How science tells us when it would be immoral to follow the Golden Rule


Versions of the Golden Rule such as “Do to others as you would have them do to you” are found in cultures around the world. They provide the best moral guidance many people have. In the Christian New Testament, Jesus is quoted as saying this version summarizes “the law and the prophets” (Mathew 7:12), meaning it summarizes morality.

But cultures routinely abandon the Golden Rule in war when soldiers try to kill the enemy, when dealing with criminals (the judge will not free the criminal just because the judge would like to be freed), and when “tastes differ” – when not everyone wants to be treated the same way. People who must abandon the Golden Rule when it is their chief moral compass can become susceptible to their worst inclinations for cruelty, particularly in time of war and when dealing with criminals.

So the Golden Rule is not perfect. And when it is abandoned due to those imperfections, people who use it as their chief moral compass can do truly horrendous things. But what moral standard can we compare the Golden Rule against to tell us when it is likely to advocate immoral behavior?

Everyone knows that science can describe the evolutionary functions (the principle reasons they exist and persist) of our hearts, eyes, and other organs. For example, the primary functions of our heart and eyes is to pump blood and to see.

Some people are aware that science can similarly tell us the evolutionary function of the biology underlying our moral sense. As described below, the primary reason our moral sense exists is that the behaviors it motivates increase the benefits of cooperation in groups. Our pre-civilization ancestors who did not have a strong moral sense tended to die out because they were not motivated to be good cooperators.

Fewer people are aware that the function of behaviors advocated by past and present cultural moral norms is the same as that of our moral sense – to increase the benefits of cooperation in groups. Cultural moral norms that are not as effective at increasing cooperation tend to not be imitated and to be abandoned in favor of more effective ones.

Could knowing the evolutionary function of our moral sense and cultural moral codes provide the guide we need to tell us when following the Golden Rule would be immoral?

There has been a surprisingly long history of understanding “social morality” (behaviors motivated by our moral sense and advocated by past and present moral codes) as elements of cooperation strategies. (I hope this explicit definition of social morality will reduce needless confusion with broader scope philosophical definitions of ‘morality’, ‘moral’, and ‘immoral’. Answers to moral philosophy’s important questions such as “What is good?”, “What are my obligations?”, and “How should I live?” can range far beyond this discussion’s limited domain of social morality as cooperation strategies.)

Almost 150 years ago, Charles Darwin proposed that the primary reason our moral sense exists is that the behaviors it motivates were selected for by the benefits of cooperation they produce.

“A tribe including many members who, from possessing in a high degree the spirit of patriotism, fidelity, obedience, courage, and sympathy, were always ready to aid one another, and to sacrifice themselves for the common good, would be victorious over most other tribes; and this would be natural selection.”

But Darwin was not the first to propose morality as cooperation. In the fourth century BCE, Plato described the Greek philosopher Protagoras’ explanation to Socrates that the function of our moral sense (the primary reason it exists) is to enable people to gain the benefits of cooperating in groups. This was the message of the Greek myth Protagoras retold about how everyone got their moral sense. Socrates did not respond to Protagoras’ morality as cooperation claim. If Socrates had seriously engaged with it, western philosophical thought might have taken a very different path.

Why would there be a Greek myth about the function of morality being cooperation? Before the emergence of money economies and rule of law, the most effective available means for obtaining necessary benefits of cooperation would have been acting morally and maintaining a good moral reputation. Before the arrival of morality defining religions, the connection between morality and the benefits of cooperation would have been even more obvious. Morality as cooperation has likely been a common view for most of human history.

Modern insights from science into social morality – behaviors motivated by our moral sense and advocated by cultural moral codes – strongly support Protagoras and Darwin’s morality as cooperation claims.

In the current literature:

Based on the available science, the philosophers Kim Sterelny and Ben Fraser conclude in their paper on objective moral truth that “… moral facts are facts about cooperation, and the conditions and practices that support or undermine it”.

Oliver Curry’s Morality as Cooperation theory is based on seven culturally universal moral behaviors. These behaviors are helping kin, helping your group, reciprocating, being brave, deferring to superiors, dividing disputed resources, and respecting prior ownership.

Moral Foundations Theory (Jonathan Haidt, Jesse Graham, and others) describes six cross-culturally moral foundations found to be universal in human societies. These foundations are Care/Harm, Fairness/Cheating, Loyalty/Betrayal, Authority/Subversion, Sanctity/Degradation, and Liberty/Oppression. These foundations appear to be circumstances that trigger moral judgments and behaviors with the function of increasing the benefits of cooperation in groups.

