Moral philosophy and the science of morality do not study the same thing.

Traditional moral philosophy studies important value and goal questions such as “What is good?”, “How should I live?”, and “What are my obligations?”. These are questions about what moral behavior ought to be.

The science of morality studies the origin and function of “human morality” meaning our moral sense and past and present cultural moral norms. These studies are about what moral behavior ‘is’.

This essay describes how science’s emerging understanding of our moral sense and cultural moral norms provides an objective reference based on the primary reason human morality exists. This moral reference, in the form of two principles, offers a basis for resolving many disputes about which moral norms to advocate and enforce in a culture.

They are moral principles only in the sense of explaining what our moral norms and our moral sense ‘are’. They are not philosophically justified ‘moral principles’ that claim to define what everyone somehow ‘ought’ to do.

These two moral principles are as independent of anyone’s preference and opinion as the rest of science is. Preference and opinion independent moral principles are what the science of morality can provide that moral philosophy cannot. Moral philosophy has only been able to suggest moral principles that remain, to date, matters of preference and opinion despite those principles’ essential roles in our personal and cultural lives.

The scientific moral principles’ usefulness will be illustrated by their ability to clarify disputes about “Eating pigs is an abomination”, “Homosexuality is evil”, and “Do to others as you would have them do unto you”. Revealing how these moral norms ‘work’ provides an objective basis for deciding, regardless of previous opinions and intuitions, which to advocate and enforce to better meet shared goals.

Both the science of morality’s and moral philosophy’s guidance are critical for refining cultural moral norms to best increase human flourishing or to achieve whatever goals are chosen and shared in a society.

Game theory advancements have enabled scientists to finally make sense of the superficial chaos of past and present cultural moral norms plus our moral sense’s judgments and motivations. Human morality exists because it solves cooperation problems. See Oliver Curry’s papers on Morality as Cooperation, Martin Nowak’s book SuperCooperators, and Joshua Greene’s book Moral Tribes for an introduction to the field.

Given goals, science can inform us what we can do to achieve them. The science of morality can do the same. It can help resolve moral disputes by revealing how moral norms ‘work’ and, thereby, which moral norms we should advocate to most likely achieve shared goals.

The Morality as Cooperation literature supports two hypotheses:

1) Culturally moral behaviors are elements of strategies that solve cooperation problems.

2) Universally moral behaviors (behaviors intuitively judged moral by all) are elements of strategies that solve cooperation problems without exploiting others.

Both are arguably ‘true’ (in the ordinary provisional scientific sense) based mainly on their remarkable explanatory power. These principles can explain virtually all known past and present cultural moral norms and our moral sense’s judgments and motivations, no matter how diverse, contradictory, or strange to outsiders.

Assuming we can agree that the above principles define what human morality’s evolutionary function ‘is’, let’s apply this science to the above three examples:

“Eating pigs is an abomination” is a marker strategy for identifying membership in and commitment to a more reliably cooperative in-group.

“Homosexuality is evil” can be doubly effective for increasing cooperation within an ingroup by

1) being a marker of membership and commitment to the ingroup and

2) being a means for exploiting an out-group as an imaginary threat that the in-group must unite to defend against.

And “Do to others as you would have them do to unto you” advocates initiating indirect reciprocity, perhaps the most powerful known cooperation strategy.

The first moral principle confirms that the moral norms about eating pigs and homosexuality are only culturally moral since they exploit others (at least by exclusion) to increase cooperation within a favored ingroup. Simply understanding their arbitrariness and even exploitative and shameful origins provides a basis for rejecting them as counterproductive for achieving a culture’s shared goals.

The Golden Rule can be understood as “universally moral” under the second principle. There is nothing in it implying exploiting or discriminating against others. The Golden Rule, though, is not a moral absolute. It is a heuristic, a usually reliable but fallible rule of thumb.

Since it is a universally moral norm, there should be no disagreements among mentally normal people about the intuitive morality of versions of the Golden Rule. Instead, disputes will be about circumstances when following the Golden Rule might not be moral and, when that happens, what is moral. 

Cultures already commonly abandon the Golden Rule when dealing with criminals, in wartime, and “when tastes differ”. Science can now explain why. In these circumstances, following the Golden Rule will likely create cooperation problems (the opposite of human morality’s function) rather than solve cooperation problems.

Further, moral intuitions often become untethered when the Golden Rule is abandoned in wartime and when dealing with criminals. These untethered moral intuitions (such as wishing to punish or even kill any who harm or threaten our group) can motivate acts that are grossly immoral to modern sensibilities. Wars provide horrendous examples. Too often, even dealings with criminals offer examples of unjustifiable abuse and suffering. Science explains that, even in these circumstances, what is moral remains that which solves cooperation problems. Circumstances that dictate abandoning the Golden Rule can no longer be taken to imply “anything goes” morally.

The above two proposed scientific moral principles can be similarly helpful in resolving a great many disputes about what moral norms will be advocated in a particular culture.

Note that no agreement is required on moral philosophy’s main questions – what our goals or values ought to be. The only requirement for the science of morality to be useful is that there are shared goals that can be better achieved through cooperation.

The cooperation strategies encoded in our moral sense and cultural moral norms are arguably the core of what makes us human and such an incredibly successful social species. Rather than being a burden, science reveals that human morality is a powerful means for maintaining and increasing the benefits of living in societies. Also, since Morality as Cooperation is what shaped our moral sense and cultural moral norms, it defines an innately harmonious personal morality. These are additional reasons why Morality as Cooperation can be a powerful source of moral guidance. 

Is science then sufficient for resolving all moral disputes? No, of course not.

Science is essentially silent about 1) what goals and values a culture or an individual ought to pursue (moral philosophy’s chief focus), 2) even why people ought to prefer moral coherence and what is universally moral over what is merely culturally moral or intuitively feels right, and 3) the important question of who ought to be included in the “circle of moral concern” (who merits full moral respect) that Peter Singer describes in his excellent book The Expanding Circle: Ethics, Evolution, and Moral Progress.

In seeking answers to value and goal questions such as “What is good?”, “How should I live?”, and “What are my obligations?”, philosophers have assembled the well-considered moral wisdom of the ages. Even if those answers remain only matters of opinion and preference, that wisdom is the best source of guidance on ultimate values and goals that we have.

Perhaps you agree with the above; maybe it sounds like nonsense.

In either case, when considering the relative contributions of the science of morality and moral philosophy, I urge you to remember that they study different subjects.

Plainly stating and keeping in mind what the two disciplines study clarifies the separation of their domains and their applicability to refining cultural moral norms versus refining goals and values. This perspective will help clarify how to use both the science of morality and moral philosophy to the best advantage for refining cultural moral norms to achieve whatever shared goals a culture chooses.