Moral status of animals in the ancient world

Records from as early as the 6th century before the common era (BCE) include discussions of animal ethics in Jain and Greek texts.

The earliest reference to the idea of non-violence to animals (pashu-ahimsa), apparently in a moral sense, is in the Hindu text of Kapisthala Katha Samhita of the Yajurveda (KapS 31.11), written about the 8th century BCE.

Failing to observe the duty to care could lead to bad karma, which increased the likelihood of returning as an animal next time round.

Psychologist Richard Ryder, former Mellon Professor at Tulane University and chairman of the RSPCA in 1977, writes that it is in 6th century BCE Greek philosophy that we first find concern for the treatment of animals.

[3][5] Against these ideas, Aristotle (384–322 BCE) argued that non-human animals had no interests of their own, ranking far below humans in the Great Chain of Being, or scala naturae, because of their alleged irrationality.

[9] Theophrastus did not prevail, and it was Aristotle's position—that human and non-human animals exist in different moral realms because one is rational and the other not—that persisted largely unchallenged in the West for nearly two thousand years.

[10] The Jewish oral tradition developed the principle of Tza'ar ba'alei chayim, forbidding inflicting unnecessary pain on animals.

[11] Philosopher Peter Singer writes that animals, along with criminals and other undesirables, largely fell outside the Roman moral sphere.

Under Trajan [53–117] ... lions, tigers, elephants, rhinoceroses, hippopotami, giraffes, bulls, stags, even crocodiles and serpents were employed to give novelty to the spectacle ...

[15] Plutarch, who was Greek but lived in Rome, argued strongly against meat eating, seeing it as responsible for much of the cruelty in the world: For the sake of some little mouthful of flesh, we deprive a soul of the sun and light ... And then we fancy that the voices it utters and screams forth to us are nothing else but certain inarticulate sounds and noises, and not the ... entreaties ... of each of them ...[16]Legal philosopher John Finnis writes that the Romans invented the concept of "ius", meaning what is right, just, or lawful, and it is from this concept that the idea of a "right" as a claim, an entitlement, an immunity, or a liberty, arose in the late-medieval to modern period.

The idea is that any wrong not only "deforms the agent", as Finnis writes of human beings, but also offends the victim's "fundamental equality".