Many EA ideas do not require a particular moral theory. However, much EA moral thinking leans consequentialist (i.e. morality is fundamentally about consequences), and often specifically utilitarian (i.e. wellbeing and/or preference fulfilment are the consequences we care about). This is for good reason.

Utilitarian morality can be thought of as rigorous humanism, where by “humanism” I mean the general post-Enlightenment secular value system that emphasises caring about people, rather than upholding, say, religious rules or the honour of nations. Assume that the welfare of a conscious mind matters. Assume that our moral system should be impartial: that wellbeing/preferences should count the same regardless of who has them, and also in the sense of being indifferent of who’s perspective it is being wielded from (for example, a moral system that says to only value yourself would give you different advice than it gives me). The simplest conclusion you can draw from these assumptions is to consider welfare to be good and seek to increase it.

I will largely ignore differences between the different types of utilitarianism. Examples of divisions within utilitarianism include preference vs hedonic/classical utilitarianism (do we care about the total satisfied preferences, or the total wellbeing; how different are these?) and act vs rule utilitarianism (is the right act the one with the greatest good as its consequence, or the one that conforms to a rule which produces the greatest good as its consequences – and, once again, are they different?).

Utilitarianism is decisive

We want to do things that are “good”, so we have to define what we mean by it. But once we’ve done this, this concept of good is of no help unless it lets us make decisions on how to act. I will refer to the general property of a moral system being capable of making non-paradoxical decisions as decisiveness.

Decisiveness can fail if a moral system leads to contradiction. Imagine a deontological system with the rules “do not lie” and “do not take actions that result in someone dying”. Now consider the classic thought experiment of what such a deontologist would do if the Gestapo knocked on their door and asked if they’re hiding any Jews. A tangle of absolute rules almost ensures the existence of some case where they cannot all be satisfied, or where following them strictly will cause immense harm.

Decisiveness fails if our system allows circular preferences, since then you cannot make a consistent choice. Imagine you follow a moral system that says volunteering at a soup kitchen is better than helping old people across the street, collecting money for charity is better than soup kitchen volunteering, and helping old people across the street is better than collecting money. You arrive at the soup kitchen and decide to immediately walk out to go collect money. You stop collecting money to help an old person across the street. Halfway through, you abandon them and run off back to the soup kitchen.

Decisiveness fails if there are tradeoffs our system cannot make. Imagine highway engineers deciding whether to bulldoze an important forest ecosystem or a historical monument considered sacred. If your moral system cannot weigh environment against historical artefacts (and economic growth, and the time of commuters, and …), it is not decisive.

So for any two choices, a decisive moral system must be able to compare them, and the comparisons it makes cannot be circular preference. This implies a ranking: X is better than Y translates to X is before Y in the ranking list.

(If we allow circular preferences, we obviously can’t make a list, since the graph of “better-than” relations would include cycles. If there are tradeoffs we can’t make – X and Y such that X and Y are neither better than equal or worse than each other – we can generate a ranking list but not a unique one (in set theory terms, we have a partial order rather than a total order).)

Decisiveness also fails if our system can’t handle numbers. It is better to be happy for two minutes than one minute than fifty nine seconds. More generally, to practically any good we can either add or subtract a bit: one more happy thought, one less bit of pain.

Therefore a decisive moral system must rank all possible choices (or actions or world states or whatever), with no circular preferences, and with arbitrarily many notches between each ranking. It sounds like what we need is numbers: if we can assign a number to choices, then there must exist a non-circular ranking (you can always sort numbers), and there’s no problem with handling the quantitativeness of many moral questions.

There can’t be one axis to measure the value of pleasure, one to measure meaning, and another for art. Or there can – but at the most basic level of moral decision-making, we must be able to project everything onto the same scale, or else we’re doomed to have important moral questions where we can only shrug our shoulders. This leads to the idea of all moral questions being decidable by comparing how the alternatives measure up in terms of “utility”, the abstract unit of the basic value axis.

You might say that requiring this extreme level of decisiveness may sometimes be necessary in practice, but it’s not what morality is about; perhaps moral philosophy should concern itself with high-minded philosophical debates over the nature of goodness, not ranking the preferability of everything. Alright, have it your way. But since being able to rank tricky “ought”-questions is still important, we’ll make a new word for this discipline: fnergality. You can replace “morality” or “ethics” with “fnergality” in the previous argument and in the rest of this post, and the points will still stand.

What is utility?

So far, we have argued that a helpful moral system is decisive, and that this implies it needs a single utility scale for weighing all options.

I have not specified what utility is. Without this definition, utilitarianism is not decisive at all.

How you define utility will depend on which version of utilitarianism you endorse. The basic theme across all versions of utilitarianism is that utility is assigned without prejudice against arbitrary factors (like location, appearance, or being someone other than the one who is assigning utilities), and is related to ideas of welfare and preference.

A hedonic utilitarian might define the utility of a state of the world as total wellbeing minus total suffering across all sentient minds. A preference utilitarian might ascribe utility to each instance of a sentient mind having a preference fulfilled or denied, depending on the weight of the preference (not being killed is likely a deeper wish than hearing a funny joke), and the sentience of the preferrer (a human’s preference is generally more important than a cat’s). Both would likely want to maximise the total utility that exists over the entire future.

These definitions leave a lot of questions unanswered. For example, take the hedonic utilitarian definition. What is wellbeing? What is suffering? Exactly how many wellbeing units are being experienced per second by a particular jogger blissfully running through the early morning fog?

The fact that we can’t answer “4.7, ±0.5 depending on how runny their nose is” doesn’t mean utilitarianism is useless. First, we might say that an answer exists in principle, even if we can’t figure it out. For example, a hedonic utilitarian might say that there is some way to calculate the net wellbeing experienced by any sentient mind. Maybe it requires knowing every detail of their brain activity, or a complete theory of what consciousness is. But – critically – these are factual questions, not moral ones. There would be moral judgements involved in specifying exactly how to carry out this calculation, or how to interpret the theory of consciousness. There would also be disagreements, in the same way that preference and hedonic utilitarians disagree today (and it is a bad idea to specify one Ultimate Goodness Function and declare morality solved forever). But in theory and given enough knowledge, a hedonic utilitarian theory could be made precise.

Second, even if we can only approximate utilities, doing so is still an important part of difficult real-world decision-making.

For example, Quality- and Disability-Adjusted Life Years (QALYs and DALYs) try to put a number on the value of a year of life with some disease burden. Obviously it is not an easy judgement to make (usually the judgement is made by having a lot of people answer carefully designed questions on a survey), and the results are far more imprecise than the 3-significant-figure numbers in the table on page 17 here would suggest. However, the principle that we should ask people and do studies to try figure out how much they’re suffering, and then make the decisions that reduce suffering the most across all people, seems like the most fair and just way to make medical decisions.

Using QALYs may seem coldly numerical, but if you care about reducing suffering, not just as a lofty abstract statement but as a practical goal, you will care about every second. It can also be hard to accept QALY-based judgements, especially if they prefer others to people close to you. However, taking an impartial moral view, it is hard not to accept that the greatest good is better than a lesser good that includes you.

(Using opposition to QALYs as an example, Robin Hanson argues with his characteristic bluntness that people favour discretion over mathematical precision in their systems and principles “as a way to promote an informal favoritism from which they expect to benefit”. In addition to the ease of sounding just and wise while repeating vague platitudes, this may be a reason why the decisiveness and precision of utilitarianism become disadvantages on the PR side of things.)

Morality is everywhere

By achieving decisiveness, utilitarianism makes every choice a moral one.

One possible understanding of morality is that it splits actions into three planes. There are rules for what to do (“remember the sabbath day”). There are rules for what not to do (“thou shalt not kill, and if thy doest, thy goeth to hell”). And then there’s the earthly realm, of questions like whether to have sausages for dinner, which – thankfully – morality, god, and your local preacher have nothing to say about.

Utilitarianism says sausages are a moral issue. Not a very important one, true, but the happiness you get from eating them, your preferences one way or the other, and the increased risk of heart attack thirty years from now, can all be weighed under the same principles that determine how much effort we should spend on avoiding nuclear war. This is not an overreach: a moral theory is a way to answer “ought”-questions, and a good one should cover all of them.

This leads to a key strength of utilitarianism: it scales, and this matters, especially when you want to apply ethics to big uncertain things. But first, a slight detour.

Demandingness

A common objection to utilitarianism is that it is too demanding.

First of all, I find this funny. Which principle of meta-ethics is it, exactly, that guarantees your moral obligations won’t take more than the equivalent of a Sunday afternoon each week?

However, I can also see why consequentialist ethics can seem daunting. For someone who is used to thinking of ethics in terms of specific duties that must always be carried out, a theory that paints everything with some amount of moral importance and defines good in terms of maximising something vague and complicated can seem like too much of a burden. (I think this is behind the misinterpretation that utilitarianism says you have a duty to calculate that each action you take is the best one possible, which is neither utilitarian nor an effective way to achieve anything.)