And emotions triggered by our moral sense have been identified (by Jonathan Haidt and others) as empathy, gratitude, anger (righteous indignation), disgust, guilt, shame, and “elevation” (a pleasurable experience of optimism and pride). These emotions motivate helping that initiates or maintains cooperation and punishment (of other’s or one’s own) behaviors that decrease, or potentially decrease, the benefits of cooperation.

Finally, we have the full social morality data set: the diverse, contradictory, and bizarre behaviors motivated by our moral sense and advocated by past and present cultural moral codes. That diversity, contradiction, and bizarreness is primarily explained as implementations of different cooperation strategies such as: 1) different definitions of favored ingroups and less favored or even exploited outgroups, 2) different markers of membership in and commitment to each group, such as food and sex taboos, clothing and hairstyles, and respect for sacred authorities and objects, and 3) emphasis on different cooperation strategies such as direct and indirect reciprocity, hierarchies, kin altruism, and demonization of outgroups as threats.

The above all support the conclusion that no matter how superficially diverse, contradictory, and bizarre social morality may appear, its function (the primary reason our moral sense and cultural moral codes exist) is to increase the benefits of cooperation in groups.

Consider again “Do to others as you would have them do to you”. It is normally highly effective moral advice for increasing the benefits of cooperation.

A little game theory knowledge reveals why versions of the Golden Rule are and will remain such highly effective moral guides. The Golden Rule advocates helping (if one would like to be helped in that circumstance), and not harming, all people one meets. In cooperative societies, such norms are reciprocated by others and this reciprocity is maintained by punishment, as either moral violations or law violations, of people who violate that society’s norms. That is, the Golden Rule advocates initiating indirect reciprocity, arguably the most effective cooperation strategy known.

Knowing morality’s function tells us that versions of the Golden Rule are heuristics (usually reliable, but fallible, rules of thumb) for increasing the benefits of cooperation by indirect reciprocity.

Behaviors that decrease the benefits of cooperation contradict social morality’s function and thus are inherently socially immoral.

By enabling us to cooperate effectively, our social morality has made us the incredibly successful social species we are. Accessing the benefits of cooperation is the principle reason societies exist. Could there be a more appropriate criterion for socially moral or immoral than increasing or decreasing cooperation benefits? Perhaps, but I am not aware of any yet proposed.

While not directly answering all moral questions, this definition of socially moral and immoral provides the basis of a culture independent moral system. In my own life, I am finding that the moral guidance “increase the benefits of cooperation without exploiting others” works well. Perhaps other people will find the same.

What about other intelligent species from the past, present, or future?

As I described in A Universal Principle Within Morality’s Ultimate Source (link below), a cooperation/exploitation dilemma is innate to our physical reality. That dilemma is how to sustainably obtain the benefits of cooperation without exploitation destroying future benefits of cooperation. This is a dilemma because exploitation is virtually always the winning strategy in the short term and can be in the long term. All beings that form highly cooperative societies must solve this dilemma. Fortunately, cooperation strategy solutions to this dilemma are as innate to our universe as the dilemma they solve.

Due to different biology and history, other intelligent species might judge desirable “benefits” of cooperation differently, and we cannot be sure who will be in their circles of moral concern. However, we can confidently expect intelligent species from the past, present, or future to all have a social morality with the same function, increasing the benefits of cooperation.

We now have the potential to understand the origin, function, and underlying principles of our moral sense and cultural moral codes as part of objective science. Perhaps this knowledge can help provide the moral guidance needed to save humanity from the environmental and social disasters our greed and ignorance are bringing down on us.


Some resources:

Darwin, Charles (1871) The Descent of Man and Selection in Relation to Sex. p.166 London: Murray, 1st edition

Curry O.S. (2016) Morality as Cooperation: A Problem-Centred Approach. In: Shackelford T., Hansen R. (eds) The Evolution of Morality. Evolutionary Psychology. Springer

Graham Jesse, Haidt Jonathan, et al. (2013) Moral Foundations Theory: The Pragmatic Validity of Moral Pluralism.

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).

Plato (4th century BCE) Protagoras Dialog

Sloan, Mark (2018) A Universal Principle Within Morality’s Ultimate Source

Sterelny, Kim and Fraser, Ben (2017) Evolution and Moral Realism. Advances in Experimental Social Psychology Volume 47, 2013, Pages 55-130

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