8. Can we know what is right? | Quomodo Scimus : IBTOK

The Core Theme - Knowledge and the Knower

Lesson 8 - Can we know what is right? (Ethics 2)

The previous lesson asked what knowing obliges you to do. This lesson asks whether there is such a thing as moral knowledge to be obliged by in the first place. Maybe we should have done this lesson first?

TOK is not philosophy, but this lesson is philo heavy and full of (largely) famous dead philosophers. I apologise in advance but all my IB students also do the Swiss Matu and our Swiss Matu has philosophy as a compulsory subject. And Swiss Matu philo is largely about ethics. Ergo this lesson.

Lessons 1 and 2 asked what knowledge is. Lessons 3 and 4 asked how perspective shapes it. Lessons 5 and 6 asked how it is produced and why even careful reasoners go wrong. Lesson 7 asked what knowing obliges you to do - and assumed, in asking that question, that the concept of moral knowledge makes sense. This lesson pulls back to the prior question. Before you can know what is right, you need to establish that moral knowledge is possible at all. This turns out to be less obvious than it seems.

Two challenges frame the lesson. The first is from Karl Marx, who argued that what a society calls moral tends to reflect the interests of those who hold power, not an independently discoverable truth. The second is from the Scottish Enlightenment philosopher David Hume, whose is/ought gap shows that no description of how the world is - however complete and accurate - can logically entail a claim about how it should be. If both are right, moral philosophy may not be doing what it thinks it is doing. The rest of the lesson is a serious attempt to answer them.

Below is the provocation that frames everything that follows. Conisder it before reading on.

"The philosophers have only interpreted the world, in various ways; the point is to change it."

Karl Marx, Theses on Feuerbach (1845), Thesis XI

Marx wrote these eleven theses as a private notebook in 1845. He was 26 years old and had not yet written any of the works he is now remembered for. He never published them himself, Friedrich Engels found them in a notebook after Marx's death and published them in 1888. Thesis XI is now engraved on Marx's tomb in Highgate Cemetery, London.

Marx is making a claim about the function of philosophy in a society. Philosophy tends to produce sophisticated justifications for the world as it is rather than tools for changing it. I actually think this is true of many social sciences taught in school: this is the way of the world, this is how it works. (School history is dangerous because it shows that another world is possible, and that revolutions can happen. In contrast, economics generally explains how a current, particular form of capitalism works and treats it like universal, natural law).

Understanding that does not lead to action has, in some fundamental way, misunderstood itself.

Is Marx right about moral philosophy? Think through your response before reading on. Keep it. You will return to it at the end of the lesson. Does studying ethics - in this lesson or anywhere else - change what you do, or only what you can say about what you do? And if it has not changed what you do, what does that mean for the status of moral knowledge?

THE PROVOCATION

The Question Before the Question

Is moral knowledge possible?

Marx's challenge is political and historical. What a society calls moral tends to reflect the interests of those who control its institutions, its language, and its production of ideas. As I have explained in our history lesson, he argues that the ruling ideas of every epoch are the ideas of the ruling class. In this view, moral philosophy does not discover what is right. It elaborates and legitimises what those with power have already decided to call right. In this respect you can understand how Gramsci (who we encountered in Big idea 1 in Lesson 4) is very much part of the Marxist tradition.

In contrast, Hume's challenge is logical. In A Treatise of Human Nature (1739), he observed that moral and philosophical arguments routinely move without justification from statements about what is - descriptions of how things are - to statements about what ought to be - prescriptions about what should be done. This logical gap cannot be closed by factual knowledge alone, however complete. No amount of knowing how the world is tells you, by itself, how it should be.

Marx and Hume are making related but different versions of this move. Hume identifies a structural feature of moral argument: the leap from description to prescription that cannot be underwritten by evidence alone. Marx identifies a sociological pattern: the tendency of that leap to land wherever class interest directs it.

The four frameworks at the centre of this lesson are each trying to give moral reasoning a more secure foundation and they are illustrated by the NotebookLM infographic below. Kant argues that the foundation is rational and derived from reason alone, which makes it independent of both cultural context and class interest. Mill argues that it is empirical and grounded in evidence about consequences. Aristotle argues that it is practical and embedded in character and developed through experience in a way that is not a knowledge claim in the conventional sense at all. Appiah, finally, argues that the past itself provides the answer, in that moral progress is real, and that is the strongest available evidence that something like moral knowledge exists.

