The world: A standard medieval European-ish fantasy world, with very limited magic, which aside from the titular exception has little to no effect on everyday life. The continent is divided into around a 60 petty kingdoms of about the same military power and technological level as Viking Age kingdoms had.

The scenario: while magic in the world usually proved underwhelming, under-powered and in general no more useful than its non-magical equivalent, one spell became surprisingly effective: Companion Rock Enchantment:

  • every human being is capable of casting this enchantment, as long as they talked to someone else's Rock beforehand (it takes a long, spiritual conversation with someone's Rock that "unlocks" their potential). Rocks are very reluctant to talk to anyone other than their Owner, unless the owner explicitly orders them to.
  • All it takes to create a Companion Rock is taking a fist-sized stone, carving eyes and a mouth onto it, and giving it a kiss.
  • resulting Companion is an immobile rock that has a mind as intelligent, knowledgeable and capable as its Owner at the moment of creation, but can learn. Its memory is not perfect, but superior to human due to better mental focus and not being easily distracted. It can speak, see, hear and smell as well as a human would even though it does not have organs to do so. The Rock is 100% devoted and loyal to its Owner. Being a piece of stone, it has no real emotions, but can pretend to emote if it pleases the Owner. Otherwise it remains stoic and relentlessly rational, in its pursuit of its goal: helping the Owner be safe, happy, and fulfilled. Otherwise, the personality of the Rock tends to be similar to its Owner, except more stoic, practical and rational.
  • A person can only have one Rock at a time. Enchanting a new one simply kills the old one.
  • Rocks that outlived their Owners bond with the next person that touches them, as long as it is someone without a Rock of their own.
  • otherwise, the Rock ownership cannot be sold, inherited, leased etc: either you enchant your own, or find an ownerless Rock.

The Question: how would the proliferation of the Rocks affect the economy? Lets assume that the economical situation when the Rock Enchantment is discovered is subsistence-level farming + rudimentary feudalism, and a vast, complex, but relatively low-volume continent-spanning trade. My question is mostly about economy/wealth generation, but if the answer requires delving into technological development, culture, etc this is more than welcome. Assume there are no religious or magical barriers to people using the Rocks to get rich and improve their lives, the only limits are their imagination and competition from others.

  • $\begingroup$ I wonder how we can answer such question? I think it 'doesn't matter' for the economy. The world is changed, so anything goes. There seems to be no limitation but your imagination how it would affect the story. Are companion rocks intelligent? Benevolent? What do they grasp of economics? In the end, aren't they just another form of a partner, which only changes the personal relationship to economy by the two personality interactions? Like, getting a husband or wife changes your economics, but that can be in anyvway depending on personalities. $\endgroup$
    – Trioxidane
    Apr 11 at 14:11
  • $\begingroup$ Would these rocks be immortal? At least if not destroyed? How about language? What if rock is bonded with new owner who does not speak same language? Does they keep intelligence, knowledge and capability of original owner or does they change to that of new owner? $\endgroup$
    – Ekaros
    Apr 11 at 14:55
  • $\begingroup$ @Trioxidane The Rocks are intelligent, but completely, myopically devoted to their Owner, so not "Benevolent" to others unless it benefits the Owner directly. Their initial grasp of economics is no better than their Owner, except they are coldly rational, and singularly focused on Owner's best interest. Rocks are essentially 100% devoted advisors, who never interact with anyone except the Owner, unless directly ordered to. They have no compunction against manipulating their Owner for their own good, or advising "pragmatically evil" solutions if it is optimal to do so. $\endgroup$ Apr 12 at 6:53
  • $\begingroup$ @Ekaros Rocks are immortal, but being picked by new Owner overwrites their personality, but not their skills or knowledge. Rocks always speak the native language of the Owner, but can be taught other languages. Rocks basically never interact with anyone except the Owner, unless Owner orders them to, (and even then begrudgingly) or if the Owner is in direct and immediate danger to their life. The only exception is an ownerless Rock who just bonds with the next person that touches them. $\endgroup$ Apr 12 at 7:02
  • $\begingroup$ If rocks will follow any orders from their owners, then there doesn't seem to be anything to stop the king from sending soldiers to levy a rock tax. i.e. Make a village deliver a hundred rocks commanded to general obedience; paint the rocks so you know who's to blame if they go dead; take them away and use them for watch duty, telegraphy, bureaucracy, etc. But maybe this isn't the kind of use you're interested in. $\endgroup$
    – Biro Cash
    Apr 12 at 10:09

10 Answers 10


Huge and far reaching impacts

First, it stands to reason that pretty much everyone will have one of these (except for children too young for speaking). Trying to keep it restricted to a small group will only work if it is kept a secret, and as the saying goes, two can keep a secret if one is dead. Eventually someone with a pet rock will leave any secret organization and share the knowledge with others (by ordering his rock to talk to someone).