Utilitarianism is a consequentialist moral theory. Demands and duties are not part of it. It settles for simply defining what is good.

(As it should. The definition is logically separate from the implications and the implementation. Good systems, concepts, and theories are generally narrow.)

Scaling ethics to the sea

There are many moral questions that are, in practice, settled. All else being equal, it is good to be kind, have fun, and help the needy.

To make an extended metaphor: we can imagine that there is an island of settled moral questions; ones that no one except psychopaths or philosophy professors would think to question.

This island of settled moral questions provides a useful test for moral systems. A moral system that doesn’t advocate kindness deserves to go in the rubbish. But though there is important intellectual work to be done in figuring out exactly what grounds this island (the geological layers it rests on, if you will), the real problem of morality in our world is how we extrapolate from this island to the surrounding sea.

In the shallows near the island you have all kinds of conventional dilemmas – for example, consider our highway engineers in the previous example weighing nature against art against economy. Go far enough in any direction and you will encounter all sorts of perverse thought experiment monsters dreamt up by philosophers, which try to tear apart your moral intuitions with analytically sharp claws and teeth.

You might think we can keep to the shallows. That is not an option. We increasingly need to make moral decisions about weird things, due to the increasing strangeness of the world: complex institutions, new technologies, and the sheer scale of there being over seven billion people around.

A moral system based on rules for everyday things is like a constant-sized knife: fine for cutting up big fish (should I murder someone?), but clumsy at dealing with very small fish (what to have for dinner?), and often powerless against gargantuan eldritch leviathans from the deep (existential risk? mind uploading? insect welfare?).

Utilitarianism scales both across sizes of questions and across different kinds of situations. This is because it isn’t based on rules, but on a concept (preference/wellbeing) that manages to turn up whenever there are morally important questions. This gives us something to aim for, no matter how big or small. It also makes us value preference/wellbeing wherever it turns up, whether in people we don’t like, the mind of a cow, or in aliens.

Utilitarianism and other kinds of ethics

Utilitarianism, and consequentialist ethics more broadly, lacks one property that is a common social (if not philosophical) use of morality.

Consider confronting a thief robbing a jewellery store. A deontological argument is “stealing is wrong; don’t do it”. A utilitarian argument would need to spell out the harms: “don’t steal, because you will cause suffering to the owner of the shop”. But the thief may well reply: “yes, but the wellbeing I gain from distributing the proceeds to my family is greater, so my act is right”. And now you’d have to point out that the costs to the shop workers who will lose their jobs if the shop goes bankrupt, plus more indirect costs like the effect on people’s trust in others or feelings of safety, outweigh these benefits – if they even do. Meanwhile the thief makes their escape.

By making moral questions depend heavily on facts about the world, utilitarianism does not admit smackdown moral arguments (you can always be wrong about the facts, after all). This is a feature, not a bug. Putting people in their place is sometimes a necessary task (as in the case of law enforcement), but in general it is the province of social status games, not morality.

Of course, nations need laws and people need principles. The insight of utilitarianism is that, important as these things are, their rightness is not axiomatic. There is a notion of good, founded on the reality of minds doing well and fulfilling their wishes, that cuts deeper than any arbitrary rule can. It is an uncomfortable thought that there are cases where you should break any absolute moral rule. But would it be better if there were rules for which we had to sacrifice anything?

Recall the example of the Gestapo asking if you’re hiding Jews in your house. Given an extreme enough case, whether or not a moral rule (e.g. “don’t lie”) should be followed does depend on the effects of an action.

At first glance, while utilitarianism captures the importance of happiness, selflessness, and impartiality, it doesn’t say anything about many other common moral topics. We talk about human rights, but consequentialism admits no rights. We talk about good people and bad people, but utilitarianism judges only consequences, not the people who bring them about. In utilitarian morality, good intentions alone count for nothing.

First, remember that utilitarianism is a set of axioms about the most fundamental definition of good is. Just like simple mathematical axioms can lead to incredible complexity and depth, if you follow utilitarian reasoning down to daily life, you get a lot of subtlety and complexity, including a lot of common-sense ethics.

For example, knowledge has no intrinsic value in utilitarianism. But having an accurate picture of what the world is like is so important for judging what is good that, in practice, you can basically regard accurate knowledge as a moral end in itself. (I think that unless you never intend to be responsible for others or take actions that significantly affect other people, when deciding whether to consider something true you should care only about its literal truth value, and not at all about whether it will make you feel good to believe it.)

