It took us millennia to learn that quartz sand at 1800 degrees forms perfect silicon. Once we know that, and we've built a furnace aided by bellows, and found quartz sand, were not far away from having silicon.

I think most short cuts won't work as well. You only have a million people that also need to take care of their food and teaching needs, while not having all skills for a lot of it. Most of these advancements require more than just smiting. They require automation for huge quantities and sometimes advanced refinement. Building a factory with primitive tools and available resources will severely hamper advancement, as you just can't build it or build enough of it. Unfortunately you need a lot of different factories for advanced development.

The only problem with the idea of a "single minded organisation" is that this isn't really what we have. We have a large group of human people. We have elderly people, we have children, we have families, and they all have daily needs, concerns, and perspectives Some of these people will end up falling out with others and factions will arise. The human factor, I think, really can't be counted out.

The people however die on day 7 from starvation, as they have only their hands and you dedicated nobody to scavenge food.

@Trish were it random - probably; however the question says assume optimal climate / location.

@Trish 50% of their efforts are looking for food for the first 20 years. One person can harvest enough food for 2 people.

@Ash No, a person can't supply another without at least middle age technology tools. An archiaic subsistance farming community spends at least 80% of its work into producing food, 15 into maintaining the status quo against nature, 3 into teaching the next generation and spiritual health and has about 2% for improving their lot.

@Ash to put numbers behind it: it took from 600 years to get from about 45 to 90 million people in Europe. That means it took about 600 years to double the crop yield of the farmers from post antiquity to high medieval. Before that, there were 900 years of pretty much no change - the census under Augustus and the estimated numbers for the year 900 are pretty close. Assume that the number of people on the scale is the number of people that can be supplied, and then look at the far left in the stone age: commons.wikimedia.org/wiki/…

@Trish We don't need to make the same mistakes twice, or learn the same thing twice. We've learnt every lesson in history already before (As handwaved in the question). No-ones going to farm using the methods of antiquity while looking at the nearby hills they know have a high likelyhood of copper deposits, knowing how to make better tools using copperworking techniques, and go "Meh - I better wait 900 years to do that." You'll use any spare time you have to make your life better, and knowing all the tricks, you'll get there pretty quickly.

@Ash the problem is, that it takes tools to make better tools. Without any tools, you have to start with nothing. To do agriculture, you need a tool you can't rush: Domesticated crops. It took 26 dynasties for Egypt to get enough of a grain and food industry to support 20,000 settlements and towns with a total of 7-ish million people. About 4000 BC, the estimated population of all of Egypt could support was 350,000 - a third of the group! It took about 1000 years (33 generations) to support 870,000!

@Ash the key limiting factor is the need to domesticate food crops and turn land into farms. And they start without any of either.

Mine Iron first, it is a lot easier to find and not that difficult to smelt. Copper is fairly rare on the earths surface, better to wait until they find a good ore deposit.

@John and your people are starved...

@Trish this depends a lot on how productive the land is, some Native Americans supported massive food surpluses because they lives in unbelievably fertile areas. North west coast potlatch societies. Keep in mind you can do two things at once, most of that first week is going to be spent building tools to help collect food efficiently (nets baskets, hoes, spears, ect.) while collected low hanging fruit so to speak.

Keep in mind that hunter gatherer society tend to be quite small, so you'll need to split your 1M people into thousands of clans, spread over a large geographic area. Not all resources will be available everywhere, so long-distance trading will be needed. Tasks also become more difficult with fewer people - ten thousand clans of 100 people each, each of which devotes 5% of the population to a task is still just doing the same task in parallel ten thousand times. This won't go nearly as fast as just applying 5% of a unified 1M to a single project.

Basically, until you achieve food production that can support a dense population, you don't really have 1M working up the tech tree together, you have many groups of ~100 people each, each of which has to solve the exact same set of problems in parallel with one another. You don't get any economy of scale, as every clan has to build a kiln for its own people - you can't just build one kiln and have everyone use it. Until you get agriculture, the question is really how fast can a group of ~100 individuals advance, as there's no way to get 1M people physically near enough to count as one group.