Second, these rocks aren't just pets, they're essentially clones of their makers with physical limitations and some advantages. It is totally reasonable that rock owners would be able to hire out the labor of their rocks, or just use their rocks to enhance their own labor.

  1. See. There are plenty of jobs that mostly involve watching stuff. A castle guard spends most nights staring outside the castle wall, watching for intruders. A shepherd monitors the sheep and watches for threats. A sailor in a crows nest is watching for land and other ships. All or a portion of these jobs could be done by a pet rock. Reading (provided a way to turn pages). Inspection of military troops.
  2. Speak. Being able to sound an alarm or communicate what they experience is key to all of the jobs a rock can do. But here we can also consider other professions. A preacher can deliver a sermon in the morning and the rock can repeat it every hour while the priest does something else. A town crier rock can call out the time and distribute news. A teacher rock can give lessons, and even TEACH OTHER ROCKS!
  3. Hear and Smell. There are additional applications here such ask cook's assistant (it could even be put in an oven to monitor baking).

While not everyone will have a great use of a rock in their profession, the fact that they can hire their rock out for a fee will give a small economic benefit for any impoverished person, and before you object to that meaning that certain people would have the services of more than one rock, it would be rational for a rock of a beggar woman to hire itself off as a city watchman so that his person can eat meals.

  • 2
    $\begingroup$ i don't know if they have the ability to sound alarm because as the ability to talk to other people in such manner. As the author said they have a hard time trusting other people and don't normally talk to them. So while yes they would make good security cameras i don't think they are able to sound an alarm. $\endgroup$ Apr 12 at 11:21
  • 2
    $\begingroup$ @Fallenspacerockthe Rocks would be perfectly able to sound the alarm, but would be willing to do so only if specifically ordered by the Owner, or it it benefits the Owner. For example, a Rock might warn about a fire if Owner's house is in danger, but if the only dangers it to the neighbors, the Rock might decide it is better to let the pesky humans die in fire so the Owner can take their land. After all, only Owner matters, the rest is just tools/resources/competition to be used to benefit the beloved Owner and his faithful Rock. $\endgroup$ Apr 12 at 13:55
  • $\begingroup$ @Going Durden so it depends on the circumstances. I also had an idea that the rocks could be used as spy cameras. Like place them somewhere they are not noticed and then retrieve them later. $\endgroup$ Apr 12 at 16:10
  • 1
    $\begingroup$ @Fallenspacerock Or build them into the architecture. "We can't talk here. The walls have ears." $\endgroup$
    – Ray
    Apr 12 at 19:06
  • $\begingroup$ The city watch wouldn’t hire a beggar-woman, if she wanted to work for them — why would they be any more willing to hire her rock? $\endgroup$ Apr 12 at 19:28

The rocks are everything from self contained secure messaging (only say this to Bob) to account handlers, assuming their memories are good enough, From security cameras, to secret recording devices.

Being effectively immortal as they live forever unless killed, they also act as a permanent historical record.

However there isn't really an economy as we'd understand it in that period, and as such they wouldn't have much effect on it.


The broad impact:
Firstly i should tell you that this isn't at level of the printing press. But it will still bring some not completely inconsequential changes to your world's economy.

Distribution of Pet Rocks:
Yes you may have said that they can't be sold but that is not entirely true. Because there are 2. Ways i can think of.

  • Selling abandoned Pet Rocks:
    As you said it your self the only way to make a pet rock your self is getting another one to trust you. Which as we know takes very long. Not everyone has that time or the ability to do that to other factors. So why not take the shortcut and buy one. Picking up a pet rock can be done without directly touching them so why shouldn't someone collect and sell them? Ofcourse there are risks with that but for some people it would still be worth it.

  • Selling the ability to make them: It takes as you said a lot of trust to get a pet rock to teach you how to make them. So you have to get someone to allow you the exposure needed to make that happen. And not everybody would probably want their pet Rock to trust others for reasons*. This is where someone who sells you that exposure come in. Basically selling you the right to make pet rocks.

  • Beware the snakes oil sales man:
    Both methods leave lots of room for fraud. Basically it's probably difficult to distinguish a normal pet rock from a fake one. So why shouldn't someone make false pet rocks and sell them. Or sell the right to make them by convincing people to gain trust with a fake pet rock. Like these guys would be everywhere spreading a lot of lies about pet rocks to gaon profit. Simply saying people that when they buy a pet rock from him that they first need to gain their trust. So expect a lot of people to to lose money this way.

Economic use for pet rocks:
There are only 2. Ways they can be used. 1. Is basically having them as pets. But really would this effect your economic? Maybe as a substitute for dogs but ehh not really they don't have emotions and can't move so no.

