Worldbuilding Stack Exchange is a question and answer site for writers/artists using science, geography and culture to construct imaginary worlds and settings. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

In the world I'm working on, magic has been Sufficiently Analyzed, and has been turned into a well-defined science. It takes the place of much of technology (why invent the forklift, when a magically-augmented human is just as strong, and far more agile?). It does, however, have two limitations:

  1. It can only be cast on a willing subject. You can't cast a spell on an inanimate object, and animals that can be trained to accept spells are rare.
  2. It's subject to conservation of energy.

Given those limitations, which would you use for heavy physical labor (eg. pulling a plow or a freight wagon): an augmented human, or a horse? The human is at least as strong as the horse, so which has a greater capacity to do work?

share|improve this question
Regarding #2 - where does the energy come from? If you enchant a human to be able to lift 10 tons does he have to eat a huge feast beforehand or something? – colmde Jan 5 at 10:33
This blog post might be relevant: Cost of Maintaining a Horse in Regency London – Ilmari Karonen Jan 5 at 10:41
@colmde, a single 10-ton lift from the ground to an upper shelf is only about 50 kcal. It's extended periods of effort that require large meals. – Mark Jan 5 at 10:45
What kind of physical labour are we talking about? Horses are not notably good at swinging pickaxes, for example. – Mike Scott Jan 5 at 13:22
@Mindwin, training a horse (or a dog) to accept magic takes years, and even then often ends in failure: it works maybe one time in a hundred, but having an ultra-fast (or ultra-strong) horse, or a dog with hyper-acute senses is valuable enough for some tasks that people still do it. – Mark Jan 5 at 19:42

Horses, always horses

It boils down to economic factor:

Why do we replace humans with machines? Sometimes the first version of the machine can do less work than trained human. So why do we do it?

Because in most cases horses and machines cost you less

Take this example: Augmented human asks for an hour of really hard work one piece of gold.

For same amount of work, in same conditions, an hour of horsepower cost you half a piece. We have winner!

Plus, you have benefit with horses: They do not require salary raises, they do not want to go on holiday, they do not have desire to go home to be with family...

So in nutshell: If hour of horsepower cost you same or less than hour of augmented human work, you will use horses.

In our world, people went to the machines for simple reason, that machines and horses cost you less. If you want to have lot of augmented people, their work has to cost less than cost of owning a horse.

It does not mean augmented people do not exist, they would be minority and working in fields/professions where you cannot use horses (or machines). Augmented people would be real professionals in your world

share|improve this answer
Are your numbers for relative cost coming from anywhere besides thin air? – Mark Jan 5 at 7:36
@mark I will update the answer a bit to make it more clear. The numbers are examples, so in nutshell they do come from thin air – Pavel Janicek Jan 5 at 7:59
Cost isn't the only reason we went with horses: in the absence of magical augmentation, a horse can manage about ten times the sustained power output of a human. – Mark Jan 5 at 8:43
This answer seems to assume a level of scarcity (and, thus, expense) of untrained human labor that, while typical of modern first-world societies, has generally not been common historically. At a base subsistence level, a horse is quite a bit more expensive to feed and maintain than a human (especially in urban environments, or during winter in cold climates, where you can't just set the horse out to pasture when it's not working). – Ilmari Karonen Jan 5 at 10:34
If we base our numbers on Britain from around 800-1200 AD, a prime stallion trained for war would cost perhaps 400x a day's wage of a regular, strong, free man. A regular horse would be more like 100x. Keeping the horse would be a fairly trivial amount, so we'd expect "buying a horse" to break even over "hiring a man" after around 3-4 months of ownership. I'd assume that augments would charge more than a regular man, so it would be cheaper to use a horse even faster... – Jon Story Jan 5 at 15:47

You need to look at the social factors as well. Are you looking at a modern world with a middle class and people expecting a decent daily wage or a highly stratified feudal society with mages/lords at the top and everyone else basically serfs.

If it's the former then it's one person with a team of horses. Simply a matter of cost.

