According to the major monotheistic religions—Judaism, Christianity, and Islam—humans have a special nature and destiny, different from and superior to those of other animals. Created by a divine power, humans resemble it in not belonging entirely to the natural world. They exercise a freedom of will no other animal possesses and, thanks to the afterlife, are exempt from mortality.

In Western societies monotheistic ideas no longer prevail in the explicit forms they once did, but the claim that humans have a unique standing has not been renounced. It continues to shape our view of ourselves and our planet, though the defining feature of humanity is now commonly identified as rationality or self-awareness rather than the possession of a soul. As Melanie Challenger writes in How to Be Animal:

For those with deep belief in a creator, we have a soul that is unique to the human body. For secular humanist thinkers, we have soul-like mental powers that are unique to the human brain. Each is a reason for why humans aren’t truly animals. At least, not in any crucial way.

We know from evolutionary biology that humans emerged from the natural world. At the same time, many think we have cast off our animal origins; some think we can direct our future evolution. This discrepancy between what we know from scientific inquiry and the image we have formed of ourselves is Challenger’s central theme: “The truth is that being human is being animal. This is a difficult thing to admit if we are raised on a belief in our distinction.”

Challenger, a British writer on environmental issues, notes that this belief is not confined to monotheistic religions. In Hindu and Buddhist traditions, humans are at times represented as having greater spiritual worth than other animals: “In the Taittiriya Upanishad the god Shiva makes clear that humans are unique in their ability to act on knowledge.” In some currents of Buddhism, humans alone have the potential for deliverance from the cycle of birth, death, and rebirth.