A substitute for paper:
This one however has some substantial impact. Paper is really expensive in the era your world is set in. And your pet rock might be better than paper for several reasons. So it is safe to say it would be a good substitute for paper. Basically pushing the price of it down by as people have a better alternative. This could make more rare paper or make it cheaper depending on how well can manufacturers adapt. Though but want are the advantages?

1. They can store more information
2. They are a compact information storage device
3. No one except you has access to the information
4. Stealing them is almost useless

So yeah what you have basically created is USB-Drive. That only 1. Person can access so you can keep everything you say to it private*. This huge expect as compared to paper it is both more compact and no one can access it. Like expect it to be used keep states secrets or something.

Note: Sorry that it is so long i have the tendency to forget keeping my answers short. Hope this is not too much to read.


You made murder more beneficial

The first thing that instantly comes to my mind is a way to trade rocks by killing the owner and delivering untouched rock to the client.

There could be royal aspect to that

It is easy to imagine that families would want to pass on their rock to the heir, that can create incentive to not acquire new rock pet but instead wait for your parent to die to have knowledge of your ancestors always with you that alone can change technology available to people not even speaking about trade.



They could be used as a literal fly-on-the wall to spy on your friends, and possibly enemies. Simply tell the rock to remember everything it hears, and then hid it somewhere in the room you want to monitor. Retrieve it later, and ask it to tell you all it heard, and if you didn't fully conceal it, what it saw.


My gut feeling is that the rocks would have massive social implications, though it requires a lot of imagination to figure out what all those implications might be. The social effects will lead to economic ramifications. Some things to consider:

Propagation: I expect the rocks to quickly become valuable enough that everyone will want one, and will be willing to go to the effort of learning how to create one. Which means that the discovery will propagate out, people will attempt to restrict it, and those attempts will fail but cause a lot of disruption in the meantime. cf Chinese control of silkworms.

This will have some intense short-term economic effects, as people try to keep the process secret in order to create artificial scarcity. Early on, lords will pay enormous sums to be able to create their own. Which leads very quickly to...

Murder. If you want the ability to create pet rocks, what better way than to murder the owner of one, have your sworn lackey adopt it, and then your lackey will instruct the rock to teach you how to create your own? (If the lackey wants a more personalized rock, they are always free to get the rock to teach them the enchantment, and then murder that rock in the creation of their personalized version.)

This is not just an early-stage thing, though. If someone has important information that they can be expected to have shared with their rock, then the value of that information is no longer useful in keeping that person alive. You can always kill them and have a lackey adopt their rock, leaking everything it knows. This could be such a risk that powerful people adopt the convention of not sharing important information with their rocks, and letting that be known. Alternatively and similarly, powerful people may have servants that carry "blank" rocks. In the event of their master's death, they are instructed to adopt the master's old rock, and then immediately enchant their blank rock to "wipe" the sensitive data. Of course, they may only pretend to do so, so the bodyguards may know a factoid to use as a cross-check... which itself becomes a valuable target for corruption.

Archiving. This is a more directly economic thing. When a wise sage or strategically important person dies, their rock will immediately become highly valuable. The market price of these rocks, real or fake, will be quite high. I wouldn't expect this to have a huge impact on the economy, though; it will be common to extract the knowledge in written form. The scribes who do so will require specialized expertise, and their guild could become fairly respected and powerful.

"Coprocessor" Although I expect most people to be fond enough of themselves to want a personalized rock, certainly some percentage of people will prefer to take advantage of rocks created by someone they regard as smarter and wiser than themselves to assist them in accomplishing things they would not manage on their own. This would create a market in rocks.

Actually, this brings up an important need for clarification: I've been assuming that a given person can only produce one enchanted rock that is imprinted with their intelligence, which means a very limited supply of high-quality rocks: people who want a good rock will need one from someone who is either dead or not making use of their personalized rock. However, the rules are not clear: if person A enchants a rock R1 and gives it to person B, can person A then create another rock R2 and give it to someone else (or use it themselves)? Because if so, this would create a massive market for high-quality rocks. It would also mean that respected thinkers would have a major source of revenue available to them, which would reshape society and have a substantial impact on the economy—you can get paid for being smart! (Or selling yourself as smart; it would foster enormous competition. And you can't entirely just fake it, since people will pay attention to how well owners of "your" rocks do.)

I'm trying to avoid going too much into why I expect the rocks to be so useful and valuable, since that is not the focus of the question. I'll just say that regarding them as USB drives is underselling them. They're closer to smart phones, maybe, though without the communication aspects. (They are quite valuable for communication, but you can't use them for other purposes at the same time. And they are dangerous to let out of your immediate possession. Or if not dangerous, then it's still a high opportunity cost.) They are sentient! That's far more useful than simple storage.

