The Golden Rule’s power points to a universal moral principle

Philosophical perspectives on the Golden Rule typically focus on the Golden Rule’s well-known flaws and may even have a dismissive tone.

The philosopher Dan Flores recently wrote:

“If ethics is the inquiry into the basic claims of morality, then upon philosophical scrutinization of the Golden Rule, we find that, in the words of Quine, ‘there is nothing to scrute’ after all. We should focus our attention on ordinary moral principles instead.”

As an admirer of the Golden Rule, I took offense on its behalf. In response, I will both defend its permanent cultural usefulness and argue that it points us to a universal moral principle.

Rather than there being “nothing to scrute”, the Golden Rule, particularly in the form “Do to others as you would have them do to you”, may be the most culturally useful heuristic (a usually reliable, but fallible, rule of thumb) for moral behavior in existence. We will see there are good reasons that Jesus is quoted in Mathew 7:12 as saying the Golden Rule summarizes morality and even present-day secular people commonly quote it as their primary moral guide. Despite the Golden Rule’s flaws, it has remained a popular and useful moral principle since ancient times and in cultures around the world.

Building on insights into the origin and function of morality by the Greek philosopher Protagoras and Charles Darwin, I’ll argue we can understand why the Golden Rule’s specific flaws exist. Understanding when the Golden rule will advocate immoral behavior is a useful result on its own. In addition, this knowledge plus a bit about cooperation strategies leads to a perhaps even more surprising result. We can identify the cross-species universal moral principle that the Golden Rule is a heuristic for. These are the potential payoffs for scrutinizing the Golden Rule.

In one of Plato’s dialogs, the philosopher Protagoras explained to Socrates that morality’s function, the primary reason it exists, is it increases the benefits of cooperation. (Protagoras illustrated his argument with the Greek myth that Zeus gave all people a moral sense to enable them to cooperate in groups. The existence of this myth implies that “morality as cooperation” was a common understanding of morality among people in Protagoras’ time and likely well-known to Socrates.)

If the function of morality is to increase the benefits of cooperation, then how might we describe immoral behavior except as acting to decrease the benefits of cooperation? Then when might the Golden Rule’s guidance be expected to decrease the overall benefits of cooperation? Such circumstances include the Golden Rule’s commonly recognized “failures” when 1) a judge does not punish a criminal because the judge would like to not be punished in the same circumstances, 2) a soldier acts generously toward an enemy soldier in time of war resulting in the enemy soldier killing the generous one, and 3) people’s “tastes differ”, as Bernard Shaw pointed out,  regarding how they want to be treated. Protagoras’ 2500-year-old perspective on morality as cooperation reveals the “why” of the Golden Rule’s standard failure examples. Those failures occur when following the Golden Rule would likely decrease the benefits of cooperation and thus be immoral.

If the function of moral behavior actually is increasing the benefits of cooperation, then we have an explanation for the flaw that produces the Golden Rule’s failures. But given this flaw, how has the Golden Rule remained such a useful moral norm?

“Do to others as you would have them to do to you” advocates initiating cooperation based on the generally reliable assumption that both parties like to be treated similarly.  For example, following the Golden Rule would advocate sharing food, coming to other’s aid when they need help, and treating other people fairly, even when one has the power to treat them unfairly. Such cooperation was critical for survival in pre-civilization societies and the material and psychological benefits of cooperation remain, even now, the overwhelming reason we form and maintain societies and moral codes.

However, the Golden Rule does not advocate mere reciprocity – I help you and you help me. There is no hint in the Golden Rule that people helped will directly reciprocate. If the people helped also follow the Golden Rule, then they will help whoever in the group needs help. Radically more benefits of cooperation are made possible when “all help all” in a large group rather than when help is dependent on pairs of reciprocators (pairs of cooperating people).

The sophisticated form of cooperation initiated by the Golden Rule is called indirect reciprocity. It is perhaps the most powerful cooperation strategy known. The Golden Rule has remained a central moral principle since ancient times because the behaviors it advocates can so effectively increase the benefits of cooperation. (Note that the Golden Rule only initiates indirect reciprocity. Maintaining indirect reciprocity requires exploiters and freeloaders be punished, perhaps just by ceasing to cooperate with them. Our evolved moral sense is generally eager to punish ‘immorality’. We can think of indirect reciprocity as being initiated by the Golden Rule. But indirect reciprocity must be maintained by freeloaders and exploiters being “punished” as motivated by our moral sense’s indignation about other people’s immorality, our own guilt and shame at our own immorality, and by cultural punishment norms for  immoral behavior.)

But was Protagoras right? Is the function of morality merely to increase cooperation? If this is true, then Protagoras’ hypothesis faces a daunting task. It must explain, as elements of cooperation strategies, virtually everything we know about our moral sense and cultural moral codes.

After Protagoras, Charles Darwin in The Descent of Man (1871) proposed the next important insight into morality as cooperation. He speculated that biological evolution selects for altruism toward others (“altruism” here referring to helping without expectation of direct reciprocity) and moral behavior in general, because more cooperative groups can outcompete less cooperative groups. Darwin was right. By pointing out that evolution selects for increased cooperation within groups which are sometimes in deadly competition with other groups, Darwin explained two puzzling phenomena: altruism and, perhaps unknowingly, why moral norms in different cultures can be so diverse, contradictory, and even bizarre.

If groups are in competition, it can be a matter of life and death to know who is committed to your group and who might be in a competing group. This can be a problem in large groups such as tribes where individuals may not know everyone well. Markers of membership in and commitment to a cooperative group, such as hair and dress style (which are immediately obvious), circumcision, food and sex taboos, and allegiance to one god versus another (which are more hidden, but still important for distinguishing “us” from “others”) were readily adopted and enforced as “moral norms” because they were effective at increasing the benefits of cooperation within groups.

