You're reading


In the TV series “The Good Place”, a deceased philosophy professor called Chidi tries to help his fellow residents of a non-denominational afterlife to become better people by introducing them to problems that moral philosophers worry about. This includes a classic ethical thought experiment called the “trolley problem”:

“Imagine you are driving a trolley when the brakes fail and on the track ahead of you are five workmen that you will run over. Now, you can steer to another track, but on that track is one person who you will kill instead of the five. What do you do?”

Unfortunately for him, Chidi’s efforts are rather undermined when he is immediately placed in the situation of really driving a trolley with failed brakes and has to decide what he will actually do (spoiler alert – he can’t).

As the show points out, people who study ethics, like me and Chidi, love to think about hypothetical situations but can be totally unprepared to make ethical choices in practice. As Michael, another character in the series, puts it: “This is why everyone hates moral philosophy professors… it’s just that it’s so theoretical, you know.”

In The Good Place, Chidi is asked to test his response to the 'trolley problem' inside a real trolley on tracks (Credit: NBC)

So why do people continue studying ethics? One gratifying answer for me and my colleagues would be that it’s because they want to become better people; but this just doesn't cut it. If you need to take an ethics course to become a better person, then there is probably something wrong with you to begin with.

Yet, I believe there is value in attempting to discover ethical principles that could, in theory, be embraced by everybody. Not because this will always make it clear how we should act, but because it helps us to understand ourselves and our societies better – and might even prepare us to tackle the grand challenges of the 21st Century, from climate change to the rise of artificial intelligence.

The quest to identify unifying ethical principles is something that has vexed philosophers for centuries. To understand why, we have to look across the span of human history – from the emergence of law in societies within the last 10,000 years, to the ways that ethics could shape our far future.

You might also like:

Our sense of right and wrong goes back a long way, so it can be helpful to distinguish between ethics and “morality”. Morality is an individual’s, largely intuitive and emotional, sense of how they should treat others. It has probably existed for hundreds of thousands of years, and maybe even in other species. Ethics, on the other hand, is a formalised set of principles that claim to represent the truth about how people should behave. For instance, while almost everyone has a strong moral sense that killing is wrong and that it simply “mustn’t be done”, ethicists have long sought to understand why killing is wrong and under what circumstances (war, capital punishment, euthanasia) it may still be permissible.

Put a small group of people together in relative isolation and this natural moral sense will usually be enough to allow them to get along. However, at some point in our history, human societies became so large and complex that new principles of organisation were needed. Originally these were likely simple buttresses to our pre-existing emotions and intuitions: invoking a supernatural parent might bring together multiple kinship groups or identifying a common enemy might keep young men from fighting each other.

A stone carving inscribed with the laws of Hammurabi (Credit: Getty Images)

However, such buttresses are inherently unstable and attempts to codify more enduring principles began shortly after our ancestors began to form stable states. From the earliest written accounts, we see appeals to what are recognisably ethical values and principles. Take the law code of Hammurabi, written in Babylon in the 18th Century BC, which confidently asserts its author’s intention:

“to bring about the rule of righteousness in the land, to destroy the wicked and the evil-doers; so that the strong should not harm the weak; so that I should... enlighten the land to further the well-being of mankind.”

Early law codes objectified judgements of right and wrong, making them no longer purely matters of opinion

While these are admirable intentions, and speak to our innate sense of fairness, the key ethical development of law codes like this is that they objectify judgements of right and wrong, making them no longer purely matters of opinion. This rule of law not only bound citizens to obey the king, but also bound kings to keep their word and enforce laws consistently and transparently.

The code of Hammurabi also provides one of the first statements of the ethical principle of “Lex Talens” or Proportionality, notably commanding that:

“If a man destroys the eye of another man, they shall destroy his eye. If one breaks a man’s bone, they shall break his bone.”

