A world much like earth has a society which, although rather aware of metals, does not possess the knowledge or resources to refine ore and produces alloys. They have access to practically unlimited wood and a variety of stone and volcanic glasses, but the only metals they can utilize are whatever native examples are found in the ground.

Would they be able to develop semi-robust computing?

It would be bulky, but surely not impossible to develop non-electrical analytic devices: it has already been developed. Could it be done without metals, though?

More importantly, would it? Assuming the society lived in peace and relative comfort, able to pursue academic issues at ease, and had fully optimized wooden/stone construction and tools, I imagine would have a relatively developed society. Would they conceive of and pursue the construction of a metal-free computer?

  • $\begingroup$ Isn't this a duplicate of worldbuilding.stackexchange.com/questions/968/…? Or am I missing something? EDIT: nope, it's me. Good question! (Which I can't answer.) $\endgroup$
    – CAgrippa
    Oct 3 '14 at 21:41
  • $\begingroup$ The Byzantines, although heavily dependent on metal, put together the first machines that could be considered computers...incredibly complex machines of gears and pulleys and levers that performed a very dedicated task and nothing else. I can see this type of computing through the use of wood and glass...however I don't think it's possible to apply miniaturization to these without the advent of electricity...and I have problems envisioning electrical components without using metal. $\endgroup$
    – Twelfth
    Oct 3 '14 at 22:23
  • $\begingroup$ Mechanical computers are grindingly slow compared to electronic ones. You would not be playing pong. It would probably take a good couple of minutes of cranking to execute even the simplest of programs. $\endgroup$ Oct 20 '14 at 16:38
  • $\begingroup$ What about an optical computer? Do they have glass and the capability to grind a lens? $\endgroup$ Oct 20 '14 at 16:40
  • $\begingroup$ The mechanical computers were already here thousands of years ago: en.wikipedia.org/wiki/Abacus $\endgroup$
    – Pedro Rolo
    Nov 18 '14 at 17:26

I note that you ask about computing rather than computers. This makes me consider computing as an abstract process, separate from the modern usage of "computer" to mean a machine. Before we had such machines, the word computer meant a person who computes.

Human parallel computing

The first parallel computation was put into practice without automated computing machines. For example, during the Manhattan project teams of human computers performed calculations for physical simulations. Richard Feynman improved the speed at which these simulations could be completed by finding a way to split up the calculations so that all of the human computers could be simultaneously working on the same simulation in parallel.

These calculations were aided by manual electromechanical adding machines, but in principal the same could be done by a group of humans with nothing but pen and paper and a strict set of rules for how to pass messages.

So the answer is yes, a society could develop computing, even without any machinery at all. If your society has access to other methods of speeding up calculation that don't require metal (even an abacus can be used for surprisingly high speed calculation) then teams of people can provide high speed computing services. Over time as people work on improving performance by identifying bottlenecks, more and more of the process may become automated, making use of techniques that we have never had to seek out since we already have metal.

In a society without computing machines the people employing these teams of trained human computers would become very wealthy due to demand for the advantages that computing power brings. Similarly to in our world, huge amounts of money could be poured into research into how to improve the computing process.

Example improvements

Once individual human computers are capable of completing their assigned calculations incredibly quickly (using aids like an abacus and an extensive knowledge of calculation shortcuts), the bottleneck is likely to be communication. Advances may then include arranging the human computers in geometric patterns that give them quick communication with as many neighbours as possible, and systems for passing messages over longer distances so that they are not restricted to passing messages from one neighbour to the next. For example a system of pulleys and string for connections to a selection of people several metres away, and a system of passing abacus-like temporary stored messages to immediate neighbours.

Unlike our electronic computers, which are huge arrays of bits all treated in the same way, human parallel computers may have a large number of separate specialised areas. Perhaps 10 or 20 people arranged to perform a specific function that is used by many other areas of a system of perhaps hundreds of people.


A system based on humans may sound unreliable, but so is a system based on bits. Errors are common with electronic memory and processors, but error correction is used to make this almost never a problem. Similar approaches could be taken with human computers, including multiple redundancy so that if some people give the wrong results to their step in the calculation there are enough double checks that the overall result is still correct with very high probability. This would also allow for people to leave their position to attend to the need to eat, drink or use the toilet without having to interrupt the larger scale calculation. This makes it simple to arrange for 24 hour calculation - a brief pause at one position while a person is replaced at the end of their shift does not cause problems overall.

