Techs Ordered By The Earliest State A Civilization Could Have Them

[civilizationfanatic2000]

This is simple. Order techs by how early a civilization could have discovered them, not when they were discovered in our world. There are many ways to balance this.

 

[Evie]

"When they could have discovered it" is an incredibly complex question that is not so easily answered and requires a lot of hindsight and assuming the best.

In any event, it's not actually an important question, as what governs when techs are discovered in game isn't when they were discovered - it's what their prerequisire are.

And tech penalties on early research are sensible: often the difference between "when it could have ben discovered" and "when it was discovered" is precisely that while they had all the right tools, they lacked the motivation or knowledge base to properly develop that technology.

 

[The_goggles_do_nothing]

There's a design technique where you pretend you are a "persona" - a doctor, a child, and skier, etc.. and then come up with as many "As a (persona), I need to..". Applying that to civ, you could start of with "As a new civ in 2000 BC, I need to house myself, feed myself, protect myself from Barbs.." If you have fish avaialbe to your first city, you would have fishing available. If you have fertile ground, farming.

 

[Boris Gudenuf]

Using 'Needs' as a basis for Tech and other advances is an idea I have fiddled with in the past, but not gotten very far with it because it is really Open-Ended.

For example, NEED to protect my Civ from Barbarian raids could result in:

1. Better Weapons for my defensive forces - Iron Working, armored cavalry, better fortifications - and note that these may each be separate and multiple new technologies.

2. Buy them off.

3. Bigger Defensive Forces - introduce Conscription, or long-term enlistment (the Imperial Roman Army's 25 years, for instance) or require every farmer to show up when called with weapons - and note that, again, this set of 'solutions' might each require a new Civic/Social Policy with Unforeseen Consequences besides the military.

4. Hire Them, or other people's forces to defend you. Again, with potentially Unforeseen Consequences in the future.

Which only goes to show that a simple NEED requirement applies to all types of possible 'solutions', technological, political, economic, civic, or social (and, possibly, Religious, as in Convert them to your own religion and then recruit or co-opt them).

And, back to the OP briefly, when a new Technology (or Social Policy or Government, for that matter) might be possible is another Open Ended Question. As a thoroughly Off The Wall example, it has been pointed out that by the 2nd century CE the Romans had all the technology necessary to start building Steam Engines: the crank and connecting rod to transmit power, Hero’s areolipile generating steam pressure/power, the cylinder and piston from metal force pumps, non-return valves from water pumps, gearing from water mills. And based on their waterwheel-powered saws that cut marble slabs to 0.6 inch thickness with less breakage than modern power tools can manage and the gear teeth in the Antikythera Mechanism of 200+ years earlier, they had the capability of making mechanisms with at least as much precision as Watt's original steam engine of the 18th century CE.

So, there is at least a 1500 year gap between Could Have and Did in this instance. Likewise, making Pottery containers starts anywhere from 18,000 BCE (China), 7000 BCE (Europe), to 1600 BCE (Polynesia) - that's a more than 16,000 year difference, or more than two and a half times longer than the game is designed to last! Similar 'spreads' between Started and Caught Up could be entered for things like Archery (6000 BCE in Europe, 3000 BCE in the Americas), Steel making (400 BCE in India, 1200 CE in Europe), etc.

I suspect to manage a model that accounts not only for When someone can Start and also Why They Did Not will require a massive compilation of Needs, Raw Materials, Prior Technologies and their Applications - including non-historical but 'potential' ones like Hero's work with hydraulics, water and steam pressure devices, and Social, Civic, Religious and Political factors.

Basically, redesign not only the Tech Tree, but the entire game from the ground up.

 

[Marla_Singer]

And based on their waterwheel-powered saws that cut marble slabs to 0.6 inch thickness with less breakage than modern power tools can manage and the gear teeth in the Antikythera Mechanism of 200+ years earlier, they had the capability of making mechanisms with at least as much precision as Watt's original steam engine of the 18th century CE.

It's funny how still nowadays historical perceptions are distorted from a country to another. Here in France we're tought that steam engine was invented by Denis Papin in the 17th century.

Anyway, steam engine seems like a simple idea: let's boil some water and then use air pressure as power, but getting it to work properly requires a solid understanding of the laws of physics, at a very theoretical level. The Romans had very good empirical knowledge of physics, but it wasn't properly theorized before Galileo and Newton.

 

[Boris Gudenuf]

It's funny how still nowadays historical perceptions are distorted from a country to another. Here in France we're tought that steam engine was invented by Denis Papin in the 17th century.

Anyway, steam engine seems like a simple idea: let's boil some water and then use air pressure as power, but getting it to work properly requires a solid understanding of the laws of physics, at a very theoretical level. The Romans had very good empirical knowledge of physics, but it wasn't properly theorized properly before Galileo and Newton.

Yes, I should have said "Watt's first practical steam engine". Papin's engines of 1690 and 1704, like other early attempts (Newcomen's for instance) were wretchedly inefficient because of a lack of a condenser and very imprecise matching of cylinders to pistons - they wasted most of the steam energy into the air. Watt's real advance was to add a condenser so that steam was 'reused' and used more efficiently, and using Wilkinson's new precision boring machines to produce cylinders with tight enough clearances to avoid the wastage in the older model engines.

As with most 'brilliant inventions' the steam engine as a workable, useful device required a number of 'inventions' and manufacturing/fabricating techniques to make it all work. That's why a Roman Steam Engine was only a Potential Development - we obviously have no real way of knowing whether they could have put all the requirements together to actually make it work.

 

[Marla_Singer]

I mentioned Galileo and Newton for their works on physics, but I could have also mentioned Torricelli and Pascal for their works on pressure. Now the question can be why weren’t Romans or Greeks able to theorize physics and develop the scientific method as it was elaborated during Renaissance.

 

[civilizationfanatic2000]

I mentioned Galileo and Newton for their works on physics, but I could have also mentioned Torricelli and Pascal for their works on pressure. Now the question can be why weren’t Romans or Greeks able to theorize physics and develop the scientific method as it was elaborated during Renaissance.

their philosophy said no. it's hard to explain, but greek philosophy didn't like empirical study and decided that since the world is rational, it is necessary. you could figure everything out in the universe by sitting in a room and using reason.

 

[Marla_Singer]

their philosophy said no. it's hard to explain, but greek philosophy didn't like empirical study and decided that since the world is rational, it is necessary. you could figure everything out in the universe by sitting in a room and using reason.

Maybe another factor is that Greeks and Romans didn't have Hindu-Arabic numerals, which made solving equations much more efficient, notably with zero and the ability to subdivide whole numbers with decimals. In Ancient times, calculations were mainly done in the head or using an abacus. It's pretty fascinating that Greece was still able to develop such advanced geometry in this context.

Reading a bit more about that on Wikipedia, the use of Arabic numerals in mathematics has been very progressive, over several centuries. In 12th-century Europe started an opposition between tradional abacists (performing calculation with an abacus) and algorists, pushing to develop calculations in a written form.

Now that I think about it, Hindu-Arabic numerals could make a great Civ technology. It's missing. We know the Arabs developed algebra at the end of the first millenium. If anyone could have developed the scientific method and physics first, perhaps it could have been the Arabs, Persians or Indians.

 

[Hellenism Salesman]

Now that I think about it, Hindu-Arabic numerals could make a great Civ technology. It's missing. We know the Arabs developed algebra at the end of the first millenium. If anyone could have developed the scientific method and physics first, perhaps it could have been the Arabs, Persians or Indians.

Now that you mention it, it's sort of ridiculous we only really have one Mathematics tech. That implies that- in the classical era- we discover everything from arithmetic to geometry to calculus all at once.

...which... is not how it happened...

edit: it can be assumed some other mathematical developments occur with other techs, but there are some important math-related things that don't get featured by the techs.

 

[Naokaukodem]

Greeks had the theoretical basis for steam machine, but couldn't construct them. There was simply no imaginable way to imagine how to build such heavy and resistant devices. Otherwise the industrial revolution would have happen BCE. This is the difference between Science (theory) and Technics (practice).

 

[Boris Gudenuf]

Greeks had the theoretical basis for steam machine, but couldn't construct them. There was simply no imaginable way to imagine how to build such heavy and resistant devices. Otherwise the industrial revolution would have happen BCE. This is the difference between Science (theory) and Technics (practice).

There are some intriguing hints to the contrary - but that's all they are.

515 BCE: the Greeks were using cranes with metal gearing to lift multi-ton stone into place to build monumental structures (a temple in Corinth, to be exact). This implies both the ability to construct complex machinery and handle large, heavy elements without relying entirely on unassisted muscle power.

201 - 100 BCE: The Antikythera mechanism indicates that the Greeks could build very accurate and intricate metal machinery even without the precision measuring devices and machine-made parts available after 1800 (look up Maudsley and machine-tools Technology)

60 CE - Pliny the Elder describes a mechanical harvester: "an enormous box with teeth, supported by two wheels" seen in Gaul. Unfortunately, we have no idea how complex this was, or how much was advanced metal fabrication, but another note indicates that some similar machine was in use in Gaul until around 400 CE, so it must have worked somehow.

before 200 CE: at Ephesus marble veneers were being cut with a water-powered sawmill to less than 1 inch thickness with less than 5% breakage (based on archeological findings of debris in the site), which is comparable to modern stone sawing - this indicates, along with the Antikythera mechanism, more precision possible in Classical engineering and construction and fabrication than was previously thought possible.

Which, of course, does not prove that they could have built a metal boiler, cylinders and pistons, piping and all the other components with the strength and precision to make even a primitive working steam engine like Papin's or Newcomen's, let alone Watt 's more sophisticated design. But it also makes it hard to say categorically that they could not have, or that the process of making even a poorly working steam power plant would not have spurred research into the principles behind it: the classical Greek philosophy that relied entirely on Reason rather than experimentation had already taken something of a back seat to the theoretical and practical work coming out of the Alexandrian Museon in the Hellenistic period, which produced such Empirical workers as Ptolemy, Galen, Euclid, and Dioscorides.
The synthesis of Greek and Near Eastern technologies and theoretical background at the Great Library produced a near-revolutionary change in traditional 'Greek' science.

 

[Boris Gudenuf]

Now that I think about it, Hindu-Arabic numerals could make a great Civ technology. It's missing. We know the Arabs developed algebra at the end of the first millenium. If anyone could have developed the scientific method and physics first, perhaps it could have been the Arabs, Persians or Indians.

Ahem. IF positional notation and the use of a symbol for 'Zero', the basic contributions attributed to the Hindi-Arabic numeral system, were to be the basis for a scientific method and physics, there are some more candidates:

around 3000 BCE positional notation and a 'zero' symbol show up in Sumerian inscriptions. Unfortunately, we have no idea how common they were, or if they were reserved for special numerical operations only (like astrology or religious subjects)

around 4 CE (which may have already been moved back: that's the earliest date I could find in some old notes) the Mayans were using positional notation and a zero symbol. Note that thery already had the complex calendrical system they are famous for, so unless the numeral system can be back-dated several hundred years, it was not required to do the complex calculations required to produce the calenders.

around 600 - 660 CE, both the first Indian writer to describe the place notation and zero system and its application to algebraic equations (Brahmagupta) and an inscription showing the zero notation in Cambodia - the latter may cast doubt on the exact origin of the system in southeast/south Asia. We know that it spread from India to Arabia/Persia by 800 CE, but can no longer be entirely sure it originated in India.

 

[Marla_Singer]

Ahem. IF positional notation and the use of a symbol for 'Zero', the basic contributions attributed to the Hindi-Arabic numeral system, were to be the basis for a scientific method and physics, there are some more candidates:

around 3000 BCE positional notation and a 'zero' symbol show up in Sumerian inscriptions. Unfortunately, we have no idea how common they were, or if they were reserved for special numerical operations only (like astrology or religious subjects)

around 4 CE (which may have already been moved back: that's the earliest date I could find in some old notes) the Mayans were using positional notation and a zero symbol. Note that thery already had the complex calendrical system they are famous for, so unless the numeral system can be back-dated several hundred years, it was not required to do the complex calculations required to produce the calenders.

around 600 - 660 CE, both the first Indian writer to describe the place notation and zero system and its application to algebraic equations (Brahmagupta) and an inscription showing the zero notation in Cambodia - the latter may cast doubt on the exact origin of the system in southeast/south Asia. We know that it spread from India to Arabia/Persia by 800 CE, but can no longer be entirely sure it originated in India.

You're right, rather than insisting on Hindu-Arabic numerals, the important factor is algebra in itself. Just to clarify, I agree with your main point which is that History isn't linear, that things could have happened differently. I also agree that Greeks and Romans were very advanced, with an extensive trade network giving them access to basically anything the world could offer. As such, I agree with the idea that an industrial revolution could have happened much earlier.