The diversity, contradictions, and bizarreness of cultural moral norms can be understood as due to two primary causes. First, as described above, groups will use different “markers” of membership and commitment to the group to clearly distinguish themselves from competing groups. Second, societies will use different definitions of who deserves full moral regard (perhaps only men or only one tribe) and who is worthy of less or even no moral regard (perhaps women, slaves, or an enemy group).

Thus, Darwin’s idea that morality is selected for because it enables groups to outcompete other groups largely explains why past and present moral codes can superficially appear to be such a chaotic mess. Indeed, Darwin’s evolutionary explanation, plus a little modern knowledge about cooperation strategies, explains virtually everything we know about our moral sense and past and present cultural moral codes as described here and here.

But a well-functioning moral system must include answers to questions such as “Who will be in favored in-groups? Just family, friends, countrymen, or everyone?” and “What interactions between groups are moral?”. Can an evolutionary perspective illuminate these questions?

There has been a lot of progress in the science of cooperation and moral behavior in recent decades. That science supports a claim about what is universally moral which may help answer these questions. This principle is “Increasing the benefits of cooperation without exploiting others is universally moral”.

The word “moral” here is used in the normal cultural and scientific sense to refer to right and wrong behavior, meaning judged worthy of praise or condemnation by our moral sense and cultural moral codes. “Universally moral” refers to what is universal about all the diverse, contradictory, and bizarre behaviors our moral sense and cultural moral codes motivate and advocate.  The claim is ‘true’ in a scientific sense because “cooperation without exploiting others” is a necessary (universal) subcomponent of all cooperation strategies (moral behaviors) relevant to human morality. For example, even cooperating in an in-group to exterminate out-groups relies on people following the above principle and thus maintaining this cooperation by not exploiting others in their in-group.

I know of no philosophical argument that this moral principle is what we somehow imperatively ‘ought’ to do regardless of our goals. But no such argument is generally accepted for any moral principle. Since none have been shown to exist, traditional philosophical “imperative oughts” cannot be the basis of a society’s rational choice for moral references for refining their moral codes. But moral references can be rationally chosen based on whichever moral principle is believed to be most likely to aid in meeting shared needs and preferences.

The cultural usefulness of this universal moral principle is due to its ability to directly and powerfully help us achieve shared goals, its innate harmony with our evolved moral sense, and our intellectual recognition of its mind independent, uniquely “universally moral” status.

This essay is part of an exploration of different approaches to explaining this evolutionary perspective on morality. The approach I personally prefer begins with first principles about cooperation that are innate to our physical reality and independent of human existence. But tastes differ.

If adopting and practicing this principle can be rationally justified simply by a society’s desire to best meet their shared needs and preferences, would that leave moral philosophers out of a job? No, of course not.

First, moral philosophy’s tools and insights would be needed to build, on the bare foundation science provides, coherent, well-functioning moral systems. Such systems must address issues such as abortion, human rights, and relative moral obligations to family, friends, people you will never meet (including future generations), animals, and eco-systems. Second, philosophical answers to larger ethical questions such as “What is good?”, “How should I live?”, “Why should I act morally?”, and “What should our goals be?” range far beyond mere cooperation and science’s domain. Moral philosophy’s traditional methods and wisdom remain as relevant and critical as ever. Moral progress resulting from recognizing morality’s grounding in science might even give moral philosophy’s reputation a substantial boost.

Will all such cultural moral systems then be the same if they are consistent with the proposed single universal moral principle? No. Such cultural moral norms would be merely heuristics (usually reliable, but fallible rules of thumb) for the universal moral principle. Depending on a group’s history, environment, and sometimes different goals, the cultural moral norms that are most likely to achieve those goals by “increasing the benefits of cooperation without exploiting anyone” could still be diverse, contradictory, and perhaps even bizarre to other cultures.

Despite such potential diversity, one moral norm will almost certainly have a prominent place in every such morality. That moral norm will be some version of the Golden Rule. Despite its known flaws, the Golden Rule’s ability to initiate the powerful cooperation strategy indirect reciprocity insures it a permanent place in human morality.



The Not So Golden Rule,

Found: a Universal Moral Principle,

Moral Universals from An Evolutionist’s Perspective,

A Universal Principle Within Moralitys Ultimate Source,

A kind of normativity: What all well-informed, rational people would endorse as universally moral

In Found: a universal moral principle I argue science reveals 1) the ultimate source of morality is the species independent cooperation/exploitation dilemma and its solutions, and 2) there is a necessary component of all those solutions to the cooperation/exploitation dilemma relevant to human morality. That necessary component of all these solutions is the cross-species universal moral principle we can express as “increase the benefits of cooperation without exploiting others”.

If the above claims are true, would all well-informed, rational people endorse this principle as universally moral? It seems they must do so; to do otherwise would be irrational.

Now consider Bernard and Jason Gert’s definition of “normative” in the Stanford Encyclopedia of Philosophy entry “Morality”:

“… the term ‘morality’ can be used … normatively to refer to a code of conduct that, given specified conditions, would be put forward (endorsed) by all rational persons.”

By the Gert definition, “increase the benefits of cooperation without exploiting others” is “normative”. This principle provides an objective definition of what ‘is’ universally moral regardless of the needs, preferences, and opinions of people or any other being.

However, as described in Found: a universal moral principle, this normativity – this principle’s scope of moral authority – is limited. This bit of science is silent on critical elements necessary for defining well-functioning cultural moral codes.

The principle is silent on who ought to be included in “others” (the people in our “circle of moral concern” as Peter Singer describes them) who are not to be exploited. Are “others” just your family, your tribe, everyone, or everyone plus all conscious creatures? Singer summarizes human moral progress as “expanding the circle of moral concern”, and this moral principle from science does not appear to even address what size that circle of moral concern ought to be.