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    $\begingroup$ Very interesting answer which approached the question from a totally different angle than I expected. Thank you! $\endgroup$
    – neph
    Oct 4 '14 at 22:40
  • $\begingroup$ @kikjezrous thank you! That's the nice thing about having answers from a large pool of people. There are so many perspectives... $\endgroup$
    – trichoplax
    Oct 4 '14 at 23:47
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    $\begingroup$ Man, this answer reminds me how badly I need to learn how to use my abacuses, I can barely add 1 and 1 on them! :P The "human parallel computing" angle is brilliant though, excellent outside-the-box thinking! $\endgroup$
    – Kromey
    Oct 6 '14 at 0:01
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    $\begingroup$ I imagine a city filled with scribes and clicking abacuses. Trained crows bring instructions and results from tower to tower, acting as network packets. People crowd around the gates, bringing questions and receiving their answers after days' time. Very cool visual, good answer. $\endgroup$ Oct 7 '14 at 18:05
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    $\begingroup$ The science fiction novel Souls In The Great Machine by en.wikipedia.org/wiki/Sean_McMullen contains a human powered computer. I forget what it was used for though. $\endgroup$ Oct 8 '14 at 14:51


Mechanical computing is indeed a thing. And while our own examples use metal components, they could really be made of just about any material the society could form into the necessary bits and bobs, albeit with some special considerations (e.g. wooden components would be susceptible to changes in ambient humidity, and gum up quickly if liquid lubricants are used). You'd never reach the miniaturization that electronic logic gates can achieve, of course, and computational speed would be limited by the durability, rigidity, and precision of your mechanical components at least as much as by your design itself. But it could be done.

There are some limitations. As mentioned, wood is susceptible to changes in humidity (and temperature, while we're at it). This is why woodworks clocks are not, and likely never could have become, precision timekeeping instruments, and similar limitations would affect woodworks computers -- including leading to woodworks computers that won't even work at all except in very particular weather conditions!

Stone has other difficulties, primarily arising from the difficulty of making precision components such as gears. That's largely just a function of tools and methods, though, and a sufficiently advanced society that's built on stoneworks would likely have overcome many of these challenges. A stoneworks computer, however, would sound an awful lot like a billion billion fingernails being scraped across a chalkboard simultaneously while it was running!

Would a society do this? In one that pursues academic studies, undoubtedly someone would think of the idea and ask, "Could this be done?" And that would inevitably lead to simple mechanical computers -- probably adding machines initially -- which would in turn lead others to ask the question, "What else could it do?" BAM! Computer revolution!

  • $\begingroup$ Yes! Just what I was going to say. Pity this never happened in our world. Charles Babbage had a lot of potential. . . $\endgroup$
    – HDE 226868
    Oct 5 '14 at 15:07
  • $\begingroup$ I made some logic gates out of Lego (i.e. purely mechanical pieces, no electronics) using a set/reset logic. Bulky and inefficient but made entirely out of plastic and not requiring precision engineering. $\endgroup$ Nov 18 '14 at 12:47
  • $\begingroup$ John Harrison made wooden clocks. They were actually quite good by the standards of the time. en.wikipedia.org/wiki/John_Harrison#Early_life $\endgroup$ Oct 31 '18 at 14:37

Yes but they would be faced by certain limitations:

  • It would be extremely hard to make computers both small and fast - in fact, fast as we understand it, would probably be completely out of the question.

  • They would be limited in use, bulky and expensive. That would slow down progress in computing sciences considerably.

  • They might not be susceptible to electrical problems, but they would have all kinds of other problems such as cracks, rupture, wear due to weather and environmental conditions at a much larger scale etc.

The primary advantages of silicon and copper based electronics are obviously size and cost first, but they also have the advantage of using electrical potentials which can switch at billions of times per second.

It is a well known engineering fact about computers, that making the parts simpler and making them switch faster is far preferable to making them complex and trying to get each to perform multiple jobs at once (as far as computational speed and efficiency is concerned). However, non-electrical computers would be forced to create swiss-army-chainsaws of modules to save space and material, increasing both complexity and operating with water, heat or chemical processes that are far slower in applying their effects, especially without miniaturized components (which often require computers to design and produce themselves).

Of course, one can assume light is the switching medium - the problem with light is, the only thing it can switch fast enough is materials sensitive to light and even then it produces microcurrents that require conductors to use. Piezoelectrics and other crystals can be used for this, but they are hard to work with without precision tools (although volcanic glass might allow a workaround).