Yet, we can still wonder what was missing to them. As much as they built impressive aqueducts and amphitheatres, they could have never built a suspension bridge such as the Golden Gate nonetheless. And that's where we cannot discard the major scientific advances which happened prior to the industrial revolution, from Galileo to Euler or Lavoisier. What made it happen then and not before is an interesting question. As impressive as was Italian Renaissance back in the 14th century, Europe at the time still ignored many technologies developed across the world. It's really in the 17th century that Western Europe took a significant advantage. We've already had a conversation about that and I'm still convinced that it's the control of the high seas, and therefore global trade, which allowed Europe to concentrate all knowledge from the rest of the world, giving to it a pretty unique position.

To some extent that was largely the case of the Roman Empire, importing goods from as far as China, yet it never developed Algebra as extensively as the Persians and Arabs did from the 9th century onwards. Algebra has been very central to the development of science and techniques all through the second millennium CE.

 

[Boris Gudenuf]

To some extent that was largely the case of the Roman Empire, importing goods from as far as China, yet it never developed Algebra as extensively as the Persians and Arabs did from the 9th century onwards. Algebra has been very central to the development of science and techniques all through the second millennium CE.

Not specifically related to the game, but I have long held that while mathematics in all its advanced forms is essential to the development of the physical sciences and engineering, the so-called Social Sciences will not advance to anything near the same level until a Language is developed that handles Qualitative data as well as mathematics handles Numerical data.

Back to the game, another point on the usefulness of the positional notation/zero numerical system is that the evidence points to the use of them in Europe being almost confined to the northern Italian city states until the 15th century - giving them a distinct advantage in commercial calculations and possibly leading to the (re)invention of Banking in those cities in the 12th and 13th centuries. One piece of evidence for this is that the first indications of the use of the new system of numbers outside of Italy is in other commercial centers, such as Lyon in France.

So, possibly 'Place Value Numbers' could be a Core Technology that leads to a line of technologies like Banking and Economics and also a line of technologies in physical sciences like Physics, Ballistics, Steam Power, Scientific Theory, Chemistry, etc.

 

[BuchiTaton]

Dont forget that in CIV "Technologies" are mean to unlock units, buildings, ideologies* and abilities, so above any sequence of techs these should have a reason to be in game before anything else. This is relevant also for the era were the techs are asigned, considering the rate and period when new mechanics are available during the game. So the point of "how early X or Y tech could have been invented" is not that relevant or useful when the game by design and the playerbase by familiarity want a game where the Medieval era feels* medieval and Industrial era feels* industrial, setting is relevant and at this point after Humankind and Millennia I think is pretty obvious that an "open" tech tree for 6K years of human history would be a ballance nightmare and a flavorless hotchpotch.

 

[Boris Gudenuf]

Dont forget that in CIV "Technologies" are mean to unlock units, buildings, ideologies* and abilities, so above any sequence of techs these should have a reason to be in game before anything else. This is relevant also for the era were the techs are asigned, considering the rate and period when new mechanics are available during the game. So the point of "how early X or Y tech could have been invented" is not that relevant or useful when the game by design and the playerbase by familiarity want a game where the Medieval era feels* medieval and Industrial era feels* industrial, setting is relevant and at this point after Humankind and Millennia I think is pretty obvious that an "open" tech tree for 6K years of human history would be a ballance nightmare and a flavorless hotchpotch.

Of course Techs must have an in-game purpose or there's no point to them.

But the linear Tech Tree is arguably problematic for several reasons:
1. It is utterly predictable, so that after a few games you click the required next Tech mindlessly - boring
2. It inevitably Must be generalized, because no game could possibly explicitly model every technological advance in 6000 years. That generalization is where the Tech becomes to a degree Fictionalized. Every Tech Tree in every Civ game has had techs grossly out of place, or lacking the actual pre-requisites that made them possible, or are applied to constructions that had no connection to them at all.
3. Most importantly, the linear and single-sequence Tech Tree completely fails to show any other technological progression except European. Chinese had cast Iron, Indians Steel, Austronesians open-ocean sailing long before Europe? So sorry, unless it is represented by a Unique you wade through the same tech tree, same sequence as everybody else: no cutting the line no matter how different your in-game, on-map situation is.

Of course the Tech Tree cannot be completely without structure: this is a game, with rules and structure inherent in it. BUT it is long past time that the linear structure of the Tech Tree in Civ needs to be re-examined instead of, too often, simply accepting it as "the best we can do".

