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Can we have knowledge in ethics, or are moral judgements something other than candidates for truth and knowledge?

Assess whether there can be moral knowledge, contrasting cognitivism and non-cognitivism and weighing intuition, reasoning and disagreement as routes to or against it

A focused answer on the possibility of moral knowledge. Cognitivism versus non-cognitivism, whether moral claims can be true, the routes of intuition and reasoning, and what persistent moral disagreement implies for moral knowledge.

Generated by Claude Opus 4.811 min answerUpdated 2026-06-06

Reviewed by: AI editorial process; not yet individually human-reviewed

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Quick answer

Moral knowledge requires moral judgements to be truth-apt and justifiable. Cognitivism says moral judgements express beliefs that can be true or false; non-cognitivism (emotivism, prescriptivism) says they express attitudes or prescriptions, so strictly there is nothing to know. For cognitivists, justification might come from rational intuition (criticised as mysterious), moral reasoning and reflective equilibrium, or inference from facts about wellbeing (constrained by the is-ought gap). The argument from persistent disagreement is the main challenge, but it can be resisted: much disagreement rests on non-moral facts or framing, there is convergence on core norms, and disagreement also exists in fields we call knowledge. A defensible verdict is modest cognitivism: defeasible moral knowledge of core claims is possible.

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What this dot point is asking

SEAB wants you to assess whether moral knowledge is possible. This is the central question of the ethics area, and it depends on two prior questions: whether moral judgements can be true at all, and if so, how we could be justified in holding them. Your task is to set out the cognitivism versus non-cognitivism divide that frames the first question, examine the proposed routes to moral justification, and weigh the argument from persistent disagreement that is often thought to settle the matter against moral knowledge.

The answer

What moral knowledge would require

Knowledge, on the standard analysis, is justified true belief. So moral knowledge requires that moral judgements be capable of truth (otherwise there is nothing to know) and that we can be justified in holding the true ones. The question of moral knowledge therefore splits into two: are moral judgements truth-apt, and can they be justified? The first is answered by the cognitivism debate, the second by examining the routes to moral justification.

Cognitivism and non-cognitivism

Cognitivism holds that moral judgements express beliefs that purport to describe moral reality and are therefore true or false. To say "cruelty is wrong" is, on this view, to assert something that can be correct or incorrect. Non-cognitivism holds that moral judgements do not express truth-apt beliefs but rather attitudes or prescriptions: emotivism says they express approval or disapproval (roughly, "cruelty, boo!"), and prescriptivism says they commend or condemn action ("do not be cruel"). If non-cognitivism is right, then strictly there is no moral fact to know and no moral knowledge in the standard sense, only the expression and coordination of attitudes. So the possibility of moral knowledge hangs largely on this debate.

Routes to moral justification

Suppose cognitivism is right and moral claims can be true. How might we be justified in them? Three routes are proposed. Rational intuition: some hold we directly grasp certain self-evident moral principles, much as we grasp simple logical truths; critics object that intuitions vary across cultures and that the faculty is mysterious. Moral reasoning: we argue from principles we accept to conclusions about cases, and refine both, a process often described as reflective equilibrium, in which we adjust principles and particular judgements until they cohere. Inference from facts: we reason from facts about wellbeing, harm and human nature, though always constrained by the is-ought gap, which means facts alone cannot entail values without an evaluative premise.

The argument from disagreement

The leading argument against moral knowledge is the argument from persistent disagreement. Moral disputes seem deep and intractable in a way factual disputes are not: societies and individuals disagree profoundly about contested issues with no agreed method of resolution. Some conclude that this is best explained by there being no objective moral truth to know, only differing attitudes. This is a powerful challenge precisely because the disagreement looks so durable.

Replies to the disagreement argument

The argument can be resisted. Much moral disagreement turns out to rest on disagreement about non-moral facts (the consequences of a policy, the nature of an entity) or on framing, rather than on ultimate values, so it is less purely moral than it appears. There is also wide cross-cultural convergence on core norms (against gratuitous cruelty, betrayal, and unfairness), which an error-theory of all moral judgement struggles to explain. And disagreement exists in domains we still count as knowledge, including frontier science and history, so disagreement alone does not entail the absence of truth. The defensible upshot is a modest cognitivism: there can be defeasible moral knowledge of some core claims, reached by reasoning and reflective equilibrium, even if secure foundations remain hard to establish.

Arguing for modest moral knowledge against the disagreement objection

Step 1: State the objection

The objector argues: moral disagreement is deep and persistent; the best explanation is that there is no objective moral truth; so there is no moral knowledge. This is the argument from disagreement.

Step 2: Question the explanation of disagreement

Reply that much apparent moral disagreement is not ultimate. People who differ on a contested policy often share the underlying value (reducing harm) but disagree about the non-moral facts (what will actually reduce harm). Once the factual dispute is settled, the moral gap narrows, so the disagreement does not show divergence in values.

Step 3: Point to convergence

Note the wide cross-cultural agreement on core norms: prohibitions on gratuitous cruelty, betrayal of trust, and gross unfairness recur across societies. If there were no moral truth, this convergence would be a puzzling coincidence; it fits better with there being some moral facts that inquiry tends to track.

Step 4: Neutralise the inference from disagreement

Observe that disagreement also exists in fields we count as knowledge, such as cutting-edge physics and contested history. Since we do not infer from disagreement there to the absence of truth, disagreement in ethics does not by itself license that inference either.

