When worldbuilding, what elements can be introduced that can justify the conquest or overtaking of a technologically superior species by one that is not as advanced, or much weaker.
Oh so many things, it's a great open ended question.
Answering assuming one nation is more technologically advanced and economically powerful than the other but is conquered by the less advanced one.
- Just because you have technology and money doesn't mean you are using it on your military
Different cultures focus different amounts of tech, wealth, effort on military power than others.
Given time nations can pivot their effort and improve their militaries, but this can take years. A sudden war from an inferior enemy can catch you without any standing army.
After WWI the US military shrunk to almost nothing. Even though the US had advanced tech, large population and lots of industrial capability it took years of lend-lease production and recruiting ramp up to get the US military on par with other powers when the second world war started.
- Some technology differences don't really impact combat
The difference between a soldier from the year 1200BC and a soldier from the year 800AD is not major. One has bronze, the other iron - maybe a 50% advantage but not a 10 to 1 advantage. At that point the ability to organize and motivate a larger army is more important.
- Desperation, and complacency
Many times in history we see a nation make changes when they are desperate and have to, and remain complacent whenever they have the chance. Japan retained its medieval technology level for hundreds of years but was forced out of isolationism at gunboat point. It then went though the almost miraculous Meji restoration modernizing a nation from the medieval era to a WWI era military capable of defeating a major power in 1 generation.
In the ashes of WWI the victors assumed the next war would be the same and rested on their laurels, they neglected understanding the new tactics which would come with tanks and airpower. The defeated nations (Germany and Russia) needed to improve so they experimented with new weapons and would have the edge in the coming war.
Nations that don't have to fight a war may resist making changes they have to make to fight a war, and may resist them for a long time.
Put it another way: fighting to the death means you might die, so you don't do that unless it's for something really important.
- Do the people care if they are conquered
There is a joke (I admit not a great joke) that China conquered an empire by being conquered. There are several Chinese dynasties that start with a neighboring warlord or tribe leader (with less advanced technology) invading and conquering China. The Chinese bureaucracy and government system was so good that the incoming warlord would just use it and become emperor in China as well as their home kingdom. Gradually the emperor's home kingdom is put under the same government system and is absorbed into China, and thus China grew.
It was bad for the former emperor and his soldiers but for the average peasant it mostly just changed who they were paying taxes to. Before the advent of nationalism in the 1800's most people were not that loyal to their country let alone being willing to die for it.
Maybe the citizens of "defeated" nation don't care about which emperor is in the palace, and just change the faces printed on the currency and absorb their conquerors.
Have you never heard of the barbaric invasions leading to the collapse of the Roman Empire?
The Romans were able to build structures like the Colosseum, the Pantheon and all the aqueducts to supply their cities with water, yet they were defeated by gents whose best building was a straw covered hut.
How did that happen? Weak central power for the amount of territory to control, economical crisis and some well timed plagues.
So many options
- High morale defeats low morale
- If your troops dont want to fight, they're not going to win. If the war is unpopular at home, and the troops are spat on as killers when they come home for a break, they're not going to be an effective fighting force. Think Vietnam war. Huge oversimplification but were the USA motivated on the home front at the same level as they were in ww2 Vietnam would be a us territory now. They werent motivated. Instead south Vietnam got overrun and captures.
- Weight of numbers
- A thousand guys with spears could take out a few guys with a super weapon. Look at the StarGate original movie final battle, as poor villagers rush Ras guards despite their superior staff ray guns.
- Element of surprise - or underestimating
- Look at tet offensive. A "primitive" vietnamese army launched a sophisticated attack on the us military. It was beginning of the end and ended up capturing Saigon.
- Supply lines
- When Germany invaded Soviet Union the tech balance was in favour of the germans. They stretched their supply lines and eventually starve and froze to death. 5 years later half of Germany is under Soviet occupation.
War and conquest, according to Von Clausewitz, is about politics. Political sophistication (or ossification) is not particularly correlated to technology.
War and conquest, according to Jomini, is about proper application of the principles of objective, offensive, mass, economy of force, maneuver, unity of command, security, surprise, and simplicity. Only four of those nine principles are markedly improved by technology.