However, in general it remains merely a list of laws rather than a theory of ethics and embodies a sense of inequality and subjectivity of judgement that runs counter to its universalist intentions. For instance, the above statement only extended to men who owned property, and the code continued with other laws that completely dismiss the humanity of women, such as that if a man causes the death of another man’s wife “his daughter shall be put to death.”

The Golden Rule

It would take more than a thousand years before the first ethical theories emerged between 600 and 0BC. This period, known as the “Axial Age”, saw the rise of philosophical and religious movements across Greece, Israel, India and China that would come to dominate the world.

While these movements had many differences, there were also important points of similarity. This is hardly surprising given that these communities were already well-connected trading partners, but it also reflects that they were trying to solve the same problems, such as how a society formulates principles of ethics and organisation that have genuinely universal appeal.

In Greece and elsewhere during the Axial Age, a principle known as the 'Golden Rule' became a common theme (Credit: Getty Images)

One common theme across all these movements is the "Golden Rule" also known as the principle of reciprocity. For instance:

Avoid doing what you would blame others for doing – Thales of Miletus

What is hateful to you, do not do to your fellow: this is the whole Torah; the rest is the explanation – Babylonian Talmud

If the entire Dharma can be said in a few words, then it is – that which is unfavourable to us, do not do that to others – Padma Purana

Zi gong asked: "Is there any one word that could guide a person throughout life?" The Master replied: "How about reciprocity: never impose on others what you would not choose for yourself?" – The Analects

The fact that so many diverse movements hold this principle in high regard reflects both its simplicity and the self-evidence of both its truth and worth. It clearly says something important about how we ought to live.

Unfortunately, there is much the Golden Rule does not say and it is remarkably hard to apply objectively, because it defines how we should treat people in relation to our own feelings about how we should be treated.

For instance, suppose that we are considering how to treat criminals. We ourselves may never have committed a crime and would thus have no expectation of how we should be treated if we did. This means that we are free to believe things like “if I were a criminal I would expect to be punished severely” and hence deny criminals humane treatment. From such reasoning it is a slippery slope to the wealthy feeling that the Golden Rule justifies their treatment of the poor, military victors believing that it justifies their treatment of the vanquished, misogynists their treatment of women and so on.

A shortcoming of the Golden Rule is that it has done little to prevent acts such as slavery (Credit: Getty Images)

Because of this, Axial Age philosophies invariably supplemented the Golden Rule with a more comprehensive code of ethics, and did so in divergent ways. Some theories, especially in Europe, appeal to the authority of a moral judge (such as a god, ruler or wise human). Other theories, like Confucianism, appeal to the stability of social order and the harmonious relationships of different people. Still others appeal to a conception of human nature, arguing that humans serve a particular role in the Universe and thus we ought to work towards fulfilling this role.

Such appeals are used to justify rules of conduct that determine how we should act day to day. These principles often depart surprisingly little from what came before, continuing to uphold unequal social hierarchies, slavery, misogyny and violence.

Are there any ethical principles with the same self-evident value as the Golden Rule?

Furthermore, these appeals all face the same kind of problem, which Western philosophy identifies with Plato’s dialogue Euthyphro. The difficulty is that if one appeals to any higher authority, order or ideal as grounding the principles of ethics, then one faces a dilemma. On the one hand we might want to say that this authority, order or ideal is inherently just, such that whatever principles flow from it must be correct. However, if we believe this then the principles it produces are essentially arbitrary because we would be required to follow them whatever they were, even if they were not “thou shalt not kill” but “thou shalt kill all the time”. In response to this it is tempting to argue that the authority, order or ideal we are appealing to is justified on some further grounds, such as its benevolence towards humanity. However, if this is so then what we are appealing to cannot be the ultimate source of ethics.

This leaves ethics with a real challenge. Are there any ethical principles with the same self-evident value as the Golden Rule, but that can produce a comprehensive theory of how one should live without needing to appeal to a higher authority or ideal?

This is where modern ethical theory and its peculiar obsessions comes in.