A possible way to make this happen would be to have computers develop over a much longer period of time than in our reality and make them based on light as the switching medium, traveling through glass channels, using glass and crystals as logic gates and hand-crafted arrays of piezoelectrics (pressurized through small pistons? or small enough for light pressure to matter?) or something like that for memory and output. I'm not sure how close to this you can get without metals, or how small, but computers are more of a mechanism than a specific device made of plastic, silicon and doping metals.

But if we can make computers in Dwarf Fortress out of pressure plates, cattle and water, I guess it's just a matter of motivation in the end :P

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    $\begingroup$ p'shaw. everybody knows its pressure plates, gobbos, and magma. $\endgroup$
    – neph
    Oct 4 '14 at 0:05
  • $\begingroup$ Don't forget the etymology of the word 'computer', which dates back at least to the early 1600s. It wouldn't be what we call computers in daily language today, but it would be a computer. $\endgroup$
    – user
    Oct 4 '14 at 18:13
  • $\begingroup$ @MichaelKjörling I didn't forget it - but the question already mentions "semi-robust" which can only be interpreted in relation to the current state of computing and it does mention a non-electrical version, so I assumed the OP means something closer to our modern computing than just computers in the abstract sense. The abstract definition also creates confusion since even a thermostat can be considered a computing device, depending on your perspective. So I targeted what I thought was probably the intention behind the question. $\endgroup$
    – mechalynx
    Oct 4 '14 at 18:31

Analog computer

Without access to metal, but with a robust theory of mathematics, I'd expect to see huge numbers of special-purpose mechanical computers, ranging from specialized wooden slide rules to hydraulic or rope-and-pulley systems for simulating highly complex situations.

The general-purpose programmable computer, however, is not likely to appear.

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    $\begingroup$ Why do you believe general-purpose programmable computers would be unlikely to appear? $\endgroup$
    – Mr.Mindor
    Oct 3 '14 at 22:13
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    $\begingroup$ Turing machines don't have to be complicated to be turing. The programming would have to be, but the machine wouldn't. $\endgroup$
    – neph
    Oct 4 '14 at 0:06
  • $\begingroup$ It's the complexity of the programming that makes me think they won't appear: the earliest Turing-complete computers were only determined to be Turing-complete long after the fact because of how complex the programs would be. Why go to the effort of programming a general-purpose computer when you can build a special-purpose one in less time that will run faster? $\endgroup$
    – Mark
    Oct 5 '14 at 21:02

A society with optimized technological progress in wood and its other resources would most surely become interested in doing math faster at the very least, from there general purpose computers isn't a big leap. They would at the very least give a mechanical computer or water clock a shot.

As others have pointed out you can only really push those concepts so far. The space and speed become prohibitive to computation rather quickly and they become almost useless compared to paper and pencil.

As far as advancing beyond that we only have to look at our own history to see some routes that might be taken around metals. Chemistry and biology would certainly advance at some point, and the first light bulb used a bamboo filament instead of tungsten. Creating conductive plastics and chemical batteries would seem rather likely. And carbon based computers using graphite and the like would be a direction that could lead to some powerful computers if they managed to snag onto the idea. Possibly even conductive crystals, we do after all use quartz as a key component in many of our modern computers (the clock).

Of course, you would probably need at least a little elemental metal to kick-start research into conductivity, they need to start asking the right questions after all!

Lacking elemental metal I can see using biology to make computers out of neurons, with chemical soups replacing the need for metal. Possibly even a chemical computer could result from that research.

This would all require a significant amount of time, peace, and/or luck. With the requirement of a pre-refining society your chemical research would need to stay away from strongly exothermic reactions at the temperatures to smelt, which with the required advancement in chemistry would be highly unlikely. Which places strict limits on the allowed types of natural resource, lack of metal on the planet being the easiest to contemplate. The non-metallic world would need some fairly advanced mathematics and some deep insight into something like lightning on water for example to lead to research into conductivity.

So overall it would be almost certain to happen, but very unlikely on a planet with any form of metal.

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    $\begingroup$ Since nobody pointed it out I'd like to mention that the pre-refining requirement prevents you from using glass if there's metal around. The temperatures needed to melt it would almost certainly lead to smelting before computers. $\endgroup$
    – Black
    Oct 7 '14 at 14:33
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    $\begingroup$ Rolling around the site led me to this comment on a similar question: worldbuilding.stackexchange.com/questions/968/… which made me realize ceramic superconductors could be potentially be discovered. Something to ponder. $\endgroup$
    – Black
    Oct 7 '14 at 15:04

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