Nobody who grew up watching Flipper reruns has any doubt about the intelligence of dolphins, but Andy Revkin at Dot Earth looks at it, and the issue of animal intelligence a lot more seriously. He discusses the issue with Thomas I. White, a professor of business ethics. The key point:
The scientific evidence is so strong for the intellectual and emotional sophistication of dolphins that there simply is no question that they are ‘nonhuman persons’ who deserve respect as individuals. Anyone who doubts this either is unfamiliar with the data or doesn’t understand the ethical significance of it. Both the killing and captivity of dolphins are ethically indefensible.
The issue extends beyond dolphins. Revkin quotes the mission statement of the Institute for Ethics and Emerging Technologies:
Owing to advances in several fields, including the neurosciences, it is becoming increasingly obvious that the human species no longer can ignore the rights of non-human persons. A number of non-human animals, including the great apes, cetaceans (i.e. dolphins and whales), elephants, and parrots, exhibit characteristics and tendencies consistent with that of a person’s traits like self-awareness, intentionality, creativity, symbolic communication, and many others. It is a moral and legal imperative that we now extend the protection of ‘human rights’ from our species to all beings with those characteristics.
Then of course the question is: why stop there? Pigs are pretty smart. Revkin quotes Carl Safina on that one:
The argument against it really becomes convenience. Their capture, enslavement, and slaughter is something we do because we want to, because our devices make it possible, and because they can’t adequately fight back.
We promote vegetarianism on TreeHugger because of the carbon footprint of meat; that's why we can justify the concept of the weekday vegetarian. But reading Revkin makes me wonder whether that is really good enough anymore.