A few days ago, on a social media forum, I was having an interesting discussion with someone who rejected the notion that there are universal moral rules. I get it, until a few years ago I was just as skeptical, and thought that morality is obviously a cultural invention, and as such varies from place to place and from time to time.
That there is such variation is an empirical fact: what goes in Athens doesn't go in Corinth, what was ethical two thousand years ago (or even 50, in certain respects) is not ethical today. But that isn't the question: the issue is not whether there is variation in the actual ethics deployed by different people at different times. The question is whether there should be such variation. In other words, the issue is prescriptive, not descriptive.
I know, I know, am I not aware of the horrible things that people have done to other cultures in name of their allegedly superior and "universal" morality? Yes, I am. But, again, that's irrelevant to the question at hand. Just because some people use notion X as an excuse to pursue their own personal interest it doesn't mean that notion X is invalid. It just may mean that such people are hypocrites, or ignorant, or both.
The issue is made more complicated by the fact that some "ethical" rules obviously are arbitrary, and entirely culturally dependent. Consider, for instance, prohibitions concerning particular foods. Unless you happen to be allergic or have some other health-related reason not to eat something -- and setting aside truly ethical questions concerning environmental impact, animal suffering, and labor conditions -- it simply has no moral import whether you do or do not eat, say, zucchine.
By contrast, do we really want to say that young girls' genital mutilation, murder, slavery, or genocide, are not always unethical, regardless of who does it and why? Then again, there are actions whose moral valence depends on the circumstances: is stealing, or even killing (there is a difference between killing and murdering), always unethical? Not if one steals from someone much better off than himself in order for his family to survive, or kills in self defense. And so forth.
When I say that some ethical rules are universal, I mean for humankind, not "universal" in the way Kant famously understood the term: I don't think that there are moral laws that are on par with the law of gravity. But I do think that some ethical rules are pretty much universally applicable to human societies, regardless of time and place.
The reason is because human beings are a particular type of highly social animals capable of reason and language. Given our (evolved) socio-biology, certain things are acceptable (or not) across the board. Although, had we evolved differently (for instance, as a solitary species), things would accordingly be different, and even the very concept of morality may not make sense. Another way to put what I'm trying to say is that human ethics is not arbitrary or relativistic, but rather constrained by objective facts about human nature. (Yes, I believe in such a thing as human nature.)
Do I have any examples of allegedly universal moral rules? Glad you asked. Anthropologists have actually identified seven distinct moral rules that appear to be universal across human societies. But I'd like to focus on one in particular here: the golden rule. It's actually two rules, depending on how it is phrased: the positive version says that we should treat others as we would ourselves want to be treated. The "negative" version, sometimes referred to as the silver rule, says that we should not do to others what we wouldn't want them to do to us.
One version or another of the golden/silver rule is found in pretty much every human society, regardless of place or time. Here is a sampler:
"That which you hate to be done to you, do not do to another." (Egyptian papyrus, Late Period, 664-323 BCE)
"Avoid doing what you would blame others for doing." (Thales of Miletus, 624-546 BCE)
"Hurt not others in ways that you yourself would find hurtful." (Buddha, Udanavarga 5:18, 623-543 BCE)
"What you do not wish for yourself, do not do to others." (Confucius, Analects XV.24, circa 500 BCE)
"Regard your neighbor's gain as your own gain, and your neighbor's loss as your own loss." (Daoism, T'ai Shang Kan Ying P'ien, 4th century BCE)
"One should never do something to others that one would regard as an injury to one's own self. In brief, this is dharma. Anything else is succumbing to desire." (Hinduism, Mahābhārata 13.114.8, 400 BCE-400 CE)
"Whatever is disagreeable to yourself do not do unto others." (Zoroastrian Shayast-na-Shayast 13:29, 300 BCE-1,000 CE)
“What is hateful to you, do not do to your fellow: this is the whole Torah; the rest is the explanation; go and learn." (Hillel the Elder, Shabbath folio:31a, Babylonian Talmud, 110 BCE-10 CE)
"This is the kernel of my advice: treat your inferiors as you would be treated by your betters." (Seneca the Younger, Letters to Lucilius, XLVII.11, 4 BCE-65 CE)
"Do to others what you want them to do to you." (Matthew 7.12, circa 50 CE)
"None of you [truly] believes until he wishes for his brother what he wishes for himself." (Muhammad, An-Nawawi's Forty Hadith 13, 570-632 CE)
I could go on, but I think you get the idea. The golden/silver rule has, of course, been criticized -- though whether a given ethical principle is defective in some ways is yet again an entirely different question from whether it is universal.
The funniest criticism I am aware of is by George Bernard Shaw, who famously said: "Do not do unto others as you would that they should do unto you. Their tastes may not be the same." However, in The Concept of Morals (1937), British educator and public philosopher Walter Terence Stace claims that Shaw was too clever by one half, and missed the point of the rule: "Mr. Bernard Shaw's remark is no doubt a smart saying. But it seems to overlook the fact that 'doing as you would be done by' includes taking into account your neighbor's tastes as you would that he should take yours into account. Thus the 'golden rule' might still express the essence of a universal morality even if no two men in the world had any needs or tastes in common."
Indeed, one often hears obviously superficial rejections of the golden/silver rule that sound like they have been inspired by the same thought process that affected Shaw. Even Kant fell for it, which is particularly ironic given that his famous categorical imperative shares much with the golden/silver rule. Kant said, for instance, that a duly convicted prisoner could appeal to the judge in order not to be sent to prison on the grounds that, after all, the judge himself wouldn't want to be sent to prison.
But American philosopher Marcus George Singer observed in this respect that there are two very different ways of looking at the golden/silver rule: (1) as requiring that one performs specific actions that one would be okay if others did it to her; or (2) as requiring that one guides one's behavior in the same general ways that one wants others to. The standard counter-examples to the golden/silver rule have some force against the first understanding, but not the second.
What about the difference between the positive (golden) and negative (silver) versions of the rule? It reflects a broader difference between positive and negative duties. At the very least, we have the negative duty -- as expressed by the silver rule -- not to harm other people. But it would be nice if we went so far as embracing the positive duty -- as expressed by the golden rule -- to actually be helpful to others.
Why might the golden/silver rule have achieved the universal status in human societies that I have documented above? Possibly because it articulates a much more widespread principle in evolutionary biology known as reciprocal altruism, the notion -- evolved by natural selection in a large number of social species -- that cooperation and reciprocation (I scratch your back, you scratch mine) should be the default behavior in a group, because everyone benefits. Reciprocal altruism is a so-called evolutionarily stable strategy, meaning once it appears in a population it is reinforced by natural selection and it is difficult to dislodge.
It could be objected that this isn't really "altruism," because one does things conditionally (IF you scratch my back THEN I scratch yours). But British philosopher Philippa Foot, one of the people who has been most instrumental in the modern resurgence of virtue ethics, has argued -- convincingly, in my opinion -- that morality always is a system of conditional (not absolute, pace Kant) imperatives. After all, the very word morality comes from the Latin moralis, which is how Cicero translated the originally Greek term, êthos. They both refer to people's character and the sort of behaviors that it is sensible to engage in if we want to live and thrive in a social group. There is nothing more, or less, than that to ethics.