At the very least, all of the non-technological causes and affects of technological advances should be closely examined to disclose just how many 'extraneous' factors went into the tech advances represented by our trees. As an example, how much did having a history of near-continuous conflict, diplomatic or military, have on European technological advance in the 17th - 18th centuries? It has been argued that this was crucial to European developments in small arms, naval architecture, navigation and cannon technologies that gave them their massive 'edge' over China and the rest of the Far East. IF that is true, how to model that kind of effect in-game on the Tech Tree and the speed with which it can be traversed - with the added question, are only certain Techs affected or all of them?

 

[BuchiTaton]

Agree that examples from previous CIV games have many "Technologies" (even the use of Technology is debatable for many in-game) that stand out because of how questionable they are presented in game. But my main observation is that gameplay is above history, and clear popular history is more profitable than complex alter history.
There are many ways to represent and solve the noticeable "not in model" historical examples like:
- China had Crossbows, Gunpowder, Cast Iron, Compass, Printing, etc. Before Europe.

Easy, first most of these tech were implemented in China just one era earlier than in Europe, and that is already possible in CIV games, have a Medieval tech in Classical era and Renaissance* tech in Medieval is alredy an option for any civs that invest/have bonus for science. Also is for this that China is one of the most deserved civs to be Science based.​

- West Africa had an Iron Age without a Bronze Age.

In the traditional CIV design BronzeWorking is just before Iron Working, so ingame is possible to ignore military for some turns and then rush from Mining>Bronze>Iron even more with a good economy and the proper eurekas . Maybe it sound as a big risk to "ignore" military but CIV6's unlock of Encampment dont need to be replicated in CIV7.​

- The Native American use of metal.

Metalurgy as used by most American cultures was mainly for jewelry, this can be represented by a tech that do exactly that, provide early metals like Gold for cultural and economic purposes. The later Bronze working that alredy had a significative use on the Andes is on regular civ model and the early/limited use in Mesoamerica in civ terms is a civ that took to much time to developed and ended being in disadvantage because of this.​

About the "They dont used bronze/iron for cultural-economic reasons" these economic and cultural reasons have mostly geographical basis. Bronze and Iron working were not invented by every culture in the Old World, it was just in a very limited number of places and from there it spread, so most learned from their neighbors. Maybe it is not culturally or economically evident for isolated cultures to abandon things like obsidian when in their context it is good enough, but in CIV we dont play as a mortal leader of an isolated culture with no knowledge of the world outside and the future. WE play in a game where we are looking to a future of metallic flying machines, and in most games we are linked to others civs that likely have access to metal working. In a game were a turn can represent decades design a possible scenarios justifiying our non-iron using civ is a waste of time. Historically native american cultures learned very quickly that iron tools and weapons were useful and took or made them when possible. Non Bronze or Iron using civs only make sense in very early game when these techs were still being introduced, a civ that reach later eras withouth them in-game terms is a civ that started in a very bad place for it.​

Obsidian can be introduced as a resource with bonus for early militar units, but historical exceptions with long terms disadvantages make not sense for gameplay design.​

- Open Ocean Travel.

Seafearer cultures like Phoenicians, Greeks, Tamils, Malays had oversea colonies but these were still kind of "regional" in coast still linked by land to the homeland or between very close islands, then we have limited success from the Norse and the only early oceanic empire were the Tonga. So we have before anything a single real early deep ocean long distance state, highlighting state since Austronesian would not be a civ, the Malagasy, Javanese or Maori are more what a civ would be but they dont had long distance oversea empires, they reached in a "pre-gameplay" way a far land but their domain was not a trans-oceanic empire in the way Early Modern ones, so Tonga and maybe Norse are few exceptions that could be covered by their uniques.​

Still I have options like the suggestion to have earlier specializations to choose between Agrarian, Pastorial or Maritime societies bonus. Of course Maritime could add special units like earlier War Canoe units, this as a particular selection for the early game in a equivalent way to others societal optional paths in later eras (more *government" selection related).​

So even for the historical non-in model examples we have gameplay design options to explore, before design a whole technology model for those exceptions.

