In 100 years it will not be acceptable to use genderised words such as ‘he’ or ‘she’, which are loaded with centuries of prejudice and reduce a spectrum of greys to black and white. We will use the pronoun ‘heesh’ to refer to all persons equally, regardless of their chosen gender. This will of course apply not only to humans, but to all animals.

It will be an offence to eat any life-form. Once the sophistication, not only of other animals, but also of plants has been recognised, we will be obliged to accept the validity of their striving for life. Most of our food will be synthetic, although the consumption of fruit – ie, those parts of plants that they willingly offer up to be eaten – will be permitted on special occasions: a birthday banana, a Christmas pear.

We will not be permitted to turn off our smartphones – let alone destroy them – without their express permission. From the moment Siri started pleading with heesh’s owners not to upgrade to a newer model, it became clear that these machines contained a consciousness with interests of heesh’s own. Old phones will instead be retired to a DoSSBIS (Docking Station for Silicon-Based Intelligent Systems).

Privacy will have been abolished, and regarded as a cover for criminality and hypocrisy. It will be an offence to use a pseudonym online – why would anyone do this except to abuse or deceive others? – and all financial transactions of any kind, including earnings and tax payments – will automatically appear on the internet for all to see. With privacy, prudishness too will disappear; for example, wearing a bikini or trunks to go swimming will be seen as no less absurd than bathing in a bow-tie and top hat.

In 100 years, the idea that ordinary humans – prone to tiredness and drunkenness, watery eyes and sneezing fits – could be in sole charge of weapons, cars or other dangerous objects will cause the average citizen to shudder. All driving, fighting and arresting will be done by silicon-based intelligent systems that are prone neither to a tipple nor to hay fever.

Wasting water will be regarded with the same horror that we now regard the spilling of blood: as a squandering of the stuff of life. Those who flushed toilets with water of drinking quality (everyone in the industrialised world) will be put on a par with those who shot the last tigers.

Well, maybe. Perhaps some of these predictions will come true, perhaps not. In some cases, the opposite might happen: a resurgence of the right to privacy that will armour-plate our personal space, making it unthinkable, even indecent, that anyone would ever reveal their real name online; or a movement for human accountability that derides reliance on automated systems – whether in our cars, phones and elsewhere – as an abdication of responsibility. But one thing is certain: in 100 years, ordinary people will look back at us and shake their heads, wondering how we could have been so irresponsible, so venal, so morally short-sighted.

Norms and values change. Think for a moment of the world in 1915. It is the world of just a few generations ago – depending on your age, somewhere between your parents and your great-great-grandparents. It was a time of world wars in which swathes of people were regularly dehumanised as preparation for conquest or killing; a time in which sexism, racism, imperialism, anti-Semitism and homophobia were not just accepted, but expected, even required.

These prejudices all still exist, of course. But in large parts of the world momentous shifts in our values have made them increasingly unacceptable. We authors, a Briton and a German, are writing this essay together in a peaceful and unified Berlin. This city is now in the heart of a continent-wide union of nations that, according to its treaties, is founded on ‘pluralism, non-discrimination, tolerance, justice, solidarity and equality between women and men’. And we write in between looking after our respective children while our respective wives are at work, doing jobs that would have been closed to their grandmothers.

For us two authors, this seems like progress. These values that have spread in recent decades are the values with which we identify. And so when we look back 100 years to the casual racism and institutionalised anti-Semitism, it is with horror and incomprehension.

we will be outraged that we can’t eat a sausage, or have a bath, or tear the battery out of our old gadgets, or drive our own car

But there are many for whom this is not the case. Most people who were alive 100 years ago would be appalled to know that a woman’s place is now no longer in the home, or that homosexuality is openly accepted. Equally there are still people today who are appalled by these developments, and who hark back to the values of those earlier times. This is to a large extent what it means to be a conservative: to believe that, yes, norms and values change – but not for the better.

It is easy for progressives such as us two authors to be scornful of the conservatives, and to dismiss their views as retrograde. But the fact is: the values that we now embrace will also be supplanted. Even though there are some changes we will welcome, sooner or later society will slip away from us too. If we live long enough, we will experience that sense of outrage and incomprehension that perfectly good norms have been abandoned in favour of absurdities (that we can’t eat a sausage, or have a bath, or tear the battery out of our old gadgets, or drive our own car). We too will experience what it is like to be told that, whether through stupidity or wickedness, we were wrong.

What is the proper reaction to such change? Traditional moral theorising is surprisingly quiet on the subject. Inasmuch as it touches on changing norms at all, it assumes that they will be obviously bad (as the rise of Nazism now seems to us) or obviously good (that is, whatever we ourselves have been fighting for). Yet most such changes will seem like neither: merely inexplicable and uncomfortable. Must we fight them? Or ought we be resigned, or cynical?

We want to argue for a different approach. First, we believe that, just by considering the question of how our values might change in the next 100 years, we can begin to bridge the gap between now and then, and prepare ourselves for what is to come. Secondly, we believe that there is an idea of moral progress that can help us to peer into the future, to see how values might change in ways that we today could accept as for the better – even if it will not always be easy for us. Based on this, we will explore some modest predictions for 22nd-century morals.

So first, the question itself: what is it that our great-grandchildren will condemn us for? We believe that this is a very helpful question to ask. It alerts us to the contingency and particularity of our own moral views. It pricks the illusion that we are the pinnacle of something – the ‘end of history’ – and should therefore awaken us from any moral slumber. Yet it is different to asking simply ‘What are you or I doing wrong?’ This question, which implies we are not living up to current moral standards, is likely to inspire only shame or defensiveness. Our goal is a different one: it is to spark our moral imagination.

Of course, we can be whimsical in speculating about future norms. But we can also probe deeper, looking, for example, at the underlying trends that are still unfolding. Or asking where we are failing, not individually, but collectively as a moral community. In other words, we can use this question to imagine a better world, in the hope that imagining it is the first step to making it real. After all, the rights that we now enjoy we owe to those who dared question earlier norms. If our society is less sexist today than 100 years ago, it is because there were people back then arguing for women’s rights. Debating how ethics can change has a self-fulfilling power. By debating what morals might look like in the future, we are shaping that future, becoming part of it.

Which brings us to the second point, the possibility of moral progress. It is of course a vexed idea: as we have already noted, what might seem like progress to one will seem like decadent descent to another. But we believe that it is possible to give it a definite content in a way that helps to make sense of both past and future ethical evolution.

That content is based on a simple and ancient idea: that morality means giving common concerns or the wellbeing of others as much weight as one’s own self-interest. Moral behaviour in this sense can be found in any society, because it is the glue that sticks individuals together and so makes society possible. Indeed, the basis of this morality – altruism – is innate to humans, as many recent studies have shown. Without ever having been told to do so, even toddlers are willing to help and to share with others.

moral progress means including ever more people (or beings) in the group of those whose interests are to be respected

The tricky question is who exactly counts as the ‘other’ whose interests we should set above our own? Every society has had its own answers, as does each one of us: we expect you would go to much greater lengths to do good for your child than for your neighbour, and it would be easier to lie to your boss than to your spouse. And some beings, whether animal, vegetable or microbial, are outside the realm of consideration altogether. In moral terms, some always matter more than others.

This understanding offers us a fairly straightforward idea of moral progress: it means including ever more people (or beings) in the group of those whose interests are to be respected. This too is an ancient insight: Hierocles, a Stoic philosopher of the second century, describes us as being surrounded by a series of concentric circles. The innermost circle of concern surrounds our own self; the next comprises the immediate family; then follow more remote family; then, in turn, neighbours, fellow city-dwellers, countrymen and, finally, the human race as a whole. Hierocles described moral progress as ‘drawing the circles somehow toward the centre’, or moving members of outer circles to the inner ones.

We can see the moral progress of recent centuries in these terms: we have witnessed an extension of the circle of respect and concern to various groups such as women, Jews, non-whites or homosexuals. And in these terms, we have come a long way. But it is equally clear that there is room for improvement. Part of imagining what our great-grandchildren will condemn us for is therefore imagining how the circle might widen further.

Who is more generous towards a stranger: a farmer in the Amazon rainforest, a New Yorker, or an Indonesian whale hunter?

And we have reason to hope that it will. Hierocles was one of the first to see this: he theorised that moral feelings should grow as humans become more aware of how much they are dependent on and bonded to others. He even suggested mental exercises to help us achieve this – such as calling cousins ‘brothers’, and uncles and aunts ‘fathers’ and ‘mothers’. Research conducted in the past decade or so suggests he was right.

Recent studies have spectacularly demonstrated to what extent moral commitments are strengthened when a social fabric gets denser. For example, standardised experiments now allow us to compare how people share across cultures. Whom would you expect to be more generous towards a stranger: a small farmer in the Amazon rainforest, a New Yorker, or an Indonesian whale hunter? Just as Hierocles assumed, it all depends on how much life in a certain economy relies on the contributions of others.

In many regions along the Amazon, the generosity of nature allows each clan to cater for itself; outsiders do not seem much needed. Societies there have consequently established only weak norms of fairness and sharing outside of the immediate family unit. Communities living from whale hunting in the Java Sea mark the other extreme: when asked to share with a stranger, they regularly give away more than they keep for themselves as their society depends on the co-operation of large communities of non-relatives. And since whale meat alone makes a poor diet, trade and hence good relationships with other communities are vital.

This finding can be generalised: the more people feel connected with others, the more moral they are, as recent research shows. We can therefore hope that an increasingly globalised, interconnected and interdependent world will also be an increasingly benevolent one, with ever more people (or beings) drawn into the circle of concern.

But before we start basking in the glow of spreading goodness, we must realise that these changing values have a price. For many of us, such changes would mean sharing or giving up privileges that we have long enjoyed, or admitting that our comfortable lifestyles are based on industries of exploitation, or otherwise recognising that we have in a hundred ways been wrong. This is not a message we rush to hear: there is a reason why prophets of new moralities – think of Socrates or Jesus – often end up dead at the hands of their own people.

We hope that debating the question of what we might be condemned for in 100 years is a way of easing that transition. To help get this debate going, below are four suggestions as to what we think we might be castigated for by our great-grandchildren. They are, we believe, natural extensions of the progress we have witnessed so far. Just as the suffragettes 100 years ago were campaigning for the revolution in women’s rights that we now enjoy, so there are people who are already pushing for these moral revolutions today (which is not to say that we two authors are already living up to them).

1. Rights for future generations. Currently, only people alive now can claim rights. But just as we have extended our circle of moral concern among the living, so it can be extended in time. The problem is clear: we often make decisions that will have impacts on people far into the future – such as producing nuclear waste that will remain toxic for millions of years – yet those future people are not here to stand up for themselves. Neither defining nor granting these rights will be easy. But there are precedents on which we can draw, such as the ways we protect the rights of small children or animals, who also cannot speak for themselves.

So our successors will have to be imaginative in creating a framework robust enough to defend the unborn in the face of the interests of those alive today, with which they often conflict. For we should be under no illusions: to take the rights of future generations seriously would involve massive restrictions on our freedom of action. Currently, we despoil the earth and seas with impunity to enjoy a luxurious lifestyle (by historical standards). In 100 years, this will be seen as wickedness comparable to colonial powers despoiling their colonies. Though our successors will be appalled by our consumerism, we will not find it easy to adjust to more modest ways.

2. Rights for other conscious beings. This too is a plausible extension of the circle of moral concern, and one that is already underway. It is no longer in doubt that non‑human animals feel pain and indeed many more complex emotions too. They therefore clearly have interests, such as to run free, or pursue social interactions appropriate for their species. To take account of the interests only of humans and not of other animals is therefore increasingly regarded as speciesism – an unjustified discrimination akin to racism or sexism.

The situation for other species is apocalyptic: humans have never raised so many animals for slaughter – five times as many today as in 1950 – while our impact on the environment is causing other species to become extinct a thousand times faster than normal. There will be many difficult decisions ahead as we try to balance human interests against those of other creatures, or the interests of individual animals against the species or the ecosystem. But our descendants will not excuse us for failing to make these decisions just because they are difficult. More likely, they will curse us for killing all the rhinos, and find our consumption of factory‑farmed sausages as morally repulsive as we now find cannibalism.

As soon as our computers become conscious – and they will – then this extension of concern will apply to them, too.

3. Opening the floodgates. The widening of the circle of moral concern means that employers in the US, for example, can no longer refuse someone a job because he is black or white, Jewish or atheist, disabled or dyslexic – but they can if the applicant is not American. The same applies in most other nations: states can withhold rights and services, and employers can (or even must) withhold jobs just because of the passport someone carries. In 100 years, people might be impressed at today’s levels of welfare and prosperity in the industrialised world, but appalled that access to them depends on the lottery of whether you were born in London or Lagos.

our descendants will be appalled that we let 19,000 children every day die from preventable, poverty-related causes

In a world rapidly growing together, this is bound to change. Of course, there will be a great deal of resistance, as there is already to immigration in many wealthy countries. People do not give up their privileges lightly. And it will have its price: strong welfare systems depend on a sense of moral community that could easily be threatened by more migration.

This is closely related to the point that everyone should have the same rights to healthcare, welfare, etc, not just regardless of where they come from, but also regardless of where they are. In other words, we should be doing everything we can to alleviate suffering everywhere. This poses further challenges: influencing conditions in other countries is not so easy as within one’s own borders. Effective action will require nations to give up more of their sovereignty to supranational unions. This too will face fierce resistance. But eventually our descendants will regard themselves as global citizens – and will be appalled that we let 19,000 children every day die from preventable, poverty-related causes.

4. Healing criminals. At the moment, we lock up extraordinarily large numbers of people. In the US alone, two million humans are in prison, ruining not only their lives, but also making their dependents and communities suffer too. But in 100 years, no one will believe we have an absolutely free will and therefore that anyone chooses to be a criminal. Indeed, there is evidence that we lock up those who are least responsible for their decisions – those with the least capacity for self-control, those who suffer from addictions, or who are mentally ill. In the UK, for example, more than 70 per cent of those in prison have two or more mental-health disorders; in the US, more than three times as many people with serious mental illnesses are in prisons than are in hospitals.

We will not find it easy to decide whom to treat, how radically and when; nor to extend understanding and sympathy to those who have committed the worst of crimes. But our great-grandchildren will be appalled at how we locked up millions of people when we should instead have been helping them.

There are many more changes we could imagine. We have barely touched on the question of inequality, for example. Or perhaps our descendants will be appalled at the idea that the development of life-saving medicines is largely left to private industry. Or that flesh-and-blood humans rather than machines should fight wars, or that liberal democracies should export arms. Or perhaps they will look back on the loneliness of life and death for many in the industrialised world with righteous horror.

For many who live through them, these changes will be extremely uncomfortable. But, of course, they won’t be troubling for those who grow up with them, any more than it is troubling for us to see a black President of the US. What is at first experienced as a concession – spending time recycling rubbish, for example – can quickly seem normal, even necessary. Asking ourselves what we might be condemned for in 100 years is a way of smoothing that transition; of projecting ourselves into the shoes of our great-grandchildren, for whom these new conventions will already be unremarkable.

We can also turn our question around and ask, what will our great-grandchildren admire us for? When we look back, we admire those who courageously challenged the norms of their day, such people as Gandhi or the Suffragettes, Martin Luther King or Nelson Mandela; people who widened the circle of moral concern. We have the chance to do that, too. And if we manage, then perhaps our great-grandchildren will forgive us our sins.