To take another example: integrity, in the sense of being honest and keeping commitments, clearly matters. This is not obvious if you look at the core ideas of utilitarianism, in the same way that the Chinese Remainder Theorem is not obvious if you look at the axioms of arithmetic. That doesn’t somehow make it un-utilitarian; for some examples of arguments, see here.

See also this article for ideas on why strictly following rules can make sense even for strict consequentialists, given only the fact that human brains are fallible in predictable ways.

As a metaphor, consider scientists. They are (in some idealised hypothetical world) committed only to the pursuit of truth: they care about nothing except the extent to which their theories precisely explain the world. But the pursuit of this goal in the real world will be complicated, and involve things – say, wild conjectures, or following hunches – that might even seem to go against the end goal. In the same way, real-world utilitarianism is not a cartoon caricature of endlessly calculating consequences and compromising principles for “the greater good”, but instead a reminder of what really matters in the end: the wishes and wellbeing of minds. Rights, duties, justice, fairness, knowledge, and integrity are not the most basic elements of (utilitarian) morality, but that doesn’t make them unimportant.

Utilitarianism is horrible

Utilitarianism may have countless arguments on its side, but one fact remains: it can be pretty horrible.

Many thought experiments show this. The most famous is the trolley problem, where the utilitarian answer requires diverting a trolley from a track containing 5 people to one containing only a single person (an alternative telling is doctors killing a random patient to get the organs to save five others). Another is the mere addition paradox, also known as the repugnant conclusion: we should consider a few people living very good lives as a worse situation than many people living mediocre lives.

Of course, the real world is never as stark as philosophers’ thought experiments. But a moral system should still give an answer – the right one – to every moral dilemma.

Many alternatives to utilitarianism seem to fail at this step; they are not decisive. It is always easier to wallow in platitudes than to make a difficult choice.

If a moral system gives an answer we find intuitively unappealing, we need to either reject the moral system, or reject our intuitions. The latter is obviously dangerous: get carried away by abstract morals, and you might find yourself denying common-sense morals (the island in the previous metaphor). However, particularly when dealing with things that are big or weird, we should expect our moral intuitions to occasionally fail.

As an example, I think the repugnant conclusion is correct: for any quantity of people living extremely happy lives, there is some larger quantity of people living mediocre lives that would be a better state for the world to be in.

First, rejecting the repugnant conclusion means rejecting total utilitarianism: the principle that you sum up individual utilities to get total utility (for example, you might average utilities instead). Rejecting total utilitarianism implies weird things, like the additional moral worth of someone’s life depending on how many people are already in the world. Why should a happy life in a world with ten billion people be worth less than one in a world with a thousand people?

Alternatives also bring up their own issues. To take a simple example, if you value average happiness instead, eliminating everyone who is less happy than the average is a good idea (in the limit, every world of more than one person should be reduced to a world of one person).

Finally, there is a specific bias that explains why the repugnant conclusion seems so repugnant. Humans tend to show scope neglect. If our brains were built differently, and assigned due weight to the greater quantity of life in the “repugnant” choice, I think we’d find it the intuitive one.

However, population ethics is both notoriously tricky and a fairly new discipline, so there is always the chance there exists a better alternative population axiology than totalism.

Is utilitarianism complete and correct?

I’m not sure what evidence or reasoning would let us say that a moral system is complete and correct.

I do think the basic elements of utilitarianism are fairly solid. First, I showed above how requiring decisiveness leads to most of the utilitarian character of the theory (quantitativeness, the idea of utility). The reasons are similar to the ones for using expected value reasoning: if you don’t, you either can’t make some decisions, or introduce cases where you make stupid ones. Second, ideas of impartiality and universality seem like fundamental moral ideas. I’d be surprised if you could build a consistent, decisive, and humane moral theory without the ideas of quantified utility and impartiality.

Though this skeleton may be solid, the real mess lies with defining utility.

Do we care about preferences or wellbeing? It seems that if we define either in a broad enough way to be reasonable, the ideas start to converge. Is this a sign that we’re on the right track because the two main variants of utilitarianism talk about a similar thing, or that we’re on the wrong track and neither concept means much at all?

Wellbeing as pleasure leaves out most of what people actually value. Sometimes people prefer to feel sadness; we have to include this. How? Notice the word I used – “prefer”. It seems like this broad-enough “wellbeing” concept might just mean “what people prefer”. But try defining the idea of preference. Ideal preferences should be sincere and based on perfect information – after all, if you hear information that changes your preference, it’s your estimate of the consequences that changed, not the morally right action. So when we talk about preference, we need complete information, which means trying to answer the question “given perfect information about what you will experience (or even the entire state of the universe, depending on what preferences count) in option A and in option B, which do you prefer?” Now how is this judgement made? Might there be something – wellbeing, call it – which is what a preferrer always prefers?

