For much of history, philosophers and religious thinkers have believed there are absolute differences between humans and all other living things. Usually, only humans have been thought capable and deserving of moral standing (either as moral agents, who are capable of acting morally, or as moral patients, who are owed moral duties).

But this view is now forcefully challenged, with many disputes or debates about the tenets that underlie in. Animal advocates argue that many animals do have some of these traits, or that the traits they dont have are irrelevant for determining moral standing.

Recent discoveries also indicate that humans have much in common with at least some of the animals. This has led to much rethinking, and to a powerful critique of our relationships with other living creatures.