The following is an excerpt from the book, Meat Logic: Why We Eat Animals by author Charles Horn. The book takes an in depth look at the many rationalizations people use for eating animal products. One very popular class of rationalizations assumes that evolution dictates our consumption of animal products, making it morally neutral. Horn deals with each of the many evolution and nature variations separately and in detail, but has the following to say as a final word on the topic
“… there are numerous variations on the argument that evolution has placed us in the role of eating animals and therefore eating animals belongs outside of morality. While a very small fraction of people actively concern themselves with the treatment of animals while alive and make it a point to only buy so-called “humane” meat or only hunt animals in the wild, the act of eating animals itself is taken for granted as a simple fact of nature and therefore outside of morality.
When it comes down to it, though, one of two statements is being made. Either the person is simply saying that we eat animals as a statement of natural fact which does not require any further discussion, or the person is saying that eating animals is necessary for our health.
In the case of simply stating that we are omnivores (ignoring the fact that we are not obligate omnivores), what we are in effect saying is that we should derive our morals from evolution’s survival of the fittest. This is faulty reasoning because survival of the fittest is easily shown to be a horrible moral system where theft, rape, and murder are okay as well. We do not apply the morality of survival of the fittest to domination, theft, rape, murder, or how we should treat the sick or weak or less fortunate or less intelligent among us, and similarly we should not apply it to eating animals.
In the case of stating that we need to eat animals for our health (ignoring the scientific research and the fact that millions of vegans are living long healthy lives at this very moment), what we are in effect saying is that evolution has put a gun to our heads that forces us to eat animals. This is faulty reasoning because even if it were true, eating animals would still remain within morality. If the gun is to our head to eat animals, is the gun to our head to eat more than we need to be healthy? Is the gun to our head to eat not only fish (or better yet, bivalves), but also birds and mammals? Is the gun to our head to torture the animal? Is the gun to our head to use animals for other non-food purposes as well? And if the gun were ever removed from our head through vitamins and fortified foods, should we still go about our business as if the gun were still to our head?
Clearly the omnivore/evolution way of thinking is deeply ingrained, but nature/evolution is a morally faulty way of thinking altogether as it can justify pretty much whatever horrible things we want. The following paragraph may appear at first glance to be offensive, but be clear that we are only pointing out the similarities in thought process of the person providing their rationalization. See how many rationalizations from the previous chapters you can spot.
“Men were designed by millions of years of evolution to be sexual opportunists. As a guy, sexual desire is unquestionably deep inside my DNA. It’s what makes me a man. Is it possible for a man to survive without sex or through masturbation alone? Sure, maybe that’s true for some men, for a while. But a man can’t thrive without sex. I get depressed when I haven’t had real sex for a while. I don’t feel my complete self. I don’t feel 100% a man. So when I’m not getting it willingly, I listen to my body and do what my body is asking for, what it was designed for. I have nonconsensual sex. And don’t tell me that I don’t love women. I think it’s terrible how some men treat women. I don’t condone any of that. I only have humane nonconsensual sex. I buy my women the best food, the best drinks, we go dancing – you should see how happy they are. And when it’s time I slip them a drug and they don’t feel a thing and they’re unconscious in an instant. There’s no fear and they never even know it’s coming. And I always appreciate their sacrifice. Before I start I always say a blessing and express my gratitude for the sexual sustenance gift that they are providing me. Listen, if you don’t want to have nonconsensual sex that’s your personal choice and I respect it, but please respect my right to have nonconsensual sex. Men are sexual opportunists. Period. It’s simple biology. Evolution. Nature. You think the lion feels bad when he’s having nonconsensual sex with the lioness?”
The reason we used sex as our example is that sex is viewed as a baser drive closer to eating, but versions of the example above could have been provided to justify theft or slavery or even murder. If we accept evolution’s survival of the fittest as our starting point then that is ultimately the morals we are promoting.
Any appeal to nature and evolution is thus ultimately faulty because morally it is just not the right way of thinking on the matter. Regardless of nature and our own barbaric history, civilization is meant to take us out of the realm of “survival of the fittest” and “might makes right” mentalities and to evolve beyond them. Morally speaking, it is time to evolve beyond thinking that our base evolutionary desire gives us the right to exploit, enslave, torture, or kill others. It does not. It is a prejudice.”