If the latter then peasants are cheap and don't need paying. Remember that serfdom wasn't abolished in Europe until the mid 19th Century.

Considering a "modern" society, non-feudal with mid 18thC tech what you want are mules.

Mules are "more patient, sure-footed, hardy and long-lived than horses, and they are considered less obstinate, faster, and more intelligent than donkeys.

They're also cheaper to run as they'll eat less than a horse of equivalent size. We don't tend to breed them so much these days but they were a staple of long distance transport for thousands of years.

Mules have been deliberately bred by humans since the Book of Genesis was first put down on parchment. The Hittites thought Mules to be more valuable than a chariot horse, and the mule was the favored mount of the Kings of Israel in biblical times. The exact origin of the first mule is unknown, but we do know that the mule was deliberately bred by man in ancient times.

On plains wagon trains that used mules instead of horses, they could travel 30 miles a day, while wagon trains with horses or oxen could only average about five miles per day. In the west, stage coaches preferred mules over horses because large mules could travel at 5-6 mph over flat dry land for hours, but a horse would give out long before a mule would.

Mules every time.

share|improve this answer
I'm trying for a mid-1800s-America-ish society. Unskilled labor is cheap but not serfdom-level cheap, there's a distinct professional class separate from the ruling class and the laborers, and elementary magic use is considered part of a basic education much the way arithmetic or reading is. – Mark Jan 5 at 10:11
That's tail end of slavery, I'm assuming you're avoiding that. Mind you slaves are more expensive than serfs. – Separatrix Jan 5 at 10:37

I see a scenario where magic-augumented humans would do all the work: Magic analysis started thousands years ago before Neolith, when humans were homo sapiens, but they were exclusively hunter-gatherer tribes - they didn't know agriculture, didn't domesticated any animals.

If they started to grow plants and already had some basic spells, maybe it wouldn't make sense for them to domesticate horses/oxen; they preferred to enhance their magical abilities because it was more fun. And so the "magic revolution" went along the agricultural revolution, they fueled each other.

You suggest 18th-century level in comments. If each farmer can afford his fields being plowed, I think such civilization is perfectly achievable economically.

You need to watch your language though, idioms like "to hold one's horses" or "put the cart before the horse" or comparisons like "horseshoe shape" would be out of universe.

Side note: Maybe they didn't also domesticate chickens, pigs, etc - a potential for ongoing evolution toward vegan world scenario; in 17th-18th century mass hunting might become uneconomical and fell out of favor.

share|improve this answer

I agree with Pavel - horses, in general. For me, primarily, due to psychological reasons.

If the work really is purely physical as per your example of pulling heavy loads, then most people are going to find it extremely boring. You aren't going to get many of your willing subjects to begin with, and how long will they remain willing?

Breaking rocks was used as a punishment - why would people choose to do similar unless you are willing to pay them a lot more than the equivalent of horsefeed?

A couple of caveats:

You could of course get over these objections with user16295's social factors - scarcity of food so people HAVE to be willing, for example; also playing with the concept of "willing" - bonded labourers might be considered "willing" to pay off their debt? Either of these could actually make humans cheaper than a horse, which could be a very valuable beast, e.g. for non-magical transport.

share|improve this answer
Pulling or pushing a "plow" as a magic man is probably less boring that standing behind a pair of horses' butts the same time watching them do so. Not to mention the care the horses need after plowing is done. – Oldcat Jan 6 at 1:13
Well, it probably depends on what you enjoy doing I guess. I know a few people who think that caring for a horse is basically heaven on a stick, but they probably wouldn't think yanking a plough around the place was much fun :D – Whelkaholism Jan 6 at 10:07
Those pet horses aren't plowhorses. When everyone needs a horse, or two, the romantic part goes away fast. Reading about even generals and their horses you see that even that situation, horses are described in pragmatic terms - rides easy, stays calm, has a nice gait. It is more like how a commuter talks about his car, rather than how car nuts talk about them. – Oldcat Jan 6 at 17:31
That's an excellent point, which I hadn't thought of! But from a storytelling point of view I think I personally would still find it easier to write about people being enthused by the more varied work of animal care than pulling a plough. Although I once read an article about a guy who'd quit a high-flying City job to become a cleaner so he'd be able to work on his book in his head while pushing a vacuum around! – Whelkaholism Jan 8 at 10:11

