GARY FRANCIONE & ANNA CHARLTON: ‘Society extends the right not to be property to all people irrespective of their intelligence, beauty, strength or any other characteristic. It doesn’t matter whether a person is a genius or has a learning disability. No-one should be the property of someone else. Slavery still exists, but no one defends it.
The same reasoning holds for nonhuman animals. If animals are to matter morally, and not be just things, they cannot be treated as property, since if they are property they have no intrinsic moral value. Their only value is that accorded to them by their owners. The only reason we deny this right to nonhumans is that they are not human. But that is no different from using any other morally irrelevant characteristic such as race or sex to justify slavery or otherwise fail to accord equal consideration to others.
The only characteristic that animals must have in order to matter morally is sentience. It is not necessary that they have humanlike minds. If they are sentient, they have interests, including the interest in continuing to live and in not suffering pain or distress. That is all that is necessary.
If we agree that animals matter morally, we are committed to recognizing that all sentient nonhumans have a moral right not to be used as property. This requires that we stop using animals as resources. In other words, we must be morally committed to stop eating, wearing, or otherwise using animals’. SOURCE…