Three big ideas about what knowing obliges you to do.

Big idea 1 - Moral knowledge is derived from reason, not from consequences or culture

Kant's categorical imperative is a test for whether any proposed rule can qualify as a moral law.

"Act only in accordance with that maxim through which you can at the same time will that it become a universal law."

Immanuel Kant, Groundwork of the Metaphysics of Morals (1785), AK 4:421

For Kant, moral claims cannot derive their authority from consequences, because consequences are unpredictable and culturally variable. A morality grounded in what people in a particular time and place happen to value has no claim to the universality that knowledge requires. Kant argues that genuine moral knowledge must be universal and necessary, which means it must be grounded in reason rather than in experience.

The categorical imperative is a procedure for testing whether a proposed maxim can qualify as a moral principle. Consider the maxim: "I will use AI to write my assignments and present the work as mine." Apply the universalisability test: if everyone did this, the entire system of assessment that gives qualifications their meaning would collapse. Grades would no longer measure anything. A diploma obtained this way would be worthless. The same logic applies from another angle. Your teacher, your examiner, and your future employer are being used as means - deceived into making judgments on the basis of false information about your capabilities - rather than treated as rational agents entitled to accurate information. The issue is not what bad things would happen if everyone did this, but what kind of maxim can coherently function as a moral law. This is rational and Kant's second formulation. "So act that you use humanity, whether in your own person or in the person of any other, always at the same time as an end, never merely as a means." - Immanuel Kant, Groundwork of the Metaphysics of Morals (1785), AK 4:429

Immanuel Kant - The Categorical Imperative
Thinking About Stuff

Immanuel Kant (1724–1804) was a German Enlightenment philosopher from Königsberg who reshaped modern thought. His categorical imperative is a universal moral law: act only on maxims you could will to be universal, and treat humanity always as an end, never merely as a means. Rejecting consequences as the basis of ethics, Kant grounded morality in reason and duty. His major works, including Critique of Pure Reason, argue that knowledge arises from the mind structuring experience.

The second formulation is often easier to apply to concrete cases. A person used purely as an instrument for someone else's purposes - without regard to their own ends, their own standing as a rational agent - is being wronged in a way that the categorical imperative identifies precisely. This is why the Huntington's case in Lesson 7 is a moral dilemma as much as a medical one: the daughter is being treated as someone whose interests do not count in the calculation. She is being used as a means to the father's emotional comfort rather than recognised as a person with her own claim to knowledge about her own life.

The challenge Kant poses to Marx is direct. If moral knowledge is a priori - derived from reason alone - then it is the same for everyone regardless of class position. The universalisability test is not the property of any ruling class: it exposes any maxim that privileges one group over another as a maxim that cannot be universalised without self-contradiction. Whether Kant succeeds in this is contested. But the response to the ideological critique is serious and has not been refuted by pointing to his historical context alone.

Big idea 2 - Moral knowledge is empirical - it depends on understanding what actually promotes human wellbeing

Mill agrees with Kant that morality is not just custom. He disagrees about where moral knowledge comes from. For Mill, it comes from evidence about consequences, not from reason alone.

"... actions are right in proportion as they tend to promote happiness, wrong as they tend to produce the reverse of happiness. By happiness is intended pleasure, and the absence of pain; by unhappiness, pain, and the privation of pleasure."

John Stuart Mill, Utilitarianism (1863), Chapter II

Utilitarianism - CrashCourse

This episode uses the Batman/Joker dilemma to introduce utilitarianism and contrast it with Kantian ethics. It explains the principle of utility - the greatest good for the greatest number - and the distinction between act utilitarianism and rule utilitarianism. The thought experiment (shoot one prisoner to save nineteen, or refuse and let all twenty die) illustrates both the logic and the demands of the theory. It connects to the drowning child argument in Lesson 7: if you are in a position to prevent harm at relatively low cost to yourself, the utilitarian calculus requires you to act.

For Mill moral knowledge is in the domain of empirical inquiry, you know what is right by understanding what produces the best outcomes for everyone concerned. The right action in any situation is the one that promotes the most happiness across all the people it affects. Mill is careful to resist the reduction of happiness to mere physical pleasure. He distinguishes between higher and lower pleasures - between the satisfactions of intellectual and aesthetic life and those of appetite - and argues that the higher pleasures are genuinely superior, a claim he grounds in the judgment of those who have experienced both. Someone who has learned to read carefully, to follow an argument, or to listen to music with attention consistently prefers those activities to passive consumption - not because they are more pleasant in a simple sense, but because they engage capacities that, once developed, make the simpler pleasures feel thin by comparison. If you are trying to follow this argument and you get it, you will understand what I mean. It is better, Mill writes, to be Socrates dissatisfied than a fool satisfied. Moral knowledge requires understanding not just how much happiness an action produces but what kind.

The connection to my previous lesson is clear. Singer's drowning child argument is a Millian argument: the mathematics of happiness does not change with distance. If you can prevent serious suffering at modest cost to yourself, the utilitarian calculus is the same whether the person suffering is in front of you or on the other side of the world. This is one of the most productive implications of Mill's framework and, as Lesson 7 established, one of the most demanding.

As the Crash Course film above makes clear, the problem with consequentialism is the one Mill shares with all frameworks that evaluate actions by their outcomes: consequences are complex and often unknowable in advance. In addition, the requirement to aggregate happiness across all affected parties can, in some interpretations, justify harming a small number of people for the benefit of a larger number - producing conclusions that seem clearly wrong even to people who find the framework compelling in the abstract (cf. the Jim thought experiment). Mill was aware of this and worked to defend utilitarianism against it, arguing that the principle, properly applied, generates strong protections for individual rights. Whether that defence succeeds is one of the central debates in moral philosophy.

The challenge Mill poses to Marx is less direct than Kant's but equally serious. Mill is a materialist in the broad sense: like Marx, he looks at the world rather than at pure reason. But the utilitarian standard, consistently applied, points toward greater equality rather than toward the interests of any ruling class. A system that produces misery for the majority in order to sustain comfort for a minority fails the utilitarian test by any honest accounting. Mill was a liberal reformer who believed that rigorous empirical moral reasoning and progressive political change pointed in the same direction. Mill was clearly never a Marxist, but he certainly ended up as a democratic socialist concerned about the injustice of the capitalist world that he lived in.

Big idea 3 - Moral knowledge is practical wisdom - developed through character, not derived from principles

Aristotle asks a different question from both Kant and Mill: not what reason demands, or what produces the best outcome, but what kind of person you should become.

"the human good turns out to be activity of soul in accordance with excellence (and if there are more excellences than one, in accordance with the best and the most complete). But furthermore it will be this in a complete life."

Aristotle, Nicomachean Ethics, Book I (trans. Rowe)

Aristotle's starting point is eudaimonia - a Greek word usually translated as happiness or flourishing, but meaning something closer to living well and doing well as a human being. Eudaimonia refers to the full exercise of distinctively human capacities in accordance with 'virtue'. Aristotle begins with the question of what the best kind of human life looks like, and how it is achieved. Moral philosophy, for Aristotle, is the inquiry into that question. Watch the following episode from Crash Course which also builds on Kant and Mill.

Aristotle and Virtue
CrashCourse

Born in 384 BCE in Stagira, he studied under Plato, later tutoring Alexander the Great. He founded the Lyceum in Athens and made lasting contributions to ethics, logic, biology, and politics. Aristotle argued that virtue is a habit developed through practice, aiming at a mean between extremes of excess and deficiency, guided by reason. Courage, for example, lies between rashness and cowardice. Living virtuously leads to eudaimonia, often translated as flourishing or well-being.