Whatever is cheaper

Your version of magic may include conservation of energy (???), but any type of free-market system (that is, there's no law saying what you must use) will lean on conservation of profit. If the protag's in an area, there's going to be leaning on whatever is in large abundance - If the area is like Venice, you're going to leaning largely on water travel. If you're in an area where you can hire an augmented 'running man' cheaper than purchasing and maintaining a horse, camel, mule or dog team, you will. There are also externalities to consider -

If you're in a city or urban environment, do you want to deal with domesticated animal waste? Where are the animals kept when not being used?

If you're in a rural environment, how does the environment impact an augmented person? Rain, Heat, et cetera? (I'm thinking of the story of the British trying to use the Irish for Slave labor, but they couldn't take the heat in colonies, which led to the slave trade to Africa)

Are you advancing the plot in some manner? Is this a debate that the characters are experiencing, or the society as a whole is discussing? Are the augmented humans actually willing (skilled worker) or brainwashed to be willing (serf/slave)? Will there be a progression of enchantment, where today's work animals or augmented people pulling wagons will be replaced by self-pulling wagons?

share|improve this answer

In a comment I asked:

"animals that can be trained to accept spells are rare." - I think this point is easy to misinterpret in a variety of ways. For instance, is it the type of animal that can be trained which is rare? (Horses, but not Cows, Deer, or Zebra) Is it the difficulty of training particular types of animals? (anybody can train their dog to sit. To train a dog for much fancier things can require a smart dog and a lot of work - but people would probably do that much work for magic horses) Or is there some individual trait for some animals, or "Magic-proneness" any type of animal could have?

I believe this, along with the cost of manpower, is what will ultimately drive the decision.

Why? Because unless magical-acceptance is completely random, we will find a way to make them "not-so-rare".

  • Certain types of animals: Horses would presumably be one of them. Horses would be used all the way.

  • Training is difficult: New occupation of magical horse-training emerges. Horses would be preferred, but only available in locations with horse-trainers. Certain traits are easier for training, and are breedable (next point).

  • Animals require some kind of trait or intelligence which isn't random: Horse breeding takes place, just like it did in the past. At first, humans are more used. But as more horses are bred which are capable of magic, they become cheaper and more available.

  • Completely random - magical horses will always be rare for magical reasons, magical horses are only for the incredibly rich: Depends on local cost - which is more costly, magic or basic horse? Look to the next section:

Consider the following for each physical labor situation:

  1. How many humans/magic horses/normal horses would you need?
  2. How many of each could you possibly purchase/hire, and supply? (food, gear, etc.) How expensive are the supplies?
  3. Can you effectively run that many at once or watch over that many? How many men would you need to hire to supervise? (or do they not even need to be worked or watched?)
  4. After figuring out the cost of multiple compositions of humans+horses, Weight the decision more-or-less towards whichever method requires less direct work for the land-owner.
share|improve this answer
For instance, if I only needed one human, or one horse, if the cost of maintaining magic or stabling the horse is the same, you end up with three possibilities 1) do it yourself 2) guide a horse 3) hire another person - just like in today's world, doing it yourself takes the most work, costs the least. Guiding a horse takes less work for the same cost, so it would be preferred compared to the first - but if its a one-time task you may not always need a horse on hand. Hiring it done is always most expensive and most preferred (assuming its done well), because it doesn't take any work! – DoubleDouble Jan 6 at 0:02

I didn't see this addressed in any of the other answers, but essentially it boils down to:

Whatever is most cost effective for the job

As @PavelJanicek gets at, horses will always be cheaper.


Horses aren't very clever and are not very good at adapting to rapidly changing work conditions. They're good for jobs where an increased amount of brute force has a linear increase in work produced.

Humans on the other hand, augmented, magical, or otherwise, can handle rapidly shifting conditions where the "goal" is an abstract concept and which flexibility and creativity is more important than sheer power.

You know that thing about monkeys and typewriters? Well, we don't employ an infinite number of monkeys because while individually they're paid peanuts, and the produced result is quantitatively very high, the quality is rather poor: it takes almost as much work from an intelligent human to sift through the crap (pardon the pun) in order to find those works of Shakespeare than it would be to just employ the human in writing it in the first place. As an added benefit, you save the cost of an infinite number of peanuts.


Your augmented humans would be used in scenarios where their brains are more important than their brawn: the ability to identify strangers, perceive threats and dangers, or perform delicate manipulation (even with the strength of a horse, human fingers are a tad more nimble than hooves).

Search and rescue would be a good example: collapsed buildings, avalanche zones, etc. but by no means the only place. Factory machinine might also be a good place. Lots of strength, requiring less energy keeping the forges hot (because the guy can just bend metal bars with his bare hands) along with all of the creative ingenuity the human mind can bring to bear.

But as a general rule, any job that can be performed better by merely increasing the employee's strength will go to the horse.

That's why even though in the real world we've replaced horses and humans with increasingly complex machines, but we've not had the unemployment crisis that laying off all of those unskilled workers would logically represent: instead they find jobs that the machines can't yet do such as keeping the machines oiled.

share|improve this answer

Sorry to go against the premise, but you would use a forklift.

It requires 10J of energy to lift 1 kg by 1 m.

To, say, pump 100 L of water from a river to an adjacent house (3 metres above river level), roughly what a family would use in a day would require 3 kJ, which would require the wizard to eat 500 grams of rice to provide the energy. This is quite a lot of energy just to cover one task that technology currently does, and is if you live very close to a water source.

There are limits to how much we can eat, just based on some physical limitations on how fast we can breakdown food. We would not be able to compete with technology running on fossil fuels or renewables because of the energy requirements.

Technology will always be better than magic that obeys conservation of energy.

share|improve this answer
One of us is making a conversion error somewhere. According to my math, the 3 kJ for pumping water requires 3000 J * 1 cal/4.2J = 714 small-"c" calories, or 0.7 food Calories, about what you'd get from a dozen grains of rice. – Mark Jan 6 at 0:29
I think you might have an issue with the amount of calories provided by rice (the 714 calories/0.7 Calories conversion checks out). A source that uses calories says 184 g of rice has 242 calories (0.242 Calories), so 660 grams would be required, broadly consistent with my 500 grams. But I tend to get confused using 2 different units of energy that aren't SI units, so I could be wrong. – Scott Jan 6 at 0:44
I know its not a good source, but wikipedia suggests the big-C "food Calories" is widely used as a unit of food energy. It is unclear from the source website whether it is 0.242 Calories or 242 Calories otherwise - but my intuition guesses the 2nd. 1 lower-c calorie is supposed to raise 1 gram of water 1 degree. A pencap is about a gram. – DoubleDouble Jan 6 at 1:00
I'm sorry, I meant the first, if I burned a cup of rice I would expect the water to go up a couple hundred degrees, not a couple hundred thousand. – DoubleDouble Jan 6 at 1:24

Thinking outside-the-box... if magic is cheap, instead of a human or horse why not conjure an obedient troll or giant and dismiss him at the end of the work day?

You wouldn't have to pay out money or oats then.

share|improve this answer
What would you cast your conjuration spell on? You need a subject for your spell, and that subject needs to be willing. – Mark Jan 5 at 19:51
Ah... I was hoping conjuration would be exempt from the "needs a target" rule, since by definition it's producing something out of nothing. So your world has no conjuration. Transfiguration might work. – Adam J Richardson Jan 7 at 16:40

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.