animal Rights and Animal Welfare, edited by Marc Bekoff and Carron A. Meaney.
Justification
Peter Singer provides the following justification of sentiocentrism:
The capacity for suffering and enjoying things is a prerequisite for having interests at all, a condition that must be satisfied before we can speak of interests in any meaningful way. It would be nonsense to say that it was not in the interests of a stone to be kicked along the road by a child. A stone does not have interests because it cannot suffer. Nothing that we can do to it could possibly make any difference to its welfare. A mouse, on the other hand, does have an interest in not being tormented, because mice will suffer if they are treated in this way. If a being suffers, there can be no moral justification for refusing to take that suffering into consideration. No matter what the nature of the being, the principle of equality requires that the suffering be counted equally with the like suffering – in so far as rough comparisons can be made – of any other being. If a being is not capable of suffering, or of experiencing enjoyment or happiness, there is nothing to be taken into account. This is why the limit of sentience (...) is the only defensible boundary of concern for the interests of others.
— Peter Singer, Practical Ethics (2011), 3rd edition, Cambridge University Press, p. 50
In line with the above, Utilitarian philosophers such as Singer not only care about the wellbeing of humans, but also about the wellbeing of sentient non-human animals. Utilitarians reject speciesism, the discrimination of individuals on the basis of their species membership. Drawing an analogy between speciesism and other forms of arbitrary discrimination, Peter Singer writes that
Racists violate the principle of equality by giving greater weight to the interests of members of their own race when there is a clash between their interests and the interests of those of another race. Sexists violate the principle of equality by favoring the interests of their own sex. Similarly, speciesists allow the interests of their own species to override the greater interests of members of other species. The pattern is identical in each case.
— Peter Singer, Animal Liberation (2002), 3rd edition, Ecco: New York, p. 9
Gradualism
In the animal kingdom, there is a gradation in the nervous complexity, taking examples from the marine sponges that lack neurons, intestinal worms with ~ 300 neurons or humans with ~ 86 billion. While the existence of neurons is not sufficient to demonstrate the existence of sentience in an animal, it is a necessary condition. Without neurons, there is no place where it can happen (and the fewer the neurons, the lower the maximum capacity for intelligence in an organism).
Gradualist sentiocentrism states that more complex interests deserve more consideration than less complex moral interests. One implication of this premise is that the best interests of a simple organism do not deserve consideration before the non-best interest in a complex organism (e.g., a dog with intestinal worms should be healed even though this results in the death of the parasites). Note that this does not lead to the rejection of interests of complex animals (such as pigs) versus the human desire to feed on them.
This is a vision that expands to areas that are not only relevant to other species, but to uniquely human issues, as is the case on the legalization of abortion. Gradualism poses a greater consideration of the mother against the fetus in question, given that the latter does not have the ability for complex interests in the early stages of gestation. An emblematic case in this debate is the evolutionary biologist Richard Dawkins, who says that "a human embryo in early-stage, without nervous system and presumably lacking pain and fear, could justifiably be afforded less moral protection than an adult pig, which it is clearly well equipped to suffer".
As a fetus progresses they gain sentience until "the majority of neurons are already present in our brains by the time we are born". Since a 9-month fetus is nearing the mother's level of sentience, a sentiocentrist may, therefore, believe that greater rights should be afforded to a 9-month fetus than a 1-month fetus (if any). Late-term abortions should then require much greater justification under the law than a 6-week abortion, which may not require any justification under the law.
For example, "psycho-social" justifications are often viewed as valid reasons for aborting a fetus with little-to-no sentience, but it may take "medical necessity" to justify killing a fetus with a level of sentience approaching that of their mother.