You don't need superior technology to recruit allies, or to drive a political wedge to split the enemy alliance.
You don't need superior technology to coax the enemy to squander their strength and resources seizing objectives that turn out to be worthless.
You don't need superior technology to sow fear and terror in the enemy population, nor to bribe (or daunt) the enemy leaders.
Technologically Advanced is not the same things as Militarily Advanced
Because the OP mentions different species, not just different cultures
Humans for example have evolved through generation after generation of constant warfare to constantly think about and innovate new ways of killing. We invent a knife: we start making swords. We invent a firecracker: we start making guns. We split an atom: we start making nukes. Basically, if we invent something, it is in our nature to ask how we can turn that invention into a weapon. It only take a cursory glance at our entertainment industry to see that by the time a human child reaches adulthood, he's already experienced thousands of hours of simulated violence preparing him for real world conflicts.
But what if your advanced species does not think like us? Maybe they did not evolve on a world where war was a thing; so, while they know that their anti-matter reactors, and FTL drives are potentially dangerous, it's just not in their nature to ask themselves how to turn those things into weapons.
Now let's say that such an advanced species were to encounter a less advanced human like species, they would only be learning what a "gun" is for the first time when one start shooting them. They might try weaponizing their dangerous technologies, but the very idea of war is just so darn scary and repulsive to them that they can't find any of their own people willing to go to war... and when they do, they are so psychologically un-cut out for it that any armies they do assemble fall into chaos at the first signs of danger.
In the end, the advanced species can not figure out how fight a war, but they can figure out that if they just do what the violent species asks them to do, that they will stop killing them. This comes as a huge relief to them when they realize that being conquered is an option.
... but if both species are similarly warlike by nature
Even with more or less equal military instincts, their cultures may not put the same emphasis on military technology. This has happened a few times throughout history. One example was the conquest of the Western Roman Empire. The Germans were much less advanced than Romans when it came to architecture, agriculture, logistics, luxury goods, etc. But when it came down to the basics of things like weapons and armor, the Germanic peoples were constantly innovating in these areas; so, they often enjoyed the technological advantage on the battlefield, even if their civil technologies were not as good. So yes, Rome could generally be described as more advanced, but their aqueducts and amphitheaters could not protect them from being conquered by superior military technology.
As for when Military Technology is Inferior
This is a much more rare case, but it does happen. When one group of people are less militarily advanced, they can often resist being conquered using Guerrilla Warfare, but this does not really allow them to exert their control over another nation in most cases. Conquest means that you need to be present and accessible to rule which is the antithesis of Guerilla Warfare; so, when a technologically inferior army outright defeats a superior one it typically follows some combination of the following 3 models:
The inferior nation has superiority of numbers. The Battle of Isandlwana is a good example of this where the Zulu nation sent 20,000 men armed with stone-age weapons against about 1,800 British soldiers armed with rifles. The Zulu's numerical advantage was enough that they could close into melee range before the British could fire enough rounds to stop the charge. WWII is another good example. The most of the allies had distinctly inferior military technology to Germany, but between the Battle of the Bulge and Operation Barbarossa, the allies had about a 6-1 numerical advantage and conquered Nazi Germany.
The inferior nation is quick to adopt the technologies of those they fight. Rome was bad at innovating their own military technologies as I've already pointed out, but they were very good at recognizing and copying the military technologies of others. So, while there were many wars that started off looking very bad for Rome, the Romans would just adopt whatever weapons and strategies that they were losing to allowing their superior numbers and logistics to decide the final outcome of many of their conflicts.
The inferior nation chooses a battlefield or strategy which favors the technology that they do have. A good example of this would be the first Hebrew conquest of Israel. The native Philistines fought in the Mycenaean Greek tradition of Phalanxes armed with bronze scale or plate armor, long spears and heavy shields supported by a large number of chariots, while the Hebrews were mostly armed with wicker shields, no armor, and short weapons like clubs and Khopeshes after the Egyption military tradition and are believed to be lacking in chariots or mounted warriors in general. Although other wars showed without a doubt the superiority of phalanx infantry, and the value of mobility offered by chariots, the Hebrews were good at luring the Philistines into terrain that was too rough to maneuver a phalanx or chariots in, and were thus able to win a number of key battles and conquer "the promised land" despite significantly inferior military gear.
"Superiority" is a science fiction short story by British writer Arthur C. Clarke, first published in 1951. It depicts an arms race during an interstellar war. It shows the side which is more technologically advanced being defeated, despite its apparent superiority, because of its willingness to discard old technology without having fully perfected the new. Meanwhile, the enemy steadily built up a far larger arsenal of weapons that while more primitive were also more reliable.
I note that "conquer" is ambiguous. One culture can overrun another and even install a member of its culture as the monarch, without being able to hold onto it for a long time.
But the main way this works is social problems on the part of the conquered. They are many, not united, generally engaging in in-fighting. This means that the conquerors can take them piece by piece. Parts of the conquered may even surrender without fighting to avoid their culturally internal foes. Others may betray their foes to the conquerors because they think their position as conquered will be superior to their position pre-conquest. Many will regard the conquest of those of other factions/regions as not their problem.
This works for the initial conquest, but it does lead to the problem that it's hard to hold. The culture will not start working as a unified and harmonious whole merely because the other side won.
Sometimes people become so enamored with technologic advances that they forget the simpler ones even exist.
One Stargate SG1 antagonist was the Replicators, technological beings that could replicate themselves. The Asgard (a technologically advanced race with FTL travel and incredible weaponry), were struggling against them until the SG1 team brought their "primitive" weapons... basic military firearms. The bullets could shatter their bodies and were not electronic in any form. It proved to be devastating to them.
The technologically inferior people has a super seductive, infectious culture.
Your tech inferiors have the coolest clothes. The ladies do their hair in amazing ways. Their popular music makes you dance, then cry, then dance and cry. Their food is so delicious and addictive and their cultural icons croon to the Jungian archetypes in every soul. They have a religion that is so appealing it is no contest with what passed in the tech superior country for religion.
Yes they are barbarians, these inferiors. Their factories are inefficient and clunky. Their medicine is out of date. But they are so cool that everyone wants to have them around! Everyone wants to be like them. Their culture moves in, with their language right behind, hybridizing with the native language. Within a couple of generations, the citizens of the technologically superior nation are indistinguishable from those of the inferior nation. Does that count as "overtaking"?
One example I can think of is infectious American culture. Hellenism may be similar - the spread of Greek culture thru the ancient world not via conquest but because of the intrinsic appeal of that culture. Maybe @AlexP will weigh on the accuracy of that juxtaposition.
What you can do is have a large faction in the technologically inferior civilization request to join the more advance civilization and have the more advance civilization come to help this faction 'liberate' the country. The USSR justified many of their invasions this way since many of the nations they entered had a Communist Party that specifically requested the aid of the Soviet Union like how East Germany formed after the fall of the Nazi Germany during Soviet occupation, partly because the newly reformed German Communist Party asked for the USSR's continued aid in establishing a socialist republic. So similarly, have a major political party of the less technological nation request help from the more technological nation to build a more stable nation, making the situation less of an outright 'conquering', legally speaking, and more like assisting political allies.
what elements can be introduced that can justify the conquest or overtaking of a technologically superior species by one that is not as advance
Make the advanced species human and the less advanced a disease or parasite.
At all times in history humans have been more advanced than bacteria or mosquitoes and yet for thousands of years we had no technological way of fighting them.
There's a really good case study for this in the interactions between the various steppe cultures of northeastern Asia (Xiongnu, Göktürks, Mongols) and the Chinese dynasties to the south. The steppe peoples weren't primitive by any stretch of the imagination, but they did live a much more hand-to-mouth subsistence lifestyle that lacked a lot of the complex technology or social institutions that become more useful when a culture has a sedentary agrarian lifestyle. Nevertheless, the Chinese dynasties were constantly worried about their neighbors to the north and went to war with them and were actually conquered by them several times (the most famous example of which being Genghis Khan).
The more advanced culture isn't as militarized
China is rather notable among a lot of ancient culture for not having a strong warrior culture or elite warrior class. Rome had the legions, Japan had the samurai, the Greeks had the hoplites, the Aztecs had the various warrior cults, etc. The Chinese...didn't really have any of that. They had a very well-equipped army, but China post-warring states period was a largely Confucian society that valued education, harmony, and learning rather than who can stab whom in the face the best. The ideal Chinese man was seen to be a scholar first, rather than a soldier or a warrior. The Chinese had more advanced weapons in a lot of ways, including repeater crossbows, gunpowder, and complex trebuchets, but they weren't a heavily militarized power with a strong warrior culture that encouraged constant warfare.
By contrast, the steppe cultures were heavily militarized. The different tribes were frequently at war with another, and virtually every aspect of steppe life could be translated into warfare in some way. The steppe peoples were good horseback riders, practiced archery in their daily lives for hunting, and even many sports such as jereed or buzkashi have a role in training horsemanship skills that translate well into warfare. Just about every able-bodied steppe man was able to serve as a soldier, and with the greater experience many steppe warlords had from the harsher lifestyle on the plains were able to translate that into greater tactics and gain a strategic advantage over the larger, but less experienced, Chinese armies.
The less advanced culture outperforms the more advanced one in some way
In terms of technology, the steppe people really only had one thing over the Chinese, their horsemanship, but the thing is they were really, really good at it. China has always had problems with its horses, to the point that one of the few major Chinese expeditions outside China was to obtain better horses that could be ridden rather than restricted to pulling chariots. The steppe peoples were much better riders, which gave them better mobility on the battlefield and allowed them to win many engagements despite being armed with compound bows in contrast to Chinese crossbows. The Chinese really couldn't dictate terms of engagement to the steppe peoples, couldn't really invade their territory (every time they tried the nomads just ran further into the Gobi), and if they broke formation it resulted in the nomads pulling their army apart and winning. In this case being a specialist worked better than being a generalist.
Even if your more technologically advanced culture on average has greater technology, the less advanced one might still outperform them in some area because not every culture develops technology in the same way or the same rate.
The less advanced culture is able to capture weapons from their more technologically advanced enemies and turn them back on them
One of the way the Mongols were able to finally bring down the Jin and Song dynasties were through the adoption of siege warfare techniques such as trebuchets and battering rams. These were mostly designed by Muslim and Chinese engineered captured in west Xia and parts of Jin, not by the Mongols themselves. There isn't a lot of a need to be hauling a catapult around on the Mongolian plains. The Mongols were actually really bad at siege warfare at first, in the first siege of Yinchuan they were completely unable to break through the walls of the city and resorted to trying to divert the Yellow River in an attempt to flood the city, only for it to backfire when the river flooded the Mongol camp. By the end of the war against the Jin they were adept with using siege equipment to the point they were able to crack open even heavily fortified cities.
It should be relatively easy for a less advanced group to get their hands on the technology of the more advanced group, through asymmetrical warfare if nothing else. Though, depending on how much of a tech gap there is there might be issues with manufacturing enough to supply all of your troops. For example Native Americans often had issues with getting firearms, especially as they lacked the industrial base to build more guns and ammunition.
Ultimately, though, your less advanced culture is going to have to adopt new weapons or upgrade their old ones. Human wave tactics may work in the short term but in the long term you're trading your most plentiful resource (soldiers) away in a bad bargain for better odds. Eventually the high casualty rate will become a problem.
The more advanced culture is in political disunity or civil war
This is a common trend in history. An empire is in some kind of decline or internal conflict and the resulting disunity allows outside groups to tear it apart. In this case Rome, rather than China, would be the premier example, where neglect of the armies, mismanagement of the economy, overexpansion, and politicians who were more focused on backstabbing each other than preserving the empire (among many other reasons) allowed for outside people to run havoc and carve out their own empires in places like Thrace and the northern Sahara. One big factor that caused problems was that Roman propaganda (and history, since Romans heavily censored their own history) framed non-Romans as backwards idiots, which often led to the Romans thinking the barbarians weren't a threat or weren't politically savvy until it was too late.