Moral excellence, for Aristotle, is a stable condition of character that allows a person to perceive what a situation requires and to respond appropriately, reliably, and without excessive deliberation. This condition is acquired through practice and habituation rather than derived from principles. Aristotle makes the mechanism explicit: "we become just by doing just things, moderate by doing moderate things, and courageous by doing courageous things." - Aristotle, Nicomachean Ethics, Book II (trans. Rowe) A builder becomes skilled by building, not by studying the theory of building and then applying it. A musician becomes skilled by playing, not by memorising scales and then performing. Moral competence works the same way: it is built up through repeated practice in which what begins as effortful and deliberate gradually becomes fluent and reliable. This has a direct parallel with what we saw about learning in Lesson 6 - that deliberate practice, over time, transforms explicit knowledge into reliable intuition. It starts in System 2 and becomes automated over time in System 1. For Aristotle, moral knowledge is expertise of this kind.

Marx argued that what a society calls virtue tends to serve ruling-class interests. Aristotle would not fully disagree - he was aware that different societies produce different character ideals. But his account of practical wisdom is a theory of the individual person developing capacities through experience. And phronesis, properly developed, is precisely the capacity to see through ideological justification, to perceive what a situation actually requires rather than what conventional morality, or class interest, says it requires.

Big idea 4 - Moral progress is real - and that implies there is something to be right or wrong about

Kant, Mill and Aristotle each argue that moral knowledge is possible. Appiah produces the evidence. If moral progress is real - not just change, but improvement - then there is something to be right or wrong about.

"It wasn't the moral arguments that were new; it was the willingness to live by them."

Kwame Anthony Appiah, The Honor Code (2010)

Kwame Anthony Appiah's argument in The Honor Code (2010) begins not with philosophical theory but with historical cases. Three practices that were once widespread, legally protected, morally defended, and embedded in the deepest values of their societies were abandoned: duelling in Britain, foot-binding in China, and Atlantic slavery. Appiah's focus is on what kind of event each ending was.

His first observation is that the arguments against these practices were available long before the practices ended. Duelling was always murderous and irrational; foot-binding was always painfully crippling; slavery was always an assault on the humanity of enslaved people. The people who practised them were not ignorant of these facts. The arguments did not change. What changed was something else - something that Appiah identifies as the relation between these practices and the codes of honour through which people understood what it meant to be a person of standing in their society.

Appiah's deeper claim is that these changes were genuine improvements. The abolition of slavery was a genuine moral gain. The end of foot-binding was an improvement, not simply a change in fashion. Future generations will look back at practices widespread in our own time with something like the retrospective horror we now feel about slavery, not because those future cultures will simply be different from ours, but because they will be right about things we are currently getting wrong. Appiah identifies candidates: mass incarceration, factory farming, the toleration of extreme poverty alongside extreme wealth. My own candidate is pre-school children on mobile phones in 2020 that might be viewed by future generations in the same way we view boys smoking in the photographs of Lewis Hine from 1910.

Appiah is careful not to claim certainty about which of these future generations will judge most harshly. Some of what we currently do is morally wrong, we have enough of the relevant evidence to suspect which things, and the fact that we continue to do them does not make them right. The connection to the opening provocation is direct. If Marx is right that moral philosophy is ideology - that it produces sophisticated justifications for the existing order rather than tools for changing it - then moral change is just the replacement of one ideology with another. There is no progress, only succession. But if Appiah is right that abolition was a genuine moral improvement, then there is something to be right or wrong about. Moral claims can be knowledge claims.

Bringing it together

Where the obligations divide

Kant, Mill and Aristotle are each answering a different question, which is what makes them three frameworks rather than three positions in a single debate. Kant asks what reason unconditionally demands of you - what you owe to every rational being regardless of the consequences. Mill asks what produces the best outcomes for everyone affected - what an honest accounting of welfare, suffering, and flourishing shows you ought to do. Aristotle asks what kind of person you are becoming - whether the choices you make repeatedly are building the character of someone who can perceive and respond to what situations require.

Appiah connects the three frameworks to moral reality. If any of them were purely ideological - if moral reasoning were nothing but class interest in disguise - there would be no moral progress, only moral change. The abolition of slavery was the right thing to do. The argument that enslaved people were fully human and therefore owed full moral consideration was correct before it was accepted, correct during the long period when it was resisted, and correct in the eventual recognition that made it normative. Banning under-16s from using social media might turn out to have been the right thing to do. That correctness is what the word progress means.

