If human is defined by our ability to cook and to eat meat, are raw vegan still human?

Feb 19th 2009 | CHICAGO
From The Economist print edition

The evolutionary role of cookery

Mary Evans

YOU are what you eat, or so the saying goes. But Richard Wrangham, of Harvard University, believes that this is true in a more profound sense than the one implied by the old proverb. It is not just you who are what you eat, but the entire human species. And with Homo sapiens, what makes the species unique in Dr Wrangham’s opinion is that its food is so often cooked.

Cooking is a human universal. No society is without it. No one other than a few faddists tries to survive on raw food alone. And the consumption of a cooked meal in the evening, usually in the company of family and friends, is normal in every known society. Moreover, without cooking, the human brain (which consumes 20-25% of the body’s energy) could not keep running. Dr Wrangham thus believes that cooking and humanity are coeval.

In fact, as he outlined to the American Association for the Advancement of Science (AAAS), in Chicago, he thinks that cooking and other forms of preparing food are humanity’s “killer app”: the evolutionary change that underpins all of the other—and subsequent—changes that have made people such unusual animals.

Humans became human, as it were, with the emergence 1.8m years ago of a species called Homo erectus. This had a skeleton much like modern man’s—a big, brain-filled skull and a narrow pelvis and rib cage, which imply a small abdomen and thus a small gut. Hitherto, the explanation for this shift from the smaller skulls and wider pelvises of man’s apelike ancestors has been a shift from a vegetable-based diet to a meat-based one. Meat has more calories than plant matter, the theory went. A smaller gut could therefore support a larger brain.

Dr Wrangham disagrees. When you do the sums, he argues, raw meat is still insufficient to bridge the gap. He points out that even modern “raw foodists”, members of a town-dwelling, back-to-nature social movement, struggle to maintain their weight—and they have access to animals and plants that have been bred for the table. Pre-agricultural man confined to raw food would have starved.

Firelight

Start cooking, however, and things change radically. Cooking alters food in three important ways. It breaks starch molecules into more digestible fragments. It “denatures” protein molecules, so that their amino-acid chains unfold and digestive enzymes can attack them more easily. And heat physically softens food. That makes it easier to digest, so even though the stuff is no more calorific, the body uses fewer calories dealing with it.

In support of his thesis, Dr Wrangham, who is an anthropologist, has ransacked other fields and come up with an impressive array of material. Cooking increases the share of food digested in the stomach and small intestine, where it can be absorbed, from 50% to 95% according to work done on people fitted for medical reasons with collection bags at the ends of their small intestines. Previous studies had suggested raw food was digested equally well as cooked food because they looked at faeces as being the end product. These, however, have been exposed to the digestive mercies of bacteria in the large intestine, and any residual goodies have been removed from them that way.

Another telling experiment, conducted on rats, did not rely on cooking. Rather the experimenters ground up food pellets and then recompacted them to make them softer. Rats fed on the softer pellets weighed 30% more after 26 weeks than those fed the same weight of standard pellets. The difference was because of the lower cost of digestion. Indeed, Dr Wrangham suspects the main cause of the modern epidemic of obesity is not overeating (which the evidence suggests—in America, at least—is a myth) but the rise of processed foods. These are softer, because that is what people prefer. Indeed, the nerves from the taste buds meet in a part of the brain called the amygdala with nerves that convey information on the softness of food. It is only after these two qualities have been compared that the brain assesses how pleasant a mouthful actually is.

The archaeological evidence for ancient cookery is equivocal. Digs show that both modern humans and Neanderthals controlled fire in a way that almost certainly means they could cook, and did so at least 200,000 years ago. Since the last common ancestor of the two species lived more than 400,000 years ago (see following story) fire-control is probably at least as old as that, for they lived in different parts of the world, and so could not have copied each other.

Older alleged sites of human fires are more susceptible to other interpretations, but they do exist, including ones that go back to the beginning of Homo erectus. And traces of fire are easily wiped out, so the lack of direct evidence for them is no surprise. Instead, Dr Wrangham is relying on a compelling chain of logic. And in doing so he may have cast light not only on what made humanity, but on one of the threats it faces today.

Regan begins with claiming all individuals who are the experiencing subjects of a life have inherent values. The inherent value is independent of the usefulness of the individual. Unlike the utilitarianism, this view in principle denies that we can justify good results by using evil means that violate individual rights. Treating others in ways that fail to show respect for the other’s independent value is to act immorally, to violate the individual’s right (p.393). Since we accept the fact that human who lack of intelligence, autonomy or reason has inherent value. To be rational, we have to also accept the view that animals like them has no less inherent value. All who has inherent value have it equally, whether they are human or animal (p.394). Therefore we have to recognize the equal inherent value of animals and their equal right to be treated with respect.

I agree with Regan both human and animal have the same inherit rights. However he is too hastily to equate these inherent rights with human rights. We must first examine what is the content of the inherent rights exactly, only then we can determine how human should treat animals morally.

According to the rules of nature, animals high up in the food chain have the rights to prey on animals low in the food chain. It would be absurd to condemn lions killing gazelles for food being immoral. It would be even more absurd to persecute the lions for committing murders. It would be equally absurd to prevent the lions from killing the gazelles or any other animals, doing so would definitely drive the lions into extinction. It is quite obvious that it is moral for the animals to kill other animals for their own good. Following the same rules of nature, it is moral for animal to honor special relationship within their own species, such as wolf packs. So it must be moral for human to take the welfare of other Homo sapiens more important than members of other species. Since human and animal share the same inherent rights, it is only moral to allow human kill animals as resources and allow human being speciesism.

In response to my objection, Regan may argue that I have confused positive rights with negative rights. My objection is based on human and lions have the same positive rights of killing other animals, but he is suggesting animals have negative rights in the form of a moral protection from harms, since every subject of life have the same inherent negative rights. The lions do not have moral capacity to fulfill their moral duty, so we cannot apply moral judgment on whether it is wrong for the lions to kill the gazelles. On the other hand, human possess rationality or moral autonomy, so it is wrong for human to violate our moral duty by harming the animals.

Regan’s response did not answer my objection at all. I was asking where the inherent rights come from and suggest a reasonable way to determine its scope. Regan merely repeat his conclusion without showing us how to derive the inherent rights equal to moral protection from harm. If human have inherent rights of being speciesism, then human has no moral obligation for not harming the animals. The human rights of infants and retarded can be justified by the inherent right of human speciesism, then the inherent rights of all experiencing subjects do not include protection from harm in all circumstances. Why can’t the inherent rights only give animals some protection that is less than what Regan has claimed? How about animals have inherent rights to survive as a species, so human can kill individual animal but we should not drive them into extinction? How about animal have inherent rights for not being harmed by human if there is no conflict of interest, so we can build animal factories to provide food supplies for us, but we cannot kill birds in the city unless they become environmental hazards? Regan gives no reason why we should draw the line of the inherent rights that animals enjoy the same as human rights.

In conclusion, Regan’s argument for the animal rights is invalid. Giving that all living beings share the same inherent rights, we cannot logically deduce this inherent rights equals to human rights that we are familiar with.