Universal laws and utilitarianism

The last 250 years have seen a flowering of new approaches to ethics. One of these is the argument that ethical principles ought to be duties that everyone could obey as universal laws without exception or contradiction. The philosopher Immanuel Kant proposed that we could identify such principles by imagining the opposite: principles that would contradict themselves if universally applied. To simplify one of his conclusions, he thus proposed that it is never moral to lie under any circumstances because if there were a universal law that lying was acceptable nobody would believe anyone.

Another approach, called utilitarianism, argues that there are certain universal values, such as “well-being”, that we all share and should thus be taken as a universal good. We should design ethical principles that promote these values, and these are principles we will all have reason to endorse.

One approach to deriving ethical principles is to explore how they might work as a universal law that applies to everyone (Credit: Getty Images)

Both approaches offer a combination of coherent moral guidance and a self-evident appeal that go beyond previous ethical thinking. Furthermore, by grounding themselves directly in considerations of what is “right” or “good”, they avoid challenges like the need to appeal to a higher authority.

However, there is just one small problem.

Well, maybe more than one, and maybe not that small…

The first is that these two approaches disagree not only about the foundations of ethical theory but also what people should do. We can see this by revisiting the example with which I opened this article – the “trolley problem” invented by Phillipa Foot in 1967.

Utilitarians endorse the conclusion that we should redirect the trolley, killing one person rather than five. The Kantian tradition does not.

In aiming to maximise well-being, utilitarian views endorse the conclusion that we should redirect the trolley, killing one person rather than five. While killing one person and killing five people are both bad, they argue, killing five is five times worse than one.

The Kantian tradition, on the other hand, evaluates these choices based on how well they would translate into universal laws. Consider the option recommended by utilitarians above: redirecting the trolley away from five people so that it kills only one. As a law, this might be phrased as: “I will sacrifice one person if this allows me to save the lives of more people.”

However, this principle is contradictory because it implies that human lives both have intrinsic value (and so should be saved) and that they can be treated as a means to obtain some other end (and so can be sacrificed). Kant thus believed that any universal law for rational beings would thus have to conclude that killing, like lying, was never justified, even to prevent the death of a greater number of people.

The complexity of the real world is something that theoretical principles can struggle to capture (Credit: Getty Images)

There is a strong tradition of philosophers trying to overcome these differences to produce a unified theory of ethics. However, most philosophers maintain that such a unification is at best a long way off, and that the fierce debate surrounding cases like the trolley problem indicate that it may not be getting any closer.

Another problem is that both utilitarianism and Kantianism are deeply embedded within a set of cultural norms that are reductionist (seeing the world as composed of individual component parts), dualistic (seeing a clear division between right) and individualistic (seeing the goal of ethics as empowering individuals to do the right thing). This is often seen as problematic because such norms are restricted to a small group of Western, Educated, Industrialised, Rich and Democratic (“Weird”, for short) societies and do not reflect the great majority of humanity, so should not be imposed on them.

Developers of artificial intelligence are using cases based on the trolley problem

However, there is a more profound objection to this framing: it is simply inappropriate for guiding ethical decision-making in the real world. Think back to the trolley problem. This involves an individual (the driver) making a simple choice (switch tracks or don’t) whose outcomes are known for certain (either one or five people will die). This example was custom made to provide the perfect framework for evaluating these theories.

Unfortunately, real world ethical problems are not so clear-cut. They invariably involve complex choices with uncertain outcomes and are faced by groups or systems not all powerful decision makers. While a small number of researchers have engaged with the ethics of complexity or the realities of uncertainty, their work is very much an exception.

Will unmanned vehicles follow the best ethical principles when required to balance human lives? (Credit: Getty Images)

This problem becomes especially acute when we move from considering ethical principles for morally inclined people to using these principles to develop ethical algorithms. Right now, developers of artificial intelligence are using cases based on the trolley problem to try and guide the decisions of autonomous vehicles. However, these vehicles must, like all drivers, make decisions in complex and uncertain environments quite unlike the trolley problem. Furthermore, they must be accountable to everyone, and not simply reflect the values and beliefs of their Weird developers.