At the start of the lesson, Marx's Theses on Feuerbach was used as a provocation. Perhaps moral philosophy is just interpretation, and interpretation changes nothing. The lesson has argued that moral knowledge is possible - that Kant, Mill and Aristotle each offer a genuine account of what it might be - and that Appiah's historical evidence suggests it is real. If that is right, Marx's challenge does not dissolve. It sharpens. The question is what you intend to do with it.

The eight lessons of this course have traced what knowledge is, how it is formed, how it can go wrong, what shapes it, and what it demands. This final lesson argues that moral knowledge is part of what it is possible to know, that it is imperfect and contested and developing, and that it creates obligations - as Singer showed in Lesson 7 - precisely because it is knowledge. That is the force of Marx's last thesis, and it is a reasonable place to end.

Next: Optional Theme 1: Language. What is language - and where does it end?

Questions, assessments, films and other stuff.

Questions to think about

Kant argues that moral knowledge is a priori - derived from reason rather than experience. Does this mean that all moral disagreement is the result of reasoning badly? What would it mean for two people to reason correctly and still disagree about what is right?
Mill's utilitarian principle requires comparing and aggregating the wellbeing of different people. Is that possible? If it is not, does the framework collapse entirely, or does it still provide useful guidance even when precise calculation is impossible?
Aristotle argues that moral knowledge is developed through practice and habituation rather than derived from principles. Does this mean that a person raised in a morally corrupt environment cannot know what is right? And what would it mean to correct that deficit in adulthood?
Appiah identifies cases of genuine moral progress in history. What distinguishes real moral progress from mere change in social convention? Is there a principled answer to that question, or only the verdict of hindsight?
Marx claims that what a society calls moral tends to reflect the interests of its ruling class. Apply this critique to any one of the three frameworks in this lesson. Is the framework immune to it, or does the critique land?
Hume argued that you cannot derive an ought from an is. Does Appiah's historical argument about moral progress violate this principle, or does it find a way around it? What kind of claim is "moral progress is real" - is it a factual claim, a moral claim, or both?
Return to what you wrote before reading this lesson. Has the lesson changed your answer? If it has, what changed it - an argument, an example, or something else? And what does your answer to that question say about how moral knowledge, if it exists, is actually acquired?

Exhibition connections
See more exhibition ideas and previous student work here

It is never too early to start to think about your TOK Exhibition, the ideas in this lesson connect strongly to three of the 35 prompts. Start noticing objects in the world around you that speak to these questions.

Prompt #11: Can new knowledge change established values or beliefs? Appiah argues that moral progress has happened and will continue to happen - that what was once morally acceptable became morally intolerable as understanding developed. This is a direct case for how knowledge changes values.

Prompt #13: How can we know that current knowledge is an improvement upon past knowledge? This is the core question for any account of moral progress: what makes the end of slavery an improvement rather than simply a change? Appiah's answer is that the arguments for abolition were correct before they were accepted, which implies a standard independent of social approval.

Prompt #34: In what ways do our values affect our acquisition of knowledge? The Marxist critique in this lesson is an extended answer to this question: if ruling-class values shape what counts as moral knowledge, then the acquisition of moral knowledge is systematically distorted in ways that serve existing power structures. Each framework in this lesson can be read as an attempt to identify and correct for that distortion.

Feature films
For more see my 10 films for the TOK journey page.

🎬 WATCH — Hannah Arendt (2012)
Directed by Margarethe von Trotta

A drama about the philosopher Hannah Arendt's coverage of the Eichmann trial in Jerusalem in 1961 and the concept of the "banality of evil" that followed. Arendt argued that Adolf Eichmann was not a monster in any obvious psychological sense but an ordinary person who had ceased to think - who had replaced moral judgment with bureaucratic compliance and the language of duty to superiors. The film is a study in what it looks like when moral knowledge fails not through malice but through the suspension of judgment.

It connects to Frankfurt (indifference to truth as a moral failure), to Kant (the categorical imperative and what following orders without moral reasoning violates), to Aristotle (phronesis as the capacity to perceive what a situation morally requires, which Eichmann conspicuously lacked), and to the central question of this lesson: what kind of knowledge moral knowledge is, and what prevents people from exercising it. My students can watch the film here.