@NuclearWang I estimated that after approximately year 9-13 you could merge them back into small towns, although there will be some trade before that to make up for differences in relative stock, and some of those farming communities will be still farming and shipping food into the towns.

This seems to assume that knowledge grants competence, which isn't stated in the question, and is not a reasonable assumption IMO. It doesn't take into account the huge amount of time and resources that must be spent to learn the craft. Unless these people are already seasoned artisans, any crafts they attempt will be dismal failures at first. Knowing how to weave a basket from reeds doesn't mean you can immediately produce excellent quality baskets. Both time and resources are needed for practice, and both will be in short supply for a long time.

This is FAR to optimistic. There's a big difference between first achieving something, and then mass producing it. For example, the first steam engine doesn't mean steam engines will then become common place. With primitive technology it'd take months to just make one. A lot of other technology would require steam technology to be common, and more evolved than the first prototype. Same with all the following technology. A civilization wouldn't come close to creating rockets in 70 years.

In defence of this answer - there has been a LOT (and I mean a LOT LOT) resources and effort wasted in the past (e.g. in the early medieval European example) on wars, luxuries for nobility, etc. Without any armour, weapons (besides for hunting), fortifications, gold/silver/gem mining, making jewellery, hunting for and preparing furs, etc., you can focus on feeding people. Think of all those young men which were fed and trained for a decade and then died needlessly. It might be too optimistic, but not outrageously so.

In additional defense of this answer, there are a lot of things that didn't get invented until relatively recently that could have easily been done thousands of years prior. The mould-board plough for example wasn't invented until the 18th century, but it only needs some rather basic woodworking and primitive metalworking that were available in many parts of the world before the 11th century, and in some places even before the 1st century CE.

That said, I still think this answer is too optimistic, but not by anywhere near the degree that many others seem to. A lot of technological development historically has been limited not by what we can do, but what we know.

@BIOStheZerg It overestimates the capabilities of subsistence farming on non domesticated crops. Our modern wheats stem from Triticum boeoticum Boiss. One of the oldest stems that still planetd one is "Einkorn", which was domesticated beween 8000 BC and 6000 BC. However, a modern Einkorn is still about several times more productive than original ones.

@AustinHemmelgarn the main bottleneck of the civilisation is food. To support any industry beyond the manufacturing of tools for the cultivation of food, you need at least the production of middle-yield crops. Emmer and Einkorn are among those starters that are needed to get agriculture going, and even then you need to spend about a decade to just multiply the found crops to an amount to do actual agriculture: a single stem of einkorn wheat only produces few seeds compared with modern wheat

Einkorn can, with fertilizer and modern equipment, yield up to 1600 pounds per acre, but you need 70-100 pounds to seed a single acre. That's a factor of about 16 times the input. So if you start with about one pound of einkorn gathered, and only can manage one harvest a year, it takes 7 harvests to get the seeds for acre, ignoring any misharvest. Year 8 is 16 acres, year 9 256 acres.

eh... wait, borked my math I think

ok, 2nd harvest yields enough for 2.5 acres. it takes 9 harvests to seed the 25000 acres of 4000 BC Egypt. So about one decade to even be able to get any bread

@Trish I'm not disputing food as a limiting factor, that's most of why I consider the answer overly optimistic in fact. Some of the comments here seem to be assuming that middle-ages level technology is impossible without middle-ages level infrastructure, which is quite simply wrong (it's harder, and you won't have mass production, but you can make a lot of middle-ages tech-level items with iron-age infrastructure if you simply have the knowledge of it).

Getting past that first decade or so to get working agriculture is the primary issue here, not tech availability.

I work on the assumption that without ANY infrastructure, you need to build up the needed tools. Remember that you lose