Capturing any wellbeing/preference concept is difficult. Some things are very simple: a healthy life is preferable to death, for example, and given the remaining horribleness in the real world (e.g. sixty million people dying each year) a lot of our important moral decisions are about the simple cases. Even the problem of assigning QALY values to disease burdens has proven tractable, if not easy or uncontroversial. But solving the biggest problems is only the start.

An important empirical fact about human values is that they’re complex. Any simple utopia is a dystopia. Maybe the simplest way to construct a dystopia is to imagine a utopia and remove one subtle thing we care about (e.g. variety, choice, or challenge).

On one hand, we have strong theoretical reasons why we need to reduce everything to utilities to make moral decisions. On the other, we have the empirical fact that what counts as utility to people is very complex and subtle.

I think the basic framework of utilitarian ideas gives us a method, in the way that the ruler and compass gave the Greeks a method to begin toying with maths. Thinking quantitatively about how all minds everywhere are doing is probably a good way to start our species’ serious exploration of weird and/or big moral questions. However, modern utilitarianism may be an approximation, like Newton’s theory of gravity (except with a lot more ambiguity in its definitions), and the equivalent of general relativity may be centuries away. It also seems certain that most of the richness of the topic still eludes us.

Indirect arguments: what people think, and the history of ethics

In addition to the theoretical arguments above, we can try to weigh utilitarianism indirectly.

First, we can see what people think (we are talking about morality after all – if everyone hates it, that’s cause for concern). On one hand, out of friends with who I’ve talked about these topics with (the median example being an undergraduate STEM student), basically everyone favours some form of utilitarianism. On the other hand, a survey of almost a thousand philosophers found only a quarter accepting or leaning towards consequentialist ethics (slightly lower than the number of deontologists, and less than the largest group of a third of respondents who chose “other”). (However, two thirds endorse the utilitarian choice in the trolley problem, compared to only 8% saying not to switch (the rest were undecided).) My assumption is that a poll of everyone would find a significant majority against utilitarianism, but I think this would be largely because of the negative connotations of the word.

Second, we can look at history. A large part of what we consider moral progress can be summarised as a move to more utilitarian morality.

I am not an expert in the history of ethics (though I’d very much like to hear from one), but the general trend from rule- and duty-based historical morality to welfare-oriented modern morality seems clear. Consider perhaps the standard argument in favour of gay marriage: it’s good for some people and it hurts no one, so why not? Arguments do not get much more utilitarian. (Though of course, other arguments can be made with different starting points, for example a natural right to various freedoms.) In contrast the common counter-argument – that it violates the law of nature or god or at least social convention – is rooted in decidedly non-utilitarian principles. Whereas previously social disapproval was a sufficient reason to deny people happiness, today we assume a heavy, even insurmountable, burden of proof of any custom or rule that increases suffering on net.

A second trend in moral attitudes is often summarised as an “expanding moral circle”: granting moral significance to more and more entities. The view that only particular people of particular races, genders, or nationalities count as moral patients has come to be seen as wrong, and the expansion of moral patienthood to non-humans is already underway.

A concern for anything capable of experiencing welfare is built into utilitarianism. Utilitarianism also ensures that this process will not blow up to absurdities: rather than blindly granting rights to every ant, utilitarianism allows for the fact that the welfare of some entities deserves greater weight, and assures us there’s no need to worry about rocks.

It would be a mistake to say that our moral progress has been driven by explicit utilitarianism. Abolitionists, feminists, and civil rights activists had diverse moral philosophies, and the deontological language of rights and duties has played a big role. But consider carefully why today we value the rights and duties that we do, rather than those of past eras, and I think you’ll find that the most concise way to summarise the difference is that we place more value on welfare and preferences. In short, we are more utilitarian.

Two of the great utilitarian philosophers were Jeremy Bentham and John Stuart Mill, who died in the early and late 1800s respectively (today we have Peter Singer). On the basis of his utilitarian ethics, Bentham advocated for the abolition of slavery and capital punishment, gender equality, decriminalising homosexuality (an essay so radical at its time that it went unpublished for over a hundred years after Bentham’s death), and is especially known as one of the first defenders of animal rights. Mill also argued against slavery, and is especially known as an early advocate of women’s rights. Both were also important all-around liberals.

Nineteenth century utilitarians were good at holding moral views that were ahead of their time. I would not be surprised if the same were true today.