Considering Sentient Beings

What matters in deciding whom we owe consideration is who can be harmed or benefited by our decisions; the capacity to act morally matters for holding someone responsible, not for considering them.

If the lack of certain abilities and relationships in some humans doesn't justify treating them worse, the same lack in animals doesn't either; and it's usually a reason to care more, since it increases vulnerability.

Sentience is the capacity to have positive and negative experiences; it's what makes someone a “someone” rather than a “something,” and so able to be harmed by the presence of what's bad or the absence of what's good.

To find out which beings are sentient, we look at evidence: a centralized nervous system, other physiological indicators, overall behavior, and evolutionary advantage. Many invertebrates meet these criteria, and non-organic sentience is a future possibility.

The principle of equal consideration says that harms and benefits of similar magnitude should have the same weight, whoever they belong to; violating it is speciesism, which isn't limited to exploitation, to total disregard, or to anthropocentrism.

Desert can sometimes change priorities, but only for accountable agents who have broken some rule; since animals aren't accountable, desert doesn't justify giving them less weight.

Rejecting speciesism doesn't require signing on to a specific ethical theory, like utilitarianism: a wide range of theories that disagree about a great deal can agree in condemning the exploitation of animals.

Giving equal consideration to all sentient beings doesn't leave us without guidance for setting priorities: there are several criteria compatible with it, such as prioritizing those who are worse off, the greater number, the greater benefit, or the greater future impact.

More complex cognition doesn't always mean suffering more: sometimes it increases suffering (anticipation), sometimes it reduces it (understanding that a treatment is for your own good); and lesser cognition usually comes with greater vulnerability.

A decision is fair if it's the one we would choose without knowing which position we'd occupy among those affected; not knowing whether we'd be human or animal, we wouldn't accept exploitation or speciesism.

An attitude is speciesist if it's unfair to sentient beings because of their species; we can test it by asking whether we'd keep the decision without knowing the species of those affected, without knowing our own, if the victims were human, or if we switched places.

Faced with “why worry about animals when so many humans need help?”, the chapter shows that, by severity, number of victims, and neglect, the animal cause would deserve very high priority under conditions of impartiality.

When we're uncertain whether a being is sentient, we should give it the benefit of the doubt: err on the side of caution, because treating it as an object, if it does feel, is a more serious mistake than the reverse.