In her book Defending Beef, Nicolette Hahn Niman absolves the act of eating meat from moral inquiry on the grounds that humans have always eaten animals. She explains that a “food web” in which animals and plants routinely consume each other (yes, plants eat animals) places all life in “an endless cycle of regeneration.” As a result, she concludes: “something so fundamental to the functioning of nature cannot be regarded as morally problematic.” Please re-read that quote to make sure it sinks in.
This logic is sloppy, commonplace, and dangerous. Critics of vegetarianism or veganism routinely chant the mantra that humans “were meant to eat animals.” This comment has a “no further questions asked” tone to it. It seems intuitively true and, unfortunately, for consumers otherwise inclined to question the moral implications of eating animals, it serves as a convenient escape hatch from a question many meat eaters are eager to avoid: is it wrong to slaughter a sentient animal for food when it’s unnecessary to do so?
By relying on the “humans were meant to eat meat” logic, Niman fails to examine the assumption upon which it rests. At its foundation, the claim implies that any adaptive quality that humans might have evolved to survive is, to quote Niman, “so fundamental to the functioning of nature” that it “cannot be regarded as morally problematic.”
The problem here is that evolutionary adaptation—the essence of the “functioning of nature”—includes untold morally disgusting behaviors that, while perfectly natural in the same way that eating animals is considered natural, are rightly deemed abhorrent by decent people living in a civil society.
Take infanticide. The adaptive advantage of infanticide for many vertebrates is well-supported. This is true for humans as well as primates. Among the !Kung hunter gatherers of Kalahari, about one in a hundred births end in infanticide. In regions of New Guinea, according to anthropologist Sarah Hrdy, infanticide is “off the charts,” as mothers who wanted sons (or whose partners wanted sons) will often kill their daughters.
Rather than accept this behavior as beyond moral scrutiny due to its proven “natural” or adaptive quality, civil society rightly rejects infanticide as a totally barbaric practice. The human corrective, according to many evolutionary biologists, has been monogamy—a civilized arrangement often deemed “unnatural,” but certainly morally superior to the alternative.
Another (admittedly more controversial) example to consider is rape. In 2000, Randy Thornhill and Craig T. Palmer argued in A Natural History of Rape that the urge to rape is the legacy of an evolutionary adaptive trait (or the by-product of an adaptive trait, such as aggression in men). Their theory (not surprisingly) encountered a firestorm of objection, much of it concerned that evolutionary psychology was being used as “excuse” for inexcusably horrific behavior.
Whether or not Thornhill and Palmer are right (their hypothesis is still debated), the regrettable fact remains that rape has existed throughout recorded human history, across human cultures, as well as throughout the non-human animal world. Evolutionary psychology, moreover, remains a powerful heuristic tool with which to understand the once (potentially) adaptive, if repulsive, mechanism underscoring rape.
As recently as 2013, a major peer-reviewed study has argued that, “forced sex is the outcome of an innate conditional strategy which enables men to circumvent parental and female choice when they experience a competitive disadvantage, or when the costs of doing so are low.” Other scholars are seeking to reconcile a feminist and an evolutionary psychological understanding of rape, negating the “men can’t help it” suggestion while preserving the evolutionary perspective that Thornhill and Palmer promote.
To clarify any misunderstanding on this point, the takeaway is not to equate the immorality of rape with the immorality of eating animals. Instead, it is to note that both behvaiors (one, of course, being far more common than the other) may have served adaptive functions that qualify them as “natural” and, according to Niman’s logic, beyond moral assessment.
Finally, take something much more common and less controversial: lying. From the perspective of natural adaptation, lying has likely been even more essential to human evolution than eating animals (for, as we know, some societies subsisted on plants, but lying has no plant-based counterpart!).
In Why We Lie: The Evolutionary Roots of Deception and the Unconscious Mind, David Livingstone Smith situates lying in our evolutionary past, one in which strategic deception had clear adaptive benefits. Lying is thus perfectly natural in the same way eating animals is perfectly natural–it’s an act humans have always done to foster evolutionary adaption. But that hardly makes it morally inert in contemporary life. We don’t like it when people lie.
Which brings me back to Niman. Today, of course, we consider all of these behaviors, in varying degrees, to be morally significant. Nobody in her right mind would contemplate infanticide, lying, or rape and declare, as Niman does of killing animals, that, “something so fundamental to the functioning of nature cannot be regarded as morally problematic.” To the contrary, she would condemn these acts as wrong. It is on the basis of such condemnation that human civil society exists and, on good days, thrives.
Why killing animals for food we do not need gets an “it’s natural” pass is a question that Niman has yet to answer. Until she does, I see no reason to accept the naturalistic fallacy at the core of her justification for eating animals.