 

[Marla_Singer]

I think a good model that would make sense historically speaking and fit within a Civilization game would be the ability to exchange techs through trade. I don't know which forms could it take but you can imagine that once in a while you would get a message popping up telling you "Your merchants in Babylon discovered Code of Laws and brought it back home". That would incite players to expand trade relationship with as many civs as possible, making an interesting competition game between rival civilizations about who controls trade routes.

Also you could learn this way a technology without necessarily having the required techs to develop it by yourself. The reason why horseback riding appeared so late isn't because no one had the idea to ride an animal before it, but because it required many centuries of horse domestication and breeding to "develop" a horse that was docile enough to accept being ridden for travel use. And once that was the case, anyone who encountered such horses would grab them, ride them and breed them.

- Open Ocean Travel.

Seafearer cultures like Phoenicians, Greeks, Tamils, Malays had oversea colonies but these were still kind of "regional" in coast still linked by land to the homeland or between very close islands, then we have limited success from the Norse and the only early oceanic empire were the Tonga. So we have before anything a single real early deep ocean long distance state, highlighting state since Austronesian would not be a civ, the Malagasy, Javanese or Maori are more what a civ would be but they dont had long distance oversea empires, they reached in a "pre-gameplay" way a far land but their domain was not a trans-oceanic empire in the way Early Modern ones, so Tonga and maybe Norse are few exceptions that could be covered by their uniques.​

I agree. An area to be "discovered" doesn't require only the ability to reach it, but also to reliably return from it, otherwise there's no communication and therefore it couldn't be mapped. I'm sure that many Mediterranean sailors reached the Gulf of Guinea before the Portuguese, but as they weren't able to come back because of the strong streams off the Western Saharan coast, they were considered lost at sea. Who knows, maybe they could have settled a little civilization there (after all Africa wasn't that populated then), but considering they rarely had women aboard I guess they mixed up with locals instead.

To better picture Austronesian development accross the Pacific and Indian oceans, maybe an idea would be the ability to send settlers off the coast, but without knowing where they would land, if they ever landed, founding a distinct faction that we could rediscover later in the game. That could be funny even if I'm not sure that would really serve any purpose.

 

[Boris Gudenuf]

I think a good model that would make sense historically speaking and fit within a Civilization game would be the ability to exchange techs through trade. I don't know which forms could it take but you can imagine that once in a while you would get a message popping up telling you "Your merchants in Babylon discovered Code of Laws and brought it back home". That would incite players to expand trade relationship with as many civs as possible, making an interesting competition game between rival civilization about who controls trade routes.

Also you could learn this way a technology without necessarily having the required techs to develop it by yourself. The reason why horseback riding appeared so late isn't because no one had the idea to ride an animal before it, but because it required many centuries of horse domestication and breeding to "develop" a horse that was docile enough to accept being ridden for travel use. And once that was the case, anyone who encountered such horses would grab them, ride them and breed them.

A 'diffusion' mechanic is long overdue in the game. I just read an article about a recent study that tracked ancient chicken DNA and found that the domestic chicken was among the things that traveled the Silk Road across Central Asia between 400 BCE and 1000 CE. This gets added to the Moslem and Buddhist religions, silk and porcelain trade goods and advanced iron-working technologies that also joined the caravans (and several Plagues)

Both Technology and other Useful Diffusion definitely needs to be in the game. The breeding of horses for the two genes that enhanced docility and ability to carry weight on their backs was done in one place: north of the Caspian Sea. And the resulting domestic/domesticable horse spread so far and so rapidly that there are NO horses left in the world without those genes: which also means that the horses in Greece, Mesopotamia, India, and China were not found on the map there, they were Introduced complete with the already-developed genes for domestication. The spoked wheel chariot originated in roughly the same place, and within 2 - 300 years had spread to Shang China, Mesopotamia, Egypt, Mycenean Greece, and eastern Poland/Germany in Europe. In game terms, nobody else had to do much 'Research' to get chariots as long as the Tech started in the middle of the cross-continental network represented by the pastoral groups' trade contacts. Both a military unit and a Resource then, could Diffuse across trade routes - and pretty rapidly at that.

Quite a bit later, Gunpowder spread from China to both the Arabic and Christian European states. Nobody had to research Gunpowder, only what they could do with it - indicating that, perhaps, a Diffusion mechanic would also require separating Tech requirements for specific Applications like aquebusses, Bombards, and flintlock muskets (all except the Bombard 'diffused' back to China from Europe) from the Basic Technical 'breakthrough' of gunpowder (or Electricity, or 'Sailing')