The principle is also silent on what benefits of cooperation we ought to pursue. For example, should that benefit be well-being or flourishing for all, or ought each person cooperate with and not exploit others with the goal of increasing their personal well-being and flourishing?

Of perhaps special concern to philosophers, the endorsement of this principle as universally moral by all rational people is not due to it having innate binding power or moral authority. Its moral authority must come from cultural enforcement in societies that choose it as a moral reference for refining their moral codes and from the motivating emotional power of the moral sense of people who practice the principle. Endorsement of the principle as universally moral also does not imply that following this moral principle will always be rational or best meet the needs and preferences of the individual.

Endorsement also does not imply agreement by all rational people on what constitutes “exploitation” or any of other the other innumerable aspects of implementing the principle in a specific society’s moral code.

Looking at the big picture, science only tells us about what ‘is’. Given human needs and preferences, science can inform us as to how we can be most likely to achieve them. What we ‘ought’ to do regardless of our needs and preferences – what morality is commonly thought to be about – is a different category of thing. What the moral principle “increase the benefits of cooperation without exploiting others” does is ground discussions about what morality ‘ought’ to be in what science tells us morality ‘is’.

Readers may be thinking this moral principle is just too vague to be of much use. But arguably the most powerful cooperation strategy known is indirect reciprocity. And perhaps the most effective heuristic for initiating indirect reciprocity is “Do to others as you would have them do to you”. Note this form of the Golden Rule, like the moral principle, is silent on what benefits will be and who is included in “others”. Nevertheless, societies that follow the Golden Rule can do very well even when individuals may have different goals for moral behavior.

As an example of its potential utility, this science offers a new understanding of the normative power (the moral authority) of the Golden Rule. When acting on it will increase the benefits of cooperation, all well-informed, rational people should (I argue) endorse it as universally moral.

Insights into human rights from science


“Consider the range of issues covered by the Universal Declaration of Human Rights, which recognizes personal rights to life, nationality, recognition before the law, protection against torture, and protection against discrimination on such bases as race and sex; legal rights to a fair trial, the presumption of innocence, and protections against ex post facto laws, arbitrary arrest, detention or exile, and arbitrary interference with one’s family, home, or reputation; a comparable variety of civil liberties and political rights; subsistence rights to food and health care; economic rights to work, rest and leisure, and social security; social rights to education and protection of the family; and the right to participate in the cultural life of the community. A comprehensive account of these rights would require that we combine, at minimum, the perspectives of law, political science, economics, and sociology—plus philosophy, if we want to understand the conceptual foundations of human rights and the justifications for this particular list.”  Donnelly, Jack (2013). Universal Human Rights in Theory and Practice. Cornell University Press


Certainly “the perspectives of law, political science, economics, and sociology—plus philosophy” contribute to our understanding of the foundations of human rights and their justifications. But they do not necessarily do so more than science does. This essay explains how the ultimate source of morality, including the idea of “human rights”, is illuminated, explained, and grounded by science.

Science of the last 50 years or so supports the reality of a species independent universal moral principle we can state as “Increase the benefits of cooperation without exploiting others.” (See Found: A Universal Moral Principle.)

Human rights are part of human morality, but what do rights such as life, liberty, and the pursuit of happiness (as listed in the American Declaration of Independence) have to do with cooperation? Consider the idea that enforcing a human right is a kind of reciprocity strategy. I’ll respect your right to life, liberty, and the pursuit of happiness, and you respect mine. And if you don’t respect other people’s rights, the society will collectively punish you for it and we will also work to insure the government does not violate these rights. We have thus described a prime example of indirect reciprocity, arguably the most powerful cooperation strategy known. The benefit of cooperating to enforce these specific rights is that we all get to pursue, with limits we will discuss in a moment, life, liberty, and the pursuit of happiness.

What about human ‘rights’ to the necessities of life such as food, shelter, and medical care? Can we coherently argue such rights exist? Enforcing such ‘rights’ requires a transfer of resources from people with more property to those who have less. This transfer is not live and let live reciprocity.  Also, some argue we have an innate right to “property” and this “right” is the source of standard moral norms against theft. (“Do not steal” is another good example of a reciprocity strategy that increases the benefits of cooperation in societies – I won’t steal, you don’t steal, and we punish those who do.)

So we have conflicting proposed ‘human rights’ to property and to the necessities of life. What insights can science’s universal moral principle shed on how to resolve what is, at bottom, a moral conflict about how we ought to live?

As described in Found: A Universal Moral Principle, the above universal moral principle, which is purely a product of science, does not have any strange power of innate bindingness or moral authority regardless of our needs and preferences. Its moral authority first comes from cultures and individuals who advocate and enforce it as a moral reference because they expect it will meet their needs and preferences better than their alternatives. Once a part of a cultural morality, this principle can then gain emotionally binding moral authority and thus become motivating (regardless of one’s needs and preferences in the moment of decision) when it is incorporated into the moral sense of individuals.

So what does this tell us about conflicting proposed ‘human rights’? It tells us that the bindingness and moral authority of human rights comes from cultures and individuals enforcing these ‘rights’ as better meeting shared needs and preferences than not enforcing them. Perhaps philosophers will come up with a more persuasive case for a different source of bindingness and moral authority for human rights. But until they do, what science tells us about human rights – simple as it is – may be the most useful information we have on the subject.

Of course, it is not necessarily simple to determine how to best define and enforce human rights which are in conflict. For that, the help of the perspectives of law, political science, economics, sociology, and especially philosophy are needed. The simple part is the justification from science for calling them human rights and for enforcing them;  we enforce them because we believe doing so will increase the benefits of living in our societies.


