Why Aliens Wouldn’t Be Hostile

Many people think we should avoid contacting aliens because they’ll be hostile to us. I hear this everywhere, from folks in my roleplaying group all the way up to geniuses like Stephen Hawking.

For the moment, this is a purely theoretical question. If there isn’t intelligent life in our corner of the universe, then it won’t matter if we think contact is a good idea. But it’s entirely plausible that we might receive a signal someday, and it’s disheartening that so many people think we shouldn’t answer. We have every reason to think aliens would be peaceful.

Reaching the Stars Requires a Peaceful Society

When discussing what aliens would or wouldn’t be like, we have little choice but to use humanity as a model. Flawed as this approach is, it’s the only one we’ve got right now. From looking at humanity’s bloody history, many have assumed aliens would be inherently violent. This position is understandable; humans often do terrible things to each other, and we have plenty of evidence that competition is needed for advancement.

But if we assume that aliens will follow a similar path to humans, that actually makes them less likely to be violent. Violence among humans has been on a steady decline for at least a century, both in war and at the individual level. That may not feel true from watching the news, which seems more violent every day, but that’s an issue of reporting bias. We’re getting better at reporting violence, and so it seems like there’s more. At the same time, headlines about violence are more attention grabbing than headlines about people living peacefully. This is probably why Americans are afraid of terrorism but not traffic accidents.

The reasons for our decline in violence are myriad, but a major factor has been the increase in our destructive capability. As our weapons become more and more powerful, war stops being a valid option for material gain, because whatever you’re trying to get will be destroyed in the process. Humans have barely dipped a toe into space, but we’ve already reached a point where most of our powerful nations simply cannot risk going to war with each other.*

Aliens capable of reaching us would be far more powerful. They might not all be fun-loving party animals, but they would never have survived to leave their solar system if they didn’t know how to solve problems without violence. It’ll be interesting to see if we humans are capable of making that leap.

All Resources on Earth Exist Elsewhere

Another common fear is that aliens would want to crush us, not because sapient creatures are inherently warlike, but because the aliens will want our stuff. This fear also seems reasonable at first glance. Most conflicts in human history have been about resources, with moral justifications added afterwards. Aliens could easily do the same thing.

Or they would, if there was anything remotely special about Earth. This might be a blow to our human egos, but nearly anything found on our planet can be found elsewhere. Iron, water, diamonds, the list goes on. Extra terrestrial bodies are teaming with resources, many of them much easier to extract than what we have here. Our synthetic materials are even less likely to interest spacefaring aliens, for the same reason modern humans aren’t in a hurry to replace their smart phones with telegraph stations.

Even if a hypothetical race of aliens were so into mega-projects that they managed to use up the resources in their home system, there are countless star systems in our galaxy alone that don’t have a human infestation. Unless the aliens are coming from Alpha Centauri, it would be far easier to visit an uninhabited system than to come here.

Think about it: if you were presented with two soda cans, one of them covered in ants, you’d take the one without ants right? You could brush the ants off, but why bother when there’s an ant-free can right in front of you?

Crossing Space Means You Can Live in Space

While none of the Earth’s resources are unique in the cosmos, or even rare, there is one quality that makes our planet special: it supports life. It’s the only planet we know of that does. So maybe aliens would want to conquer our planet so they can have more living space for their growing population? That’s certainly the plot of more than a few scifi stories.

This concern requires that any aliens we meet can actually live on Earth, but that’s certainly plausible. For all we know, only planets with conditions similar to ours can support life. Even if the aliens can’t live here, Earth might be more like their homeworld than lifeless bodies like Venus or Mars,* and so it would be easier to terraform.

That sounds pretty grim, until we consider that before any aliens try to move in next door, they have to get here. If they can travel quickly between the stars, that means they have faster than light (FTL) technology. Modern physicists are divided about whether FTL is possible at all, but if it is, it will require energy expenditures on a level that is difficult for humans to conceptualize. Any civilization advanced enough to produce those levels of energy could just live in space.

Space habitats aren’t that hard to build. We can make them right now, it’s just expensive to send so much mass into orbit. If we could harness the energy needed to travel faster than light, we’d be building Dyson Spheres in a second. FTL capable aliens would have so much orbital real estate, the idea of flying all the way to Earth would be laughable.

Alternatively, aliens might take the slow way, crossing the interstellar void in huge generation ships. That’s an unwieldy way to launch an invasion, but it’s possible. But if they can survive for centuries in space, what reason do they even have to land on Earth? They’ve clearly mastered the art of living in the vacuum, even without the god-like technology of FTL.

We’d Be Terrible Slaves

There’s one thing we know for sure that only Earth has: humans.* Perhaps inspired by the human predilection for enslaving each other, some people think aliens would see humans themselves as a resource. Isn’t that a good reason to be scared of aliens? No one wants to get sent to the spice mines of Kessel after all.*

I’m afraid that once again, I must chip away at our sense of specialness. You see, humans just aren’t that good at working, at least not compared to robots. We’re close to automating all human labor ourselves, and that’s with puny homo-sapien tech. Compared to sleek, sexy robots, we humans are weak, fragile little monkeys that require constant food and access to toilets just to stay alive. Plus, any alien who kept a stable of humans would have to deal with constant escape attempts. Not worth the effort.

Then we get into the more exotic uses for humans. Maybe the aliens are mind-worms who need a host body to live. Or maybe they’ve just developed a taste for our succulent livers.* Either option is possible, anything’s possible with aliens, but why bother coming all the way to Earth when hungry aliens could grow their own humans at home?

In recent years, we’ve taken huge steps in the development of artificial wombs. It’s likely that some time soon, we’ll be able to create humans in a laboratory, no pregnancy required. Spacefaring aliens are almost certain to have far superior biotech, and any human-related needs could easily be satiated at home. Certainly it would be easier than crossing the vast distances to Earth.

Aliens Would Know We’re No Threat

A final reason people often give to support fear of aliens is the idea that they would want to preemptively destroy us. Better to take us out now while we’re helpless than risk humans growing in power to rival them. That certainly sounds like a reason to be afraid. If aliens decided to launch a preemptive strike, there’s little we could do.

Except everything I’ve been saying about aliens applies to humans too. By the time we’re able to travel the stars, we’ll no longer have any need for conquest. Advanced aliens would figure that out. They’d have no reason to launch a first strike. They’d know that in time, humans will either self-destruct or figure out our problems and become less terrible.

Assuming aliens would launch a first strike is a paradox. It requires that aliens be intelligent enough to build interstellar weapons, but not intelligent enough to realize humans are no threat to them. We should give ET a little more credit.

I can’t say with absolute certainty that aliens wouldn’t be hostile. No one can say anything about aliens with absolute certainty. The universe is a strange and wondrous place, and clever scifi writers are very good at finding unlikely edge cases to make their evil aliens seem realistic. But by the same token, I can’t be absolutely certain that the grocery store clerk won’t stab me next time I buy food. I go anyway, because the benefits far outweigh the risks. The same is true for aliens. Just finding out that we aren’t alone would completely change how we view the universe. And imagine if they decided to tell us stuff. Technology that seems trivial to advanced aliens could completely revolutionize life on Earth. We need to get over our fears now, so that we don’t miss the opportunity, if it ever comes.

(Psst! If you liked my article, check out my magical mystery game.)

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  1. SunlessNick

    Unless the aliens are coming from Alpha Centauri, it would be far easier to visit an uninhabited system than to come here.

    And even then, it would be easier to mine asteroids, comets, and the moons of gas giants than Earth.

    For all we know, only planets with conditions similar to ours can support life.

    There are good reasons to think so, at least when it comes to life as complex as ours.

    But if they can survive for centuries in space, what reason do they even have to land on Earth?

    By the time they get here – especially if it is a journey of literal generations for them – living on a planet may seem positively weird to them. The novel Footfall referred to this (though it didn’t explore it in a *lot* of depth) – the invaders came in a ship that was mostly sleeper, but with a small generational crew to maintain it – but by the time it reached Earth, the latter didn’t care about invading it at all, and only went along with it because they were outranked.

    Spacefaring aliens are almost certain to have far superior biotech, and any human-related needs could easily be satiated at home.

    From a technological standpoint, yes, though understanding of human biology is likely to be the one thing we have a good chance of being better at than them – cf one of the common tropes of benevolent aliens offering us awesome medicines rather than, say, awesome battery technology. On the other hand, it’s hard to imagine a human-related not that’s not better met by something that evolved on the same planet as them.

    Aliens Would Know We’re No Threat

    There’s a brief arc in Farscape where the characters find their way to Earth, and Aeryn Sun (a soldier from an interstellar power) is interviewed on TV about the danger of alien invasion.
    And her thesis was essentially that neither Earth nor humanity offers anything anyone don’t already have, and Earth is too primitive to be regarded as a threat or worth cultivating as an ally. So *could* any of the various galactic powers destroy or enslave humanity? Yeah. But it’s not worth it.

    (The talking heads really didn’t appreciate her perspective).

    • Michael

      On the last, in a perverse way it makes us feel important to think aliens would invade Earth. Aren’t we special?

  2. Cay Reet

    This reminds me a little of the ‘we are space Australia’ thing on Tumblr.

  3. Thane Bonnett

    I agree that peace is the most stable and likely situation. As you said in your article on empires, modern civilization has learned that it is cheaper and easier to purchase resources than to seize them.
    However, for peace to end wouldn’t require everyone to suddenly forget the lessons of history. It might only require a single rouge actor.
    “The Parable of the Tribes” explores how in a system of peaceful actors, aggression on the part of a single rouge actor can force all peaceful actors to take steps to prepare for conflict; inducing a positive feedback cycle of suspicion and hostility: “force can only resisted with greater force.” .

    This is how the European peace established at the Congress of Vienna eventually eroded, and it all blew up as the result of nonstate rouge actors and poor communication among mutually suspicious states.

  4. American Charioteer

    Before WWI, military planners believed that the next war would be won by whoever mobilized the fastest. Thus, even mobilizing was seen as akin to an act of war, and something as benign as building railroads was a threatening action. Unfortunately, this may parallel the situation that would exist between alien actors, as the technology that processes resources for peaceful purposes will look identical to technology that processes resources to produce war material. The biggest step of mobilization (recruiting soldiers) can be entirely skipped if wars are fought by unmanned craft, and so any expansion may be seen as military expansion.

    Cixin Liu’s “The Dark Forest” trilogy explores this exact idea; proposing that aliens live in constant fear of each other because they never know who will experience an unexpected leap of technology and decide to become a rouge actor.

  5. American Charioteer

    Interestingly, Harary’s proof shows that in any in a system of actors that contains aggression; every Nash Equillibrium state (state where no one can unilaterally improve their position) is a division of the actors into exactly two factions. (This video provides an excellent explanation: ). This is a rather intuitive result and explains why stable tripolar systems of states or wars with three groups of combatants are rare. Though it doesn’t preclude an equilibrium with no hostility at all, again we see that only a single rouge actor is required to disrupt the equilibrium.
    A powerful alien civilization is likely to know this and thus may attack weak civilizations preemptively to prevent them from allying or sharing technology.

  6. Deus Ex Anthropos

    If a single actor disrupted the zero-hostility Nash Equillibrium state, wouldn’t the others states unite to stop it? The two factions would be all-previously-peaceful-states vs the single rogue player.

    • Thane Bonnett

      In a human system, yes. In fact, that is the point of international law and international organizations: to serve as a force of negative feedback in the zero-hostility equilibrium state.

      However, this requires pre-existing friendly relations between all actors (to get to the zero-hostility state in the first place), and that requires both communication and cultural understanding. Both of those things are difficult from lightyears away, between beings who may have completely different biology and psychology.

      • American Charioteer

        Oh, you reminded me of something: laser light meant to interfere with communication or cause direct damage travels through space at the exact same speed as laser light used to communicate. The cosmic speed limit puts us back in the days when messengers couldn’t move much faster than armies.

        • Deus Ex Anthropos

          I guess the existence of lasers and the fragility of our ecosystem makes flying saucers a bit ridiculous.

          • American Charioteer

            If you mean that combat in space would likely mostly occur from extremely long distances with lasers and AI-guided missiles, then I agree. It also means that space dogfights would be boring to watch.

  7. JXMcKie

    You forgot the most important argument for alien hostility…they would want to carry away our womenfolk, so the alien scum must be taught a lesson by the muscle-bulging hero with his trusted blaster Joking aside, yes it is really bad news for dramatic Space-Opera´s, (but good news in the real world) that it is so difficult, to find a logical reason for conflict between teoretical alien civilzations and us. As a Sci-fi author, one has to cook up some good explanation for such a conflict. That being said, it doesn´t mean conflict is totally unthinkable…some of the better explanations are presented in Babylon 5 two “elder” species, Vorlons and Shadows, using their younger “client” species to settle a philosophical arguments, by slugging it out. Or even more scarry : The Reapers from the Mass Effect trilogy ! The endings might divide fans of Mass Effect and there is certainly a problem with logic of those endings, but the premise of the Reapers cyclic annihilation of all highly developed sentient life, was perhaps not so farfetched after all…
    …and let´s hope that it is not the case, but conflict makes for more dramatic story !

  8. actualethere

    “No one can say anything about aliens with absolute certainty.”

    I can say this with absolute certainty. Both hostile, benevolent and ambivalent ET civilizations exist and have been interacting with Earth and or Earth humans from the get-go.

    Additionally, the variety of species hang on a spectrum of what we would call ESP and communicate telepathically. Some are powerfully psychic and some seemingly not at all. Add this spectrum crossing the “benevolent-malevolent” axis and things start to get interesting, if also confusing.

    here is an important question: Are earth humans benevolent? or malevolent?

