The argument in support of the claim that animals have direct moral status is rather simple. It goes as follows:
- If a being is sentient then it has direct moral status.
- (Most) animals are sentient
- Therefore (most) animals have direct moral status.
“Sentience” refers to the capacity to experience episodes of positively or negatively valenced awareness. Examples of positively valenced episodes of awareness are pleasure, joy, elation, and contentment. Examples of negatively valenced episodes of awareness are pain, suffering, depression, and anxiety.
In support of premise (1), many argue that pain and pleasure are directly morally relevant, and that there is no reason to discount completely the pleasure or pain of any being. The argument from analogy is often used in support of premise (2) (see the discussion of this argument in section I, part C above). The argument from analogy is also used in answering the difficult question of exactly which animals are sentient. The general idea is that the justification for attributing sentience to a being grows stronger the more analogous it is to human beings.
People also commonly use the flaws of indirect theories as a reason to support the claim that animals have direct moral status. Those that believe both that the marginal cases have direct moral status and that indirect theories cannot answer the challenge of the Argument from Marginal Cases are led to support direct theories; those that believe both that such actions as the torture of one’s own cat for fun are wrong and that indirect theories cannot explain why they are wrong are also led to direct theories.