Found: a universal moral principle

Darwin Showing Eve the Inner Workings of the Tree of KnowledgeDarwin inviting Eve to examine the inner workings of the
Tree of Knowledge of Good and Evil

Illustration by Julia Suits


Behaviors motivated by our moral sense or advocated by past and present moral codes can be called descriptively moral, meaning described as moral in one culture but perhaps immoral in others. Are some of these behaviors and norms actually universally moral, as our intuitions tell us, or will that question be forever debated? Does being universally moral somehow require a behavior to also be innately obligatory regardless of our needs and preferences, or are universality and being obligatory independent qualities of morality?

This essay answers these questions while proposing the following. 1) All cooperation problems relevant to morality share a common ultimate source in the cooperation/exploitation dilemma: how to sustainably obtain the benefits of cooperation without exploitation destroying future benefits of cooperation. 2) This dilemma implies a universal moral principle. Both the dilemma and its implied universal moral principle are innate to our natural world.

Searching for morality’s ultimate source

Descriptively moral behaviors, such as those motivated by our moral sense and advocated by past and present cultural moral norms, make up much of the data set we can use to test hypotheses about the origin and function of ‘moral’ behavior. Here, ‘moral’ is in quotes because these judgements and norms are contradictory, sometimes strange, and some, such as the more than thousand year old Viking moral norms regarding raiding monasteries and villages, are morally horrifying to modern sensibilities.

Could identifying the ultimate source of these descriptively moral behaviors shed light on what is universally moral?

There has been a growing consensus over the last 50 years or so that descriptively moral behaviors are biologically and culturally selected for by the benefits of cooperation in groups they produce[2,,5,6,11,17,19]. So is evolution the ultimate source of descriptively moral behaviors? Evolution is only the process that biologically encodes certain behaviors in our moral sense and culturally encodes them in moral norms. There is nothing universally moral about evolution’s processes of variation, selection, and replication, or even increasing reproductive fitness, preserving species, or preserving “life”. These processes and these goals can be accomplished by immoral as well as moral means.

Let’s try a higher level of causation.

Could the cooperation strategies that evolution is encoding be morality’s ultimate source? Winning cooperation strategies can include morally despicable exploitation of out-groups. So, again, there is nothing universally moral about cooperation strategies in general and no obvious subset of universally moral behaviors.

But there is arguably one more level of causation. Consider the problem that is solved by these cooperation strategies.

Morality’s ultimate source in the cooperation/exploitation dilemma

In our physical reality, large benefits of cooperation are commonly available. However, initiating cooperation exposes one to exploitation, meaning someone accepting help or goods but not reciprocating either directly or indirectly. Exploitation is almost always the winning strategy in the short term and can be in the longer term. But exploitation and the conflict it produces can make cooperation unsustainable. These circumstances create a universal cooperation/exploitation dilemma. How can species overcome exploitation’s short term “winning” hand in order to sustainably obtain the large benefits of cooperation?

This cooperation/exploitation dilemma must be solved by all beings that form highly cooperative societies.

Fortunately for us, our ancestors chanced upon elements of strategies, including reciprocity strategies and displays of moral virtues, which solved this dilemma. (Moral virtues such as courage, magnanimity, and humility are markers of being a reliable person to cooperate with as well as being elements of strategies to resolve conflict[5]..) Biological evolution encoded these solutions in our moral sense and cultural evolution encoded them in our moral norms.

Our ancestors thus discovered “morality”. Even a flawed understanding of morality has enabled us to become the incredibly successful social species we are.

Reciprocity strategies are perhaps the most effective means found to date for overcoming the cooperation/exploitation dilemma. Game theory shows [1,3,4,15,18]  that reciprocity strategies have three necessary elements: motivation to risk initiating cooperation (helping), motivation to punish exploitation or otherwise reducing the benefits of cooperation (though that punishment[11] may be just shaming or shunning), and criteria for when to do both.

Biological evolution’s implementation of reciprocity strategies in our moral sense appears to have specifically encoded: 1) our motivating “helping” emotions[10] compassion, gratitude, and loyalty, 2) our motivating “punishing” emotions[10] contempt, disgust, anger, shame, and guilt, and 3) circumstances that cross-culturally trigger right/wrong moral judgments[9]:: care/harm, fairness/cheating, loyalty/betrayal, authority/subversion, and sanctity/degradation.

Cultural evolution’s implementations of elements of reciprocity strategies in cultural moral codes[8,11] are far more diverse than that in our moral sense’s underlying biology. Nevertheless, we can still identify the three necessary elements. We find 1) advocacy for initiating cooperation, such as “Do to others as you would have them do to you”, “Defending other people and your country is a moral obligation”, and “Do not kill, steal, or lie” (cooperate by not doing these things even when you really want to), 2) advocacy for punishment of moral norm violations such as “an eye for an eye”, enforcing justice as part of rule of law, and shaming those who violate group marker norms such as sexual and food taboos, and 3) definitions of circumstances that trigger cooperation and punishment such as “Has harm been done to someone in one of my in-groups?”, “Is someone disrespecting my in-groups’ markers of morally required hair style, dress, behavior, or sacred beliefs?”, “In time of war, don’t cooperate with enemies”, and “If people break the law, leave punishment beyond shaming and shunning to the law”.

But what about Buddhist “loving kindness” and Christian “forgiveness” rather than “punishment” as the most moral responses to exploitation and harm to others? People are more complex than game theory’s simple agent models. A common goal encoded into our moral sense is to be a member of cooperative groups. Understanding why people act in anti-social ways and, in essence, inviting them back into a cooperative relationship with the group can therefore sometimes be a successful replacement for “punishment” as a component of strategies to overcome the cooperation/exploitation dilemma.

We can explain the existence of all these specific motivating emotions, moral norms, and circumstance triggers as selected for by the benefits of cooperation they produced.

Since this cooperation/exploitation dilemma is innate to our natural world, it reveals the ultimate source of descriptively moral behaviors independent of biology, evolution, game theory, and human thought.

Could it also reveal what is universally moral?

Universally moral ‘means’

There appears to be a subset of strategies that are a necessary part of all strategies that sustainably solve the cooperation/exploitation dilemma. Even strategies that exploit or war against out-groups[17] must begin by cooperating in an in-group[7].  In order to maintain sustainable cooperation in the in-group, others within that in-group are not exploited.

Thus we have a behavior that is necessary to all descriptively moral behaviors: “Solve the cooperation/exploitation dilemma without exploiting others”. Since it is necessary to all descriptively moral behaviors, it is universally moral among human moral behaviors.

For example, direct and indirect reciprocity strategies that exploit no one are universally moral. And as already referred to, displays of ‘pagan’ virtues such as courage, magnanimity, and leadership, and ‘Christian’ virtues of humility, meekness, quietude, asceticism, and obedience can solve cooperation problems both by being markers of reliable cooperators and improving conflict resolution[5].  Thus, display of moral virtues can also overcome the cooperation/exploitation dilemma without exploiting anyone and are universally moral.

Culture specific implementations of these strategies will commonly differ in the strategies emphasized, definitions of in-groups where cooperation is focused and out-groups with less intense cooperation, markers of membership in both, heuristics for advocating initiating cooperation and punishing exploiters, and the moral virtues that are emphasized. It is the strategies themselves that are universally moral, not their implementations in different cultures.

Also, note this is a definition of moral ‘means’ (moral actions), not moral ‘ends’. Aside from a vague goal of “overcome the cooperation/exploitation dilemma”, this principle is silent about moral ends. But could a definition of only moral means be the basis of culturally useful moral codes? Consider that versions of the Golden Rule, moral heuristics favored around the world, are effective moral guides with no stated end or purpose. Kantianism’s categorical imperatives are examples from traditional moral philosophy of other moral principles that also only define moral means. The lack of a stated end for morality does not prohibit a culturally useful moral code.

Why might a society prefer to advocate and enforce an evolutionary morality based on this universal moral principle above all others? While science cannot tell us what we ought to do in an ultimate sense, science can inform us how we are most likely to fulfill our needs and preferences. Societies could decide to advocate for and enforce such an evolutionary morality because they expect many of their needs and preferences can be best met by increasing cooperation in their societies consistent with this universal moral principle:

First, the principle advocates increased cooperation which directly increases material benefits and, perhaps more importantly, increases emotional rewards triggered by cooperation, particularly cooperation with family and friends.

Second, cooperation strategies are innately harmonious with our moral sense and emotionally motivating since our moral sense was selected for by cooperation strategy benefits.

Also, this moral principle is an objective reference for resolving disputes about morality because its definition is a product of objective science.

Would most of us prefer to be guided by some traditional moral code or philosophy with mysterious burdensome obligations or an evolutionary morality devoted to increasing the benefits of cooperation? Further, what secular goal might we prefer for a moral code except increasing the benefits of living in our society, and what other moral principle is universally moral as a matter of science?

In addition, it can be culturally useful to better understand what is merely descriptively moral and not universally moral. For example, once a food or a sexual behavior avoidance has become common for whatever reasons, food and sex taboos can become merely markers of membership[13,14] in an in-group. Religious people in particular may still feel strongly that such moral norms must remain part of their personal morality, but intellectually knowing that these are in a sense arbitrary should encourage consensus on not including them in public morality enforced by the society as a whole.

Also, it could be useful to understand that moral norms such as “Do to others as you would have them do to you” and “Do not kill, steal, or lie” are not universally moral when acting on them would decrease the benefits of cooperation (and thus not solve the cooperation/exploitation dilemma). Intellectually understanding these are only fallible heuristics by, again, religious people in particular could increase consensus about when and how to enforce them as part of public morality. For example, this understanding could increase consensus regarding abortion, euthanasia, and morality in time of war when the Golden Rule is abandoned.

On its own, “Solve the cooperation/exploitation dilemma without exploiting others” is not a useful moral guide for daily life. People need something more specific. “Increase the benefits of cooperation without exploiting others” may be slightly more useful. “Increase the benefits of cooperation by doing to others as you would have them do to you” advocates initiating indirect reciprocity by a reassuringly familiar moral guide with a twist that makes it universally moral.

As mentioned, responding to immoral behavior with “loving kindness” and forgiveness rather than shaming, shunning or more severe punishment may sometimes be more likely to actually “increase the benefits of cooperation” (be moral). Knowing when “loving kindness” and forgiveness is the most moral action when dealing with others, as well as when dealing with our own personal failings, is a subject ripe for study.

The components of morality as solutions to the cooperation/exploitation dilemma can be conceptually understood as shown in Figure 1.

Figure 1Figure 1. Morality in science: innate, mathematical, intellectual, and observed


Objections to this universal moral principle

Couldn’t kin selection solve this dilemma as appears to be the case for social insects that also form highly cooperative societies? What part does kin selection have in moral universals?

What separates moral norms from other cultural norms is the common feeling (and practice) that violators deserve punishment[11]. Punishment of violators is a necessary component of all reciprocity strategies. However, kin selection (also called kin altruism) such as altruistically helping and caring for our children can be evolutionarily stable (a winning strategy) without any ‘violator’ punishment component. Kin selection has a different relationship to human morality than reciprocity strategies and the moral virtues described above.

You say this moral principle from science is not innately binding. Then what makes it “moral”? And in any case, aren’t you committing the naturalistic fallacy?

This principle is “moral” because it is a necessary component of all solutions to the cooperation/exploitation dilemma relevant to human morality, meaning relevant to our moral sense and cultural moral codes.

Objections to a morality’s lack of innate bindingness arise from the natural feeling produced by our moral sense that our moral judgements are strangely binding and obligatory regardless of our needs and preferences. Why do people feel this way?

People naturally feel “that there is an objective higher code to which we are all subject” because our ancestors who felt like this were better cooperators[16]. Our predecessors whose neurobiology did not trigger bindingness feelings for moral norms tended to act more selfishly, obtained fewer benefits of cooperation, and mostly died out. Natural variation, selection, and replication produced this well-known, but too often still mysterious, illusion of bindingness. The common illusion that what is moral must be innately binding provides no rational basis for rejecting the proposed moral universal.

Innate bindingness and universality are independent qualities of this moral principle. The former is an illusion; the latter is real.

The “naturalistic fallacy” when referring to the is-ought problem is the fallacy that we can derive an ‘ought’ only from what ‘is’, perhaps from what ‘is’ natural or the product of evolutionary processes[20]. Since the proposed universal moral principle makes no claim for innate bindingness (what we somehow ‘ought’ to do), it does not commit the naturalistic fallacy.

Aren’t there philosophical arguments against the existence of moral universals?

Some philosophers have objected to the idea of a universal morality based on the diversity, contradictions, and strangeness of the elements and qualities of human morality. John L. Mackie proposed that the best explanation of these puzzling observations is that these merely “reflect adherence to and participation in different ways of life”[12] which suggests that there are unlikely to be facts about what is universally moral.

As already described, science can now explain 1) the observed variations in moral views, 2) our “intractable” opinions about morality and why morality’s quality of bindingness is so strange, and 3) specifically when and why our “special faculty of moral perception or intuition” triggers moral judgements. Mackie’s objections have been answered by science.

Would moral philosophers who accept this proposed moral principle’s universality be out of a job?

No, this universal principle does not supersede moral philosophy; it provides a new grounding for moral philosophy. The bare claim is “strategies that overcome the cooperation/exploitation dilemma while exploiting no one are universally moral”. A tremendous amount of philosophical work would be required for this principle to become culturally useful. This work might be particularly productive for increasing human flourishing due to 1) its grounding in science, 2) its core function of increasing the benefits of cooperation, and 3) its innate harmony with our moral sense. Some needed study areas are listed below. Items 4) through 11) may be largely unexplored philosophical ground.

Philosophical work would still be needed to 1) propose who ought to be included in “others” who are not to be exploited, 2) justify goals (which science is silent about) for the cooperation those strategies enable, 3) propose what our moral obligations are to care for animals and ecosystems, 4) clarify how to coherently apply this moral principle to interactions between groups and within hierarchies, 5) clarify what is morally admirable, merely moral, immoral, and morally neutral, 6) translate the cooperation/exploitation dilemma versions of “cooperation” and “exploitation” into human moral terms, 7) integrate this universal moral principle into existing philosophical moral systems, such as utilitarianism (it defines moral ‘means’ for utilitarianism’s moral ‘ends’) and virtue ethics (it defines virtuous interactions with other people), 8) investigate implications for human rights and justice as fairness, 9) investigate implications for the morality of other solutions to the cooperation/exploitation dilemma such as money economies and rule of law, 10) use all this knowledge to suggest refinements to  cultural moral norms in societies with different histories and in different environments, and 11) suggest when inevitable moral norm contradictions due to different applications of the strategies are best just tolerated.

Also, this universal moral principle illuminates only the subdomain of “ethics” that covers moral means for interacting with other potential cooperators. This universal principle is not sufficient to answer larger philosophical questions which may be dependent on ultimate goals such as “How should I live?” and “What is good?”

Figure 2 illustrates science’s universally moral ‘means’ as a new foundation for ethics. Note that money economies and rule of law are also solutions to the cooperation/exploitation dilemma. Their morality can be judged by the universal moral principle in the same way cultural moral norms can be judged.

Ethics grounding in scienceFigure 2 A new foundation for ethics



  1. Axelrod, R. (1984). The Evolution of Cooperation. New York: Basic Books.
  2. Bowles, S., Gintis, H. (2011). A Cooperative Species: Human Reciprocity and Its Evolution. Princeton University Press.
  3. Boyd, R., Richerson, P. (1992). Punishment Allows the Evolution of Cooperation (or Anything Else) in Sizable Groups, Ethology and Sociobiology, 13:171-195. DOI: 10.1016/0162-3095(92)90032-Y
  4. Boyd, R., Gintis, H., and Bowles, S. (2010). Coordinated punishment of defectors sustains cooperation and can proliferate when rare, Science, 328, 617-620,
  5. Curry, O. S. (2007). The conflict-resolution theory of virtue. In W. P. Sinnott-Armstrong (Ed.), Moral Psychology (Vol. I, pp. 251-261). Cambridge, Massachusetts: MIT Press.
  6. Curry, O. S. (2016). Morality as Cooperation: A problem-centred approach. In T. K. Shackelford & R. D. Hansen (Eds.), The Evolution of Morality. Springer.
  7. Fu, F., et al. (2012). Evolution of in-group favoritism. Scientific Reports 2, Article number: 460. doi:10.1038/srep00460
  8. Gavrilets, S., Richerson, P. J. (2017). Collective action and the evolution of social norm internalization. PNAS vol. 114, no. 23
  9. Graham, Jesse, Haidt, J., et al. (2012). Moral Foundations Theory: The Pragmatic Validity of Moral Pluralism. Available at
  10. Haidt, J. (2003). The moral emotions. In R. J. Davidson, K. R. Scherer, & H. H. Goldsmith (Eds.), Handbook of affective sciences. Oxford: Oxford University Press. (pp. 852-870).
  11. Harms, W., Skyrms, B. (2010) Evolution of Moral Norms. In Oxford Handbook on the Philosophy of Biology ed. Michael Ruse. Oxford University Press
  12. Joyce, R. “Mackie’s Arguments for the Moral Error Theory” The Stanford Encyclopedia of Philosophy, <;
  13. McElreath, R., Boyd, R., Richerson, P. (2003). Shared Norms and the Evolution of Ethnic Markers. Current Anthropology, Vol. 44, No. 1. pp. 122-130
  14. Meyer-Rochow, V. B., (2009) Food taboos: their origins and purposes. Journal of Ethnobiology and Ethnomedicine. 5:18
  15. Nowak, M. A. (2006). Five Rules for the Evolution of Cooperation. Science, 314(5805), 1560-1563. doi: 10.1126/science.1133755
  16. Ruse, M., & Wilson, E. (1985). The evolution of morality. New Scientist, Oct 17, 1478.
  17. Tooby, J., and Cosmides, L. (2010). Groups in Mind: The Coalitional Roots of War and Morality, from Human Morality & Sociality: Evolutionary & Comparative Perspectives, Henrik Høgh-Olesen (Ed.), Palgrave MacMillan, New York, pp. 91-234.
  18. Trivers, R. L. (1971). The evolution of reciprocal altruism. Quarterly Review of Biology, 46(1), 35-57. doi: 10.1086/406755
  19. Tomasello, M., & Vaish, A. (2013). Origins of Human Cooperation and Morality. Annual Review of Psychology, 64(1), 231-255. doi: 10.1146/annurev-psych-113011-143812
  20. Wilson, D. S., Dietrich, E., Clark, A. B. (2003). On the inappropriate use of the naturalistic fallacy in evolutionary psychology. Biology and Philosophy, 18(5), 669–681.

A Culturally Useful “Evolutionary Morality” from Morality’s Ultimate Source


This essay was first published on The Center for Humans and Nature’s website in response to their call for answers to the question “What can Evolution Tell Us about Morality?”

Like the others found at the link, this essay is based on the science of the last 45 years or so that shows that morality is a human adaptation  that increases the benefits of cooperation. Here are three clarifying responses to a few standard objections to deriving a moral principle from science. The proposed moral principle is:

  • Only a claim about what ‘is’ rather than what imperatively ought to be – so there is no necessary is/ought problem
  • Implied by a perhaps new perspective that the ultimate source of morality is a cross species universal dilemma, the cooperation/exploitation dilemma, which all species must solve if they are to achieve highly cooperative societies.
  • The moral principle that groups could decide to advocate for and enforce because they expect doing so will best meet the group’s needs and preferences.


What can Evolution Tell Us about Morality?

Well, first of all, the process of evolution itself is certainly not the ultimate source of morality. Evolution is only the process that encodes behaviors in our moral sense and cultural moral codes that increase the benefits of cooperation in groups—the apparent function of morality in human cultures. There is nothing necessarily moral in an absolute sense about these behaviors as is illustrated by the diversity, contradictions, and bizarreness of past and present cultural moral codes.

Game theory has revealed cooperation strategies, such as direct and indirect reciprocity, whose elements appear to be universally encoded in our moral sense and cultural moral codes. But game theory also reveals the cooperation benefits of dividing people into preferred in-groups and ignored, or even exploited, out-groups. There is nothing necessarily moral, again in an absolute sense, about cooperation strategies that exploit out-groups.

But consider the problem these cooperation strategies are solving. Could that problem itself be the ultimate source of morality?

In our physical reality, large benefits of cooperation are commonly available. However, initiating cooperation exposes one to exploitation. Exploitation is virtually always the winning strategy in the short term and can be in the long term. However, exploitation makes cooperation unsustainable. These circumstances set up a cross-species universal cooperation/exploitation dilemma. How can species overcome exploitation’s short term “winning” hand in order to sustainably obtain the large benefits of highly cooperative societies?

Fortunately for us, our ancestors came across reciprocity strategies, such as direct and indirect reciprocity, that solve this dilemma. All such strategies include two elements: motivation to risk initiating cooperation and motivation to punish exploitation, though that punishment may just be public shaming or shunning. Encoding these solutions into our biology and cultural norms enabled us to become the incredibly successful social species we are. Since this cooperation/exploitation dilemma is innate to our physical reality, it defines an ultimate source of morality independent of biology, evolution, and game theory.

Further, there appears to be a cross-species universal subset of strategies that solve the cooperation/exploitation dilemma. These are strategies that exploit no one, that only advocate cooperation and punishment of exploitation.

This cross-species universal subset of strategies defines a candidate universal moral principle: “universally moral behaviors are elements of strategies that overcome the cooperation/exploitation dilemma without exploiting anyone.”

But the cooperation/exploitation dilemma is merely a claim about what “is” and the universal subset of strategies that solve it only define universally moral “means.” What our ultimate goals somehow “ought” to be is beyond science’s domain. Can we actually define a morality just based on moral “means” without specifying moral “ends?”

For many people, religious and secular alike, their best compact summary of morality is some version of “Do to others as you would have them do to you.” No goal is stated. All that is described is moral “means”—it is silent about moral “ends.” Knowledgeable Christians should be able tell you that Jesus said this version of the Golden Rule summarizes morality. This is an example of a moral principle that does not have to specify a goal in order to be culturally useful.

This version of the Golden Rule is also highly relevant. It is the best heuristic (imperfect as it is) I am aware of for initiating indirect reciprocity, arguably the most powerful strategy known for overcoming the cooperation/exploitation dilemma. So, if you follow the Golden Rule, you are already following a cross-species universal morality that is inherent to our physical reality.

Why might a group decide to advocate and enforce such an evolutionary morality? While science cannot tell us what we ought to do, science can tell us how we are most likely to achieve our needs and preferences. Many of our needs and preferences can be best met by cooperating with others. Groups could decide to advocate for and enforce such an evolutionary morality because they expect it to best meet their needs and preferences.

Of course, there would still have to be a tremendous amount of philosophical work done to go from the above universally moral “means” claim to the set of moral norms that would define a coherent, well-functioning cultural morality in all its complexity. In any event, the above statement of the principle underlying this candidate “evolutionary morality” might be worth exploring further.



Naturalization of Morality by Moral Facts from Science

Moral naturalism in modern moral philosophy proposes there are “natural facts” of one sort or another that provide an objective basis for what is and is not moral. Relevant science of the last 45 years or so supports the existence of such facts. However, I have never seen such natural facts specifically called out. Below is my proposed list of five. They provide a basis for morality that I find appealing. Comments are welcome.

In the following, “benefits of cooperation” are shared goals achieved by cooperation. “Indirect reciprocity” advocates punishment of “free-riders” along with cooperation with others regardless of whether they are expected to directly reciprocate. Additional explanatory information is in parentheses.

1) In our physical reality, benefits of cooperation are commonly available, and they can be particularly large for intelligent species.

2) However, initiating cooperation exposes one to exploitation by “free-riders”, those who accept help but refuse to provide help to others. (Exploitation of others is always a winning strategy in the short term and sometimes can be in the long term. Exploitation destroys motivation for cooperation and thus opportunities to obtain the benefits of cooperation.)

3) The above circumstances create the cross species universal cooperation/exploitation dilemma: how to sustainably obtain benefits of cooperation without being exploited.

4) Cooperation strategies such as “indirect reciprocity” solve this universal cooperation/exploitation dilemma and are encoded in our moral sense and cultural moral norms. (The benefits of cooperation made possible by indirect reciprocity are the selection force for elements of indirect reciprocity encoded in our biology and cultural norms. For example, the emotions empathy and loyalty motivate initiating indirect reciprocity. But for indirect reciprocity to be maintained, exploiters must be punished. Thus we must expect that violators of these elements of indirect reciprocity, whether encoded into our biology or in cultural norms, will be commonly thought to deserve punishment. Cultural norms and judgments whose violation are commonly thought to deserve punishment are called moral norms and moral judgments in all cultures. This is the way science grounds the human moral sense and cultural moral codes in natural facts.)

5) Strategies such as indirect reciprocity that overcome our universe’s innate cooperation/exploitation dilemma without exploiting others are universally moral, both empirically among people and theoretically for all intelligent beings.

Consider “Do not kill, steal, or lie”. These are norms whose violations are commonly thought to deserve punishment. These admonitions are heuristics (usually reliable, but fallible, rules of thumb) for elements of indirect reciprocity. Each of us is admonished to not do these things to other people, even when we really want to, and they are expected to reciprocate and not do them to us.

Perhaps the most powerful known heuristic for indirect reciprocity is “Do to others as you would have them do to you”. Jesus is quoted as saying it summarizes morality. Science now tells us why it does.

The morality of applying the Golden Rule has been rightly criticized for certain circumstances, such as when dealing with criminals and in time of war or simply “when tastes differ”. Understanding the Golden Rule is a heuristic for indirect reciprocity clears up a lot of confusion. First, the Golden Rule advocates initiating a cooperation strategy. If you are not seeking to cooperate in some sense with a criminal or an enemy in time of war, it would make no sense to apply it. Second, when “tastes differ” and you know others would not like done to them what you would like done to you, then strictly following it would initiate conflict, not cooperation. Finally, the Golden Rule is not a moral principle. It is an incredibly useful, but fallible, heuristic for choosing moral behavior.

But what about moral norms that exploit out-groups such as “Women must be submissive to men” and “Homosexuality is evil!” or are markers defining favored in-groups such as “Cutting your hair disrespects God” or “Eating pigs is an abomination!”? Empirically, these moral norms are not universally considered moral. Theoretically, they are not universally moral to the extent they exploit out-groups. If we prefer morality that is universal, then we can cheerfully reject all of these norms as either immoral or morally irrelevant.

Like the rest of science, 1) to 5) are all ‘is’ claims. How do we know they are the basis for what morality ‘ought’ to be? We don’t. Science tells us nothing about what we imperatively ‘ought’ to do or what our goals ought to be. Moral philosophers remain fully free to continue pursuing perhaps unanswerable questions about what morality ‘ought’ to be. This science about morality is useful for the following reasons. It reveals strategies for achieving commonly shared goals such as increased well-being, saving the environment, and many other goals through increased cooperation. Also, since these strategies are what largely shaped our moral sense and codes, following their imp0lied morality will be uniquely motivating. Finally, since these strategies solve the cross-species universal cooperation/exploitation dilemma, they can be expected to be recognized as moral ‘means’ by all sufficiently advanced intelligent beings and that universality is, in itself, attractive.

The moral binding power of this science comes from un-mysterious sources: the social force of cultures that advocate and enforce such a morality, the motivating power of our individual moral sense, and the intellectual charm of a universal, internally coherent morality.

Cultures need moral codes in order to survive and prosper. On the one hand we can choose moral codes based on the morality that is innate to our universe. On the other hand, we can define our morality based on theism, whatever our cultural morality happens to be, or on perhaps unanswerable philosophical questions such as “What is good?”, “How should I live?” and “What are my obligations?”. Or since this science based morality makes no claim to define what we imperatively ‘ought’ to do, is the implication that we can choose only one of these possibilities a false choice?

Perhaps at least theists and philosophers asking the above questions (which are both interesting and important) could improve the coherence and usefulness of their work by integrating in what science tells us morality ‘is’: solutions to the universal cooperation/exploitation dilemma. Theists might even describe this science as the morality encoded into our physical universe by a benevolent god and thus available to all intelligent beings from the beginning of time to the end of time.