    The answer should stop short with some obvious needs for clarification, definition of terms and a epistemological “conversation about the conversation. ”

    The answer, as almost always, is “it depends”.

    Even when benevolent, we know what the road to hell is paved with and sometimes a summer feast can lead to famine if birthrates exceeds a species ability to remain sustainable.

    likewise malevolent intentions or negative circumstances can produce unexpected consequences that turn out to be positive or strengthening.

    all that said, we don’t make terrible slaves and in spite of use of clones as biological machines, often times humans are used as technicians, inventors, engineers, ect throughout the galaxy.

    AI machines, as Frank Herbert and others suggest, turn to be more problematic than anything.

    So are we a threat? Well, the small but powerfully equipped minority that exists in compartmentalized secret space programs certainly can be seen that way, depending on the ET civilization that is looking at us.

    Some would see a threat, others not. Depends on how you define “we” when these compartmentalized top-tiers of the deep-state aren’t exactly regular, rolly-polly humans we would define the term.

    At some point the breakaway civilization is the fork in a bifurcation of a species and our definitions of who We are start to get fuzzy.

    Could earth humans themselves be an “alien threat”?

    anyway, your conception of what ET life is like, what they would or wouldn’t do/make/say/think is restricted by the aperture of your worldview, to say nothing of your level of consciousness. It doesn’t matter how smart you are, if your frame of reference is being manipulated and crucial information is being withheld, you won’t see much beyond what you are allowed.

    A tiny peephole into a titanic hall, full of dangerous treasures and their guardians.

    To open that worldview that has been artificially narrowed, forget anon comments in a fiction thread and go listen to NASA astronauts speak about the issue. They are fairly plainspoken about what they know regarding intelligent non-human life interacting with earth and their people.

    The truth is not “out there” it’s right here. Buried just beneath your fear of looking like a fool.

  9. carl

    ‘violence has been declining for at least a hundred years’

    A quarter million years of history, and a 100 years of peace- that includes two world wars. That doesn’t seem like good data to use in projecting a trend. I actually buy most of the logic in that section entirely. While isolated to this planet, it makes no sense to engage in destructive behavior that would destroy anything worth fighting over. But how many nuclear powers have committed troops to wars since WWII? I”m guessing it’s a large percentage of the total number, and I know the US and Britain, and France, ect ect have done so multiple times.

    In short, the restraint required for survival doesn’t seem to requires anything resembling perfect peace.

    • Cay Reet

      Day to day violence might have decreased over time, the more our society (whichever one that might be) frowns on it and punishes it. As a species, we will always be violent, because we’re omnivores and prepared to hunt and kill to survive. The question is which outlets we have. War with our neighbours is an outlet. So is a football match. So is a violent video game. So is a violent movie. All those other outlets than war allow us to project our aggression on something or someone and get rid of it. Watching an execution in the middle ages was just as much an outlet as really hitting or killing someone.

      Wars are not fought for violence as a such, they are fought because at least one side wants something and at least one side doesn’t want to give that something up. It might be influence, it might be land, it might be a person (Helena of Troy, anyone?). Wars are the last tool in the toolbox of diplomacy and always were and always will be.

  10. Guy Srinivasan

    > When discussing what aliens would or wouldn’t be like, we have little choice but to use humanity as a model. Flawed as this approach is, it’s the only one we’ve got right now.

    This is not just false but obviously false. Also, a very dangerous mistake. Good thing geniuses like Hawking aren’t making it!

    • Oren Ashkenazi

      For the record, Hawking specifically uses the parallel of Europeans and Native Americans to make his point about why humans shouldn’t contact aliens.

    • Guy Srinivasan

      To clarify: I do not object to using humanity as a model. I object to saying it’s the only approach we have, and even worse drawing conclusions from the premise “somehow I know there is only one way to approach this problem”.

  11. Deana

    Sorry, but your premise is flawed from the get go. Violence at the Intersocietal level has never been greater than in the last 125 years. Just a very incomplete list will demonstrate the fallacy of comparing intrasocietal declines in violence to international and intercultural increases. Boer War (first use of concentration camps), World War 1 (including Armenian Genocide), Ukrainians Famine/Genocide, World War 2, Korean War, Vietnam, the Killing Fields, Guatemala, Nicaragua, Rwanda, Eritrea, South Sudan, East Timur, South Africa, Nigeria, Iran-Iraq War, Somalia, Gulf1,Balkans, Gulf 2, Afghanistan, the Rohingya, and that is just a representative list. Since 1850 there has been a major war, usually including genocide, or religiocide, somewhere on the planet, every day. Violence is not decreasing. Our lack of empathy with the other has.

