Is all morality subjective?

If you were asked whether it is wrong to torture an innocent child, your immediate reaction would likely be one of absolute, non-negotiable horror. Yet, if morality is merely a byproduct of human evolution or cultural conditioning, that horror is no more objective than a dislike of broccoli. This is the central tension of moral philosophy: we live our lives as if moral facts are as real as gravity, yet we struggle to find them in the physical world. To answer whether all morality is subjective, we must distinguish between *where our moral beliefs come from* and *whether those beliefs refer to objective truths*. ## The Case for Moral Realism Many philosophers argue that morality is objective, a view known as [Moral Realism](https://plato.stanford.edu/entries/moral-realism/). Realists argue that certain moral claims are true regardless of what any individual or culture believes. Just as the earth was round before humans discovered it, certain actions are wrong regardless of our opinions. The prominent philosopher G.E. Moore argued in his landmark work, *Principia Ethica*, that "good" is a simple, indefinable property that we perceive through moral intuition. Realists point out that when we debate moral issues, such as human rights or justice, we are not merely expressing personal tastes. We are behaving as if there is a correct answer to be found. If morality were entirely subjective, a statement like "slavery is wrong" would merely mean "I dislike slavery," making genuine moral disagreement impossible. ## The Case for Moral Anti-Realism Conversely, defenders of [Moral Anti-Realism](https://plato.stanford.edu/entries/moral-anti-realism/) argue that morality is fundamentally subjective. A major proponent of this view was the Scottish Enlightenment philosopher David Hume, who famously argued in *A Treatise of Human Nature* that we cannot derive an "ought" from an "is." > "Take any action allowed to be vicious: Wilful murder, for instance. Examine it in all lights, and see if you can find that matter of fact, or real existence, which you call vice... The vice entirely escapes you, as long as you consider the object. You never can find it, till you turn your reflection into your own breast, and find a sentiment of disapprobation, which arises in you, towards this action." In the twentieth century, J.L. Mackie championed "Error Theory" in his book *Ethics: Inventing Right and Wrong*. Mackie argued that while our moral language *claims* to be objective, all such claims are actually false because objective moral values simply do not exist in the universe. Ultimately, while our *perceptions* of morality are undoubtedly shaped by subjective factors like culture and biology, the question of whether a fundamental moral reality exists remains one of the most vital debates in philosophy. ## Follow-up questions 1. If evolutionary biology can fully explain why we feel certain actions are wrong, does that completely undermine the argument for objective moral truths? 2. How can moral realists explain the vast and persistent disagreement about moral issues across different cultures and historical eras? 3. If we accept that morality is entirely subjective, on what grounds can we legitimately judge or interfere with the practices of other cultures?

If two people look at the night sky and one sees a flat dome while the other sees infinite space, their disagreement does not prove that the universe lacks a true shape. It merely proves that one of them, or perhaps both, has an incomplete perspective. Moral realists face a formidable challenge: if objective moral facts exist, why do cultures across time disagree so violently on issues like slavery, gender roles, and warfare? To defend their position, realists do not need to claim that moral truths are obvious. Instead, they argue that moral disagreement is not a symptom of subjectivity, but rather a consequence of cognitive limitations, non-moral disagreements, and developmental progress. ## The Illusion of Disagreement: Shared Values, Different Facts One of the most powerful realist counterarguments is that historical and cultural disagreements are rarely about fundamental values. Instead, they are disagreements about *factual, non-moral beliefs*. The contemporary philosopher [Michele Moody-Adams](https://en.wikipedia.org/wiki/Michele_Moody-Adams), in her book *Our Kind of People: Talk and Talk and Talk*, argues that many apparent moral disputes disappear once we isolate the empirical beliefs of the participants. Consider a historical culture that practiced witch trials. To a modern observer, executing an innocent person for witchcraft is a grave moral atrocity. However, the historical actors and the modern observers actually share the same moral principle: *it is wrong to allow dangerous murderers to go free*. The disagreement is not moral; it is empirical. The historical culture believed, as a matter of physical fact, that witches existed and caused real harm. Once the scientific facts are corrected, the moral evaluation aligns. ## Moral Blindness and Cognitive Distortion Just as physical blindness does not disprove the existence of light, "moral blindness" does not disprove the existence of moral facts. Realists argue that self-interest, prejudice, and social conditioning can distort our moral perception. In his paper [“Moral Disagreement”](https://philpapers.org/rec/BRUMD), philosopher David Brink argues that deep-seated biases prevent individuals from apprehending objective moral truths. A society relying on slave labor has a massive economic incentive to rationalize the practice. This is not a lack of objective moral truth; it is a case of motivated irrationality. This perspective positions moral discovery as akin to scientific discovery. For centuries, humanity was mistaken about the nature of disease, attributing it to bad air or divine wrath. We did not conclude that biology is subjective; we recognized that discovering objective truth is difficult. > "The fact of ethical disagreement no more shows that there are no objective moral facts than scientific disagreement shows that there are no objective physical facts." > — David Brink, *Moral Realism and the Foundations of Ethics* ## The Argument from Moral Progress If morality were purely subjective, the concept of "moral progress" would be incoherent. We could say that our moral views have *changed*, but not that they have *improved*. To explain historical disagreement, realists point to a clear trajectory of moral convergence over time. The philosopher Peter Singer famously described this as the ["expanding circle"](https://opil.ouplaw.org/view/10.1093/law:epil/9780199231690/law-9780199231690-e835) of moral empathy. Historically, human empathy was restricted to the tribe. Over millennia, through rational debate and shared experience, that circle has expanded to encompass other races, nations, genders, and increasingly, non-human animals. This persistent, directional movement suggests that humanity is slowly mapping an existing objective moral landscape, correcting its past errors as it gains clearer vision.