Step 5: Reach the modest conclusion

Conclude that there can be defeasible moral knowledge of core claims, justified by reasoning and reflective equilibrium, even though foundations are contested and some hard cases remain unresolved. The disagreement objection shows moral knowledge is difficult and incomplete, not impossible.

Common traps

Assuming the question is settled by disagreement alone: Disagreement is evidence, not proof; it can stem from factual or framing differences, coexists with convergence on core norms, and exists in fields we count as knowledge.
Treating cognitivism as obviously true: Whether moral claims are truth-apt is exactly what non-cognitivism denies. The possibility of moral knowledge depends on this and must be argued.
Forgetting the is-ought constraint: Justifying moral claims by appeal to facts cannot proceed by deriving an ought from a pure is; an evaluative premise is always needed.
Confusing intuition with mere feeling: The rational-intuition route claims a cognitive grasp of self-evident principles, not just an emotional reaction; the objection is that it is mysterious and variable, which must be addressed, not assumed.

Examples in context

Example 1. Reflective equilibrium on a hard case. Faced with a difficult dilemma, a reasoner tests a general principle (always tell the truth) against a strong particular judgement (you may lie to a murderer seeking a victim). The clash forces revision: perhaps the principle is qualified, or the judgement reconsidered, until principles and cases cohere. This process illustrates a route to moral justification that does not rely on mysterious intuition or on deriving values from bare facts, and it can yield defeasible moral knowledge.

Example 2. Disagreement dissolving into facts. Two people fiercely disagree about whether a development should proceed; one favours it, one opposes. On examination, both value the community's wellbeing equally and differ only about the empirical effects of the project. The dispute is largely factual, not a clash of ultimate values. The example shows how the argument from disagreement is weakened once apparent moral disputes are traced to non-moral facts.

Try this

Q1. Explain why the possibility of moral knowledge depends on whether moral judgements are truth-apt. [6 marks]

Cue. Knowledge is justified true belief, so it needs a truth-apt content; if non-cognitivism is right and moral judgements only express attitudes, there is no moral truth to know, so no moral knowledge in the standard sense.

Q2. Explain what reflective equilibrium is as a route to moral justification. [8 marks]

Cue. It is the process of adjusting general moral principles and particular judgements against each other until they cohere, justifying moral beliefs by their mutual fit rather than by foundational intuition or by deriving them from bare facts.

Q3. Give two replies to the argument from moral disagreement. [6 marks]

Cue. Any two of: much disagreement rests on non-moral facts or framing, not ultimate values; there is wide convergence on core norms; and disagreement also exists in fields we count as knowledge, so it does not entail the absence of truth.

Exam-style practice questions

Practice questions written in the style of SEAB exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.

Original20 marksIs moral knowledge possible? Discuss.

Show worked answer →

A strong answer first notes that moral knowledge requires moral claims to be capable of truth (so it presupposes cognitivism) and to be justifiable. So the question splits: can moral judgements be true, and if so, how could we be justified in them?

Set out cognitivism (moral judgements express beliefs that are true or false) versus non-cognitivism (they express attitudes, emotions or prescriptions, not truth-apt beliefs, so strictly there is nothing to know). Note that if non-cognitivism is right, moral knowledge in the strict sense is impossible, though moral reasoning and consistency are still possible.

For cognitivists, assess the routes to justification: rational intuition of self-evident principles (criticised as mysterious and culturally variable); moral reasoning from agreed principles and cases, including reflective equilibrium (adjusting principles and judgements until they cohere); and inference from facts about wellbeing and harm (constrained by the is-ought gap).

Weigh the challenge from persistent disagreement: deep, seemingly intractable moral disagreement is taken by some to show there is nothing objective to know. Reply that much disagreement turns on non-moral facts or framing, that there is wide convergence on core norms, and that disagreement also exists in domains we count as knowledge.

Judgement: defend a position, for example a modest cognitivism on which there is defeasible moral knowledge of some core claims reached by reasoning and reflective equilibrium, while acknowledging the difficulty of foundations. Markers reward the cognitivism-non-cognitivism split, the routes to justification, the disagreement argument and reply, and a decided conclusion.

Original12 marksExplain the difference between cognitivism and non-cognitivism in ethics, and why it matters for whether there can be moral knowledge.

Show worked answer →

The expected answer defines cognitivism: moral judgements express beliefs that purport to describe moral facts and are therefore true or false (truth-apt). It defines non-cognitivism: moral judgements do not express truth-apt beliefs but rather attitudes, feelings or prescriptions, for example expressing approval (emotivism) or commending an action (prescriptivism).

Explain why it matters for moral knowledge: knowledge is standardly justified true belief, so it requires a truth-apt content. If non-cognitivism is right, moral judgements are not the kind of thing that can be true or false, so there is, strictly, no moral fact to know and no moral knowledge in the standard sense, only the expression and coordination of attitudes.

Add nuance: even non-cognitivists can allow for moral reasoning, consistency, and a kind of correctness relative to our attitudes; and some hybrid and quasi-realist views try to recover talk of moral truth within a broadly non-cognitivist framework.

Judgement-style close: whether moral knowledge is possible depends largely on whether moral judgements are truth-apt, which is exactly what divides cognitivism from non-cognitivism. Markers reward precise definitions with examples (emotivism, prescriptivism), the link from truth-aptness to the possibility of knowledge, and the nuance about quasi-realism.