The future of ethics

Given all this, what might the future of ethics hold? First, let’s consider two possible futures that, as a philosopher of ethics, I would rather avoid.

One of these can be summarised as “more of the same”. People have been trying to produce coherent systems of ethical principles for thousands of years and, while I personally believe that we are now making far more progress towards this than at any previous point in human history, it would be hubris to say confidently that we are incapable of making the mistakes of the past.

Personally, I have no difficulty looking back at periods when ethics was used to uphold the institutions of slavery and violence and saying “that was wrong and those people were mistaken”. However, the same tensions that we can observe in the earliest codification of laws still appear to dog ethics to this day. On the one hand, philosophers are seeking principles of justice that serve the interests of humanity. On the other hand, these appear at best to hold out the prospect of limited moral progress while continuing to promote, or at least obscure, the interests of the privileged and the powerful.

To tackle an issue as significant as climate change, we will need ethics (Credit: Getty Images)

A second future is in many ways bleaker, although I’m not sure it isn’t preferable. In this scenario, not only does the project of producing a coherent ethical theory fail, but the entire field of philosophical ethics collapses. Perhaps people get fed up with our theoretical musings, or maybe we move to a more data-driven society that undermines our faith in the existence of the independent humanistic values that ethicists appeal to in their theories. Maybe this future sees a return to everyone appealing to common sense morality and ethical intuition, or maybe we simply find a way to avoid interactions that require ethical principles to govern them and go on to live in isolated bubbles where direct conflict becomes simply impossible.

Philosophers seek principles of justice that serve humanity’s interests. Yet this can also promote, or at least obscure, the interests of the privileged and powerful

I do not know how to assess the probability of either of these futures, but I believe that they would both be undesirable. Humanity’s inherent abilities to cooperate and to build economic and political institutions that facilitate trade, transfer ideas, and manage our violent instincts are far from perfect. But they have been essential for our efforts to start tackling global issues such as nuclear weapon proliferation or climate change.

However, this is a challenge that is only getting more and more difficult as global societies integrate, local communities fragment and stratify, technological and environmental change speeds up and the international challenges we face get harder and harder to solve. Ethics may have emerged in part as a response to the problem of repeated social collapse, but that problem is still with us, and its consequences are arguably greater than they have ever been.

Nor is this likely to get any easier. Several of the future trajectories that humanity might take imply a future where the intuitive and emotional processes by which we seek to diffuse violence and get along with one another become more or less redundant. These include “post-human” futures, in which we voluntarily give up these capacities as reflections of human biases and weaknesses, and futures in which we colonise space, making long-distance communication almost impossible due to the vast distances involved.

Ethical principles bind us as a society, and prevent a collapse into chaos (Credit: Getty Images)

Thus, I remain hopeful that we can make create a third future, building on the ethical approaches we have inherited towards universal principles that can both guide human behaviour and address the pressing challenges we face. Such a theory would have the attractiveness of ancient wisdom, the rigour of contemporary philosophy and the ability to engage with the complexity and uncertainty we face.

If that sounds utopian, I would point out that while the challenges facing ethics are in some ways getting harder, our tools for solving them – from our computational capacity to understand how humans interact with the world to our psychological understand our moral motivation – are growing as well.

Several philosophers have suggested that, should we manage to navigate our current period of global risk and uncertainty, humanity should take the time for a “long reflection” in which we deliberately slow down technological progress to give us time to better understand ourselves and our values before deciding what we want to do next. Achieving this would surely stack the odds in our favour.


Simon Beard is a researcher at the Centre for the Study of Existential Risk at the University of Cambridge, and a BBC Radio 3 New Generation Thinker. He tweets @simon_beard.

Join more than one million Future fans by liking us on Facebook, or follow us on Twitter or Instagram.

If you liked this story, sign up for the weekly bbc.com features newsletter, called “The Essential List”. A handpicked selection of stories from BBC Future, Culture, Capital, and Travel, delivered to your inbox every Friday. 

Around the bbc