It's incredibly what people can do with faith. Vikings for example, they didn't have any fear to die in battle because of their faith in their gods knowing that they would go to Valhalla if they die in battle and feast with the gods. In other hands, some other civilization without faith would be afraid of fighting and dying and leaving family and friends behind.
Also, in a war scenario, if you don't have faith in your Commander's plan, then you would probably not be the best soldier you could be if you had faith in the plan.
Therefore, a less advanced species with more faith could fight better than the advanced species without any faith.
As a relatively extreme example, consider the Great Emu War. It was fought between soldiers from a top-notch army armed with the latest machine gun technology, and a bunch of flightless birds the size of a mid-size deer. What sounds like it should be a one-sided massacre ended up being an overwhelming failure. The emus were able to render the advanced weapons nearly useless by staying out of range, forcing the attackers to chase them at high speeds over rough terrain (making aiming impossible), splitting into smaller groups (minimizing the number of targets available), and using their agility to make target tracking difficult.
This was done by what are frequently referred to as one of the least intelligent birds on the planet. They certainly had no concept of war, weapons, or tactics. Yet they were still able to exploit the weaknesses of the "superior" attacker and to force the attacker to fight on their terms. If the emus had become angry enough to counterattack, their vastly superior numbers would likely spell doom for the army regiment (emus have sharp claws and a powerful kick that can kill a human).
Other examples include the Battle of Endor, the Martian invasion in The War of the Worlds, or even the Battle of the Little Bighorn. The common theme is that the technologically-inferior side controls the battle. Local knowledge, brute force, and targeted attacks at the enemy's weak points are the keys to victory. Avoiding or marginalizing their fancy high-tech weaponry is important if you want to live long enough to win.
Every weapon has a weakness. It doesn't matter how high tech you are, war is always about turning your strengths against the enemy's weaknesses. As long as your technologically-inferior group is strategy-minded and can dictate the terms of battle, they can overwhelm and defeat a "superior" foe.
I'd be very wary of looking to fiction for answers to this, since the stories often rely on a heavy swathe of "plot armour" to make sure the results play out the way the author intended. And equally, there's no shortage of military sci-fi (e.g. most of Baen's output) where technological imbalances lead to the more primitive army being fed into a meat grinder.
(Though to be fair to David Weber in particular, for all that he's fond of this concept, he does also sometimes look at ways for the "underdog" to compensate...)
Fundamentally though, there's a few key factors when a primitive society takes on an advanced society.
The first is that an advanced society will generally be allocating more of it's resources to non-military activities. Which includes the percentage of it's population which can be made available for war.
The second is that advanced technology - and the training to use it - is expensive.
The third is that it depends on the size of the technology delta.
The fourth is that (at least in my distinctly amateur opinion), primitive societies can be more willing to risk more, take more dramatic actions and absorb losses. Not least because from a resourcing perspective, the cost of replacing their soldiers is far less than the cost for the advanced society.
E.g. it probably costs around $45,000 to get a single US marine trained, equipped and ready to hit the field. And that's before you consider the cost of the logistics required to get said marine to where he needs to be, with the equipment he needs to carry out his orders. And that's still a tiny fraction of how much it costs to train a tank driver or a fighter pilot - or to deliver them and their vehicles to battle.
When all is said and done, technology is essentially a force multiplier. To use a non-military example, one diesel tractor in a field is maybe worth the equivalent of 100 men when it comes to ploughing, etc. But it's probably only worth the equivalent of maybe 4 steam-powered tractors.
And in either case, a mechanical tractor costs significantly more, both initially and ongoing. And unlike those 100 men, it can only do a specific set of tasks, it can only be in one place at a time and it requires a lot more maintenance, which needs to be done by skilled mechanics. Who need to have been trained beforehand.
Sometimes, the force-multiplier can be high enough to make a difference. Rourke's Drift, where 150 british soldiers fought off several thousand Zulu warriors; a significant factor was that the zulu warriors perceived firearms as a "coward's weapon" and therefore preferred hand-to-hand combat.
On the other hand, consider what can happen if the technology delta is smaller, and the "primitive" society is willing to absorb large losses. Because that's essentially what happened with Nazi Germany's assault on Russia (with some assistence from the harsh russian weather).
In fact, look at what could happen today if some country decided to equip an army with WW2-era hardware.
E.g. the M4 Sherman tank cost approx. $900,000 in 2017 dollars. An M1 Abrams would cost around $9 million, or ten times more.
A P40 Warhawk plane would also cost around $900,000 in 2017 dollars, whereas a modern F-35A is somewhere around $80 million, or nearly a hundred times more.
And as with the tractor, that's before you consider the time and cost needed to train people to use this newer and far more complex hardware.
Then too, your expensive F-35A plane would be able to blow those 100 P40 planes out of the sky, but it can't be everywhere at once. And an M4 Sherman tank would be more than capable of dealing with local armed forces, militia and police forces, especially if embedded with some well trained infantry. Ten of them would pose a major challenge to that Abrams tank; they might struggle to kill it outright, but they'd be able to encircle it and immobilise it.
Because by not fighting, the Ancients win.
The Barbarians win - that's fine. Now they have, at their beck and call the robot army of Ancients, caring for their every whim. It's a useless army if you want to fight a war - but evey Barbarian now lives a life of comfort and ease that they've never imagined prior. Why to to war if you've got everything you want?
The Ancients weren't, actually, to be honest, the driving force of the Old Empire. For milenia they were a trap. A target for the younger, hungry races to watch and envy. And each time someone attacked... the attackers won! Only to be cared for, pampered, pacified...turned into pets.
Pets of the sentient robot army built to look after, at first, the Anchents. Then ever poor squishy mortal race who attacked. They were just not able to care for themselves - or wise enough to avoid the trap the Ancients fell into themselves.
If a technologically inferior culture can re-think it's view of the opposing technology, it can see that all machines need to "breath", and hence can be choked. All machines need to see, and therefore can be blinded. etc. If the so-called inferiors can see the fundamentals of what they are looking at, then they can create strategies to defeat them. Imagine shoving a 6 foot piece of rebar down a tanks barrel!
The advanced species isn't prepared for the war really is. I'm thinking of a theme I've seen more than once in stories:
Interstellar travel is a slow business, it takes decades to make a voyage. The advanced species is relying on very old scouting reports. The advanced species has been united under a single world government with something akin to a command economy for a long, long time--their technological progress is now very slow. (Think of China--they thought they were way superior, change was a threat to those in power so they stagnated until they got a very rude awakening--picture that attitude on a planetary scale.)
Their scouts have reported a planet at say middle ages tech and 500 years later they go decide to add it as a conquest. They bring weapons suitable for utterly overwhelming such an opponent. As they intend conquest rather than destruction they don't bring more than a few city-killer weapons--they're for shock and awe, not actual combat. They actually run into something like modern-day Earth:
The ground forces are along the lines of APCs/light tanks and are total sitting ducks when the Hellfires come in from no apparent enemy. (The Hellfire was originally meant to be guided in by a helicopter hiding behind terrain and only sticking up a targeting pod that is mounted above the rotors, the actual shooters being completely behind terrain and shooting where they were directed to.)
They are air-mobile--but knights can't harm aircraft, they only have transport aircraft and they have no defenses at all. If the missile booster has burned out they will have no idea it's coming until it hits and they are built like civilian craft--no attempt to minimize battle damage.
They are not carrying the supplies to turn around and head home with their metaphorical tails between their legs. Their only choices become suicide or surrender.
To make it even harder on them they might be using some sort of non-inertial drive--the power to cross the stars is not the power to move large rocks so kinetic bombardment isn't an option. (Note that I do not mean only something like the intertialess drive of the Lensman series. Warp drives partially fall into this category. The drive used in the Starfire series (David Weber/Steve White) also come to mind.)
Well, you could do something like in War of The Worlds, towards the end of it, all the Martians died out because they got infected with human diseases, like the flu and the common cold. Essentially what happened when the American Settlers came into contact with Native Americans. Their immune systems were not ready to fight of a incredibly infectious and deadly disease.