    • Cay Reet

      It is impossible to list all wars in Europe during the middle ages, because quite some were over in a battle or two and because there were too many. As far as religiocide goes, have you heard about the early inquisition? When they were only going for herectics and before they went for witches? Or about the witch hunts? Genocide has happened in the past as well, in more cases than we know of for sure these days, because we have no traces left of them.

      It’s not known how many wars were fought in both Americas, because all written data the Native Americans in north and south might have had were destroyed or are simply no longer readable, because the knowledge of the languages used has been destroyed. Not to mention the cultures and their spoken memory have been destroyed – by the European conquerors starting around 1490 AD. Same goes for Africa, another continent ‘conquered’ by the supposed ‘better’ races and used up for resources long before the last 125 years.

      Wars have happened among humans for a long time, but modern times have heightened the amount of deaths in a single war, due to the weapons used (especially all kinds of weapons of mass destruction). We do not know whether concentration camps of a sort have been used in ancient times, because we have no reports of them. That doesn’t mean they didn’t exist. As a matter of fact, knowing humans, it’s quite likely members of a people someone was at war with were most likely locked away (concentration camp style) or outright killed.

      And if you think modern humans are less emphatic than those who thought a different skin colour meant you could kill and torture others at will… Slavery is still around today and it’s important not to forget or ignore that, but it was going on at much higher rates in the past. And it was considered much more normal. In most countries of this planet (yes, even in Europe and North America), slavery today happens in the underworld, in criminal surroundings. They call it trafficking, but it’s the same thing. However, you can’t just walk onto a marketplace and compare the twenty female slaves on sale for their uses in your household or on your fields, as if they were working horses. If you ask me, that’s actually a big step forward for our empathy with other humans outside of our society.

      Humans have always been aggressive, but that doesn’t necessarily mean alien races are as well. Given we are too much at each other’s throats to actually get some kind of manned space travel beyond the reach of our own moon going, I dare say no alien race as aggressive as us will have had a decent chance at mastering space travel, either, before they destroyed themselves. That means any race which has has either never had that level of aggression or they have learned to control/conquer it. In both cases, they would not come as conquerors.

  12. Mitchell McDonald


    It is overwhelmingly likely that an alien species that can travel the stars AS A WHOLE would be fairly peaceful if not at least neutral to any primitive species they may meet (namely us)…


    If a group of alien CRIMINALS or aliens with vastly different morals or goals than their species as a whole were to get lost and land or crash on Earth or come here on purpose for some reason, who knows what their intentions for us might be? Wonder if they are low on supplies from running away from alien authorities or the crash destroyed most of their means of survival?

    Plus, wonder if the aliens that landed WERE peaceful BUT they crashed or ran out of supplies on their way here? They probably wouldn’t be any threat to humanity as a whole or WISH any harm to us, but if they were DESPERATE ENOUGH I would sure not want to test if they would or wouldn’t value THEIR SURVIVAL over a “primitive” human family in a house nearby with plenty of food and supplies for the taking, especially if some of them are hurt or some humans see the crash and attack the aliens out of fear. Consider this: If you survived a plane crash out in the middle of the wild and saw a pack of animals with a hoard of food they were protecting or if they attacked you, would you think twice about killing them for you or others’ survival?

    • Oren Ashkenazi

      Editor’s note: I’ve removed a small section of this comment to avoid unfortunate racial implications. The rest of the comment is fine, but I urge everyone to consider the possible meanings when comparing real humans to hypothetical aliens.

      • Mitchell McDonald

        I simply was using the unfortunate constant terror attacks and danger in the area of the Middle East as a comparison to the rest of the world as an example that although we may be a very peaceful race as a whole, there are people out there who are anything but. The majority of people in the Middle East aren’t violent, let me make that clear.

    • Mitchell McDonald

      ALSO, wonder if the alien society’s technology gets so advanced that a space travelling vessel capable of reaching our planet becomes as cheap as a used car and practically ANY OF THEM (criminals, individuals or groups with more sinister morals than the majority, or an inexperienced or lost alien (think teenage driver)) can easily land or crash here with little effort?

      • Cay Reet

        I dare say that’s unlikely. Distances in space are huge and even if the vessel were relatively cheap, there would be a lot of fuel of whatever kind needed to get to us. It would basically be as if you drove your car from east to west coast (or the other way around) just for a bagel. Some might consider that, but it would still be expensive and would probably take rather long. There are probably more interesting worlds to crash on closer to those aliens.

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