In his 1977 book, The Dragons of Eden, noted philosopher Carl Sagan asked: "How smart does a chimpanzee have to be before killing him constitutes murder?" Indeed, chimps do share 99 percent of their active DNA with humans, and are closer genetically to us than they are to gorillas.
Sagan went on to ask: "If chimpanzees have consciousness, do they not have what until now has been described as "human rights"?" Well, they should, but we humans like to have it both ways. We morally justify experimentation on animals, for example, by saying they are not like us, not within our "community of equals." But then we justify the research scientifically by saying they are like us. They would have to be, of course, for us to obtain useful information applicable to humans.
I chuckle when I hear animal advocates called "anti-science" because of their opposition to animal experimentation and other uses of animals that cause pain or distress, only to then hear all kinds of very unscientific justifications—such as that animals don’t feel pain as we do—for visiting some of the most horrendous treatment on conscious, sentient beings.
It even gets religious: After all the other rationalizations have been exhausted, and all the jokes have been mined over whether or not broccoli should also have rights, it turns to God, who supposedly sanctions the physical and psychological abuse of animals because he (sic) put them here for our use; gave us dominion; made us in his image, not theirs; and gave us, not them, souls. Science? Hardly, since not any of that can be proven in any way whatsoever.
Regardless, evidence of intelligence, especially human-like reasoning and cognitive ability, seems to be the most compelling reason for people to go along with the idea of rights for animals. Apes have the added benefit that they look like us, too, which is probably why the Great Ape Project and others have gotten as far as they have in persuading society to re-think our relationship with them.
Intelligence shouldn’t be the only consideration (200 years ago, British economist Jeremy Bentham argued: "The question is not, "Can they reason?" nor, "Can they talk?" but rather, "Can they suffer?""). But to the extent that it is, in this context intelligence means power. And at the end of the day, we treat animals—smart or dumb, hominid or cetacean, wild or domestic—as poorly as we do because we can get away with it.
But just because one has power doesn’t mean one must choose to use it. Given the growing body of knowledge about animal intelligence, culture and social systems, the right choice here is to not use power selfishly simply because we can. Despite similar power relationships throughout history (based not on intelligence but on economics), decent white people supported civil rights and reasonable men supported women’s rights. Similarly, people of conscience should support animal rights and, by extension, the rights of nature to not simply exist for our enjoyment and exploitation. That’s the kind of world I want to live in.