  • $\begingroup$ As written, as soon as they create R2 then R1 dies, even if they'd given it away in the meantime. Which could be another kind of fraud -- you sell your rock to someone, then create a new one so the original becomes worthless. But then, once these rules become widely known, nobody would be willing to buy rocks anyway. I'm not sure about the murder aspect, though. Presumably rocks would be reluctant to divulge their previous owner's secrets to another even when inherited, especially if their previous owner were murdered, and doubly so if the new owner was a known associate. $\endgroup$
    – Miral
    Apr 12 at 6:52
  • 1
    $\begingroup$ @Miral Rocks are 100% devoted to an Owner until the Owner dies, then immediately switch to new Owner when picked up, with no moral remorse. Whoever is their current Owner is basically their best friend, true love and God in one. They see other humans as just tools, and other Rocks as, at best, potential temporary allies, but usually as dangerous competition. So, a Rock you Own will divulge all the secrets of the previous owner, no problem. It will even include thorough analysis how to use these secrets for your benefit, and encourage you to use them if it is optimal to do so. $\endgroup$ Apr 12 at 7:16

One economic impact is reliable transfer of generational and institutional information. Think of master craftsman and artisans passing their rocks to inheritors or favourite apprentices. These rocks would have collected lot of information and experience over generations. They could have tirelessly observed work of their owners generation after generation. And describe them in good detail to later owners. It might be that no technique is lost or not passed to next generation. This could also be used to authenticate certain works of art for example.

They could also be very useful in agriculture having observed many years and cycles. Maybe they could notice something new owner has not seen before and inform them about it. This also works in areas like medicine.

If they have learned and retain memories of foreign languages, products, trade routes and such they would be exceedingly useful in trade too. Having reliable translator is always useful.


Not very much, and a lot.

This is difficult to answer because it depends so much on the character of the rocks: their imagination and initiative, and how adept they are at persuading their owners to follow narrow self-interest. These are hard qualities to specify in a hypothetical.

Because it makes the question more manageable, I'll assume fairly passive rocks, unwilling or incapable of driving the typical owner to significant lifestyle change. (Rock: "This soil is bad, you should emigrate." Peasant: "Shut up.") In that case...

In the short term: not very much. The rocks provide moderate utility as tools, and double the practical intelligence of a Malthusian society which isn't at all intelligence-bound. I'd guess that their practical uses plus their diligence & cold perspective would grant a big one-off boost to the efficiency of everything: maybe something like 30%? Alas regardless of its size, this gain would be easily absorbed by population growth - one golden generation then a swift return to near-subsistence.

In the long term: a lot, but unspectacularly. Rock rationality would be a powerful tool for any innovator, but innovators would remain extremely rare. It's easy to imagine rock advisors doubling every innovator's achievements, but doubling the medieval rate of productivity increase from (say) 0.3% to 0.6% is still only going to be visible over the course of centuries.


Scientific and Literary Advances

So it seems like what your rocks can do, is think (with an intelligence of its owner) and speak. Being small pieces of stone, they cannot do any physical labour, or fight, or dance or anything else requiring the use of a human body. So they will not make a lot of economic difference to people doing anything physical, such as peasants (which will be the vast majority of people in a medieval world), except maybe to make them a little happier.

They will, however, make a lot of difference to people whose work mainly involves thinking and speaking. There will be some benefit to priests, maybe to people selling goods at the market, maybe to actors and mimes (although, no matter how well a rock can imitate their voice, their performance would still be a lot more compelling when delivered by a human rather than a piece of stone).

There may be some benefit to nobles, but I feel it will be limited. They could, for example, try to get their pet rock to hold court, or deal with complaints of some petty courtier while they do something more fun, but doing so would probably cause pretty serious offense and is not something they would be able to do often.

The rocks could make some difference in courtly intrigue. A noble could hide their pet rock somewhere they think people conspiring against them could meet, and then have the rock tell them everything it's heard. I'm not sure how much difference that would make to the economy of your world.

The main difference, I feel, would be for people like teachers lecturing at universities (if you have universities in your world), monks studying some old manuscripts, people writing and/or translating books. You've just more or less cloned every thinker of any significance in your world. The result will be faster scientific and cultural advances across the continent.

  • $\begingroup$ how long until the rocks get networked? $\endgroup$
    – fraxinus
    Apr 13 at 12:43

While the lack of technological and economic development would retard a lot of change, there would still be a lot.

People would compete to have their rock be the best at a particular skill such as a modern spelling-bee for example. Certain rocks would become famous, be pampered and live in comfort. Others might try to kill their owners and steal them. People would write books on how to treat your rock and how to put it to good use. People would find unethical uses of rocks and a new criminal enterprise would be opened. You might try to disguise so you can spy or have it pretend to be another rock.

I would approach the question by ignoring the rock aspect and thinking about the rock as an immobile or disabled person.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .