What is Moral Skepticism?

What is Moral Skepticism?

Moral skepticism is a group of theories which assert doubts about, or are hesitant to accept the claims of, different moral theories. Most moral theories, if not all, assert the existence of morality in some way. To understand moral skepticism, let’s view a sort of moral theory and see how a skeptic responds.

Some moral theorists claim that good and bad are derived from emotions, and that our emotions are innately programmed to respond positively or negatively to different classes of events and objects. For instance, we usually respond negatively to those who steal from us, and we usually respond positively to those who help the poor and sick; we often call those acts evil and good, respectively. Which means, our emotional responses are not random but are instead universal. And as a result, theorists who believe that then claim good and evil are meaningful and real world properties, but that their reference is to emotional states rather than external states in the world.

So morality is derived from emotion, good and evil are emotional truths in our own minds.

A moral skeptic would respond to this by pointing to instances where that moral worldview seems to not work. As an example, in ancient Sparta it was considered acceptable to do away with the sick, only because they could not fight well. That fact leads the moral skeptic to doubt the appeal to an innate set of emotional responses; that we do not, in fact, respond to the world in a uniform manner. 

The moral skeptic would claim morality is not universal but instead relative to cultures, that cultures condition us to respond positively or negatively to certain events in the world. In Sparta, there were most likely many who viewed their behavior of harming the sick as moral, and thus the harming of others was viewed as a necessary good.

From that, the skeptic could simply assert that good and evil are just linguistic symbols for an ever changing culture, that there is no permanent property in the world which those words refer to. And thus, the skeptic doubts the validity of those words entirely when used to either justify or assert anything regarding “morality”.

So, that is one of the general approaches to moral skepticism. But moral skeptics come in different varieties. We will explore some of those varieties now.

Justified Moral Belief and Action

We deal with the distinction between justified belief and truth all the time in our ordinary lives. There are times where we are justified in our actions, for example, despite our not knowing whether something was true or not. For instance, when we run to help someone because they screamed “help,” we are supposing our actions were justified because of the scream, but we don’t actually know whether someone was really in need of help or not. There is a distinction between being justified and knowing something.

The same sort of thing occurs in morality. That is, some moral skeptics doubt that moral beliefs and moral actions are ever justified.

To start with those who deny justified moral belief, we have non-cognitivism. Non-cognitivism believes moral beliefs do not express truths or falsehoods, and so cannot be justified beliefs. Why? Because when we examine sentences using notions like “good” or “bad” we fail to find a satisfactory set of conditions from which we can determine truth-value. Saying something is “not red” is easily verifiable, but saying something is “not good” is not easily verifiable. Put otherwise, words like “car” refer to something definite in the world. When we say something is a car or not, there are conditions in the world to which the sentence can refer. But that is not the case for moral words or utterances.

So, moral belief cannot be justified since there is no set of conditions in the world to which they definitely refer to.

Now, moreover, when we consider those who doubt justified moral action, we arrive at things like the is-ought distinction. That is, even if we accept the beliefs of some moral worldview as being true, then we are still in need of a justified reason for action.

For example, suppose someone says “stealing is wrong”. Nothing about that sentence entails the necessity of not stealing. In fact, some people might even say,  “stealing is morally wrong; therefore, we ought to do it”.

Which means, not only do moral realists need to convince the skeptics that we can have justified moral belief, but that we can also have justified reasons for moral action. Moral skeptics doubt the justifications given for both belief and action.

Moral Knowledge

Recall that knowledge and belief can be distinct. That we can be justified in our belief that someone needs help, but that we might not know whether said person really needed help or not. This distinction between knowledge and belief means not only are there moral skeptics about justified belief, but also about knowledge.

We can break this down into two kinds: rational moral knowledge and empirical moral knowledge. The moral skeptics doubt both.

Moral knowledge derived from rationality would rely on a methodology of knowing and inference. For instance, a rationalist might say that those who claim moral terms refer to nothing are making no sense whatsoever. For the term “nothing” cannot refer to something, and so it makes little sense to say “nothing refers to nothing”. Thus, the rationalist would dismiss anyone who actively denies the possibility of moral knowledge.

In addition to that, the rationalist might also say that since moral terms cannot be actively denied, it would seem to follow that they may possibly be understood; and so moral knowledge could exist.

In contrast to the rationalist, we have those who make claims to moral knowledge through empiricism. In general those who are empirical about morality try to place morality into biology or sociology. For instance, if some set of rules exist amongst a group of people, of which are about how to behave, then an empiricist can say that those rules constitute morality. And as a result, empirical knowledge about morality can be obtained.

The moral skeptic, however, would deny the assertion of those rules being moral in nature, and perhaps provide some explanation that cuts away the extra layer of moral abstraction from the observational studies of the empiricist.


Much like ordinary skepticism, moral skepticism comes in many different varieties. But both rely on a similar line of reasoning, despite being about different content. Whereas a skeptic in general talks about knowledge more broadly, a moral skeptic focuses more narrowly on matters of good and evil. However, both rely on the same methods of skepticism.

Just as there are skeptics who actively assert the falsehood of worldviews in moral matters, there are those who actively assert the falsehood of worldviews in epistemology more generally. Just as there are skeptics who passively doubt, that is make no positive assertions, in moral skepticism, so too are there passive skeptics in epistemology.

Ultimately, moral skepticism is different in content but the same in argument. There are either skeptics who assert doubts or continuously demand clarification or more axioms: passive skeptics.

Email Notifications


Ideasinhat is a business development analyst and longtime reader of academic literature. He writes books and essays on science and philosophy, and posts them to this website. The essays, as with the books, cover topics from psychology, philosophy, and cognitive science to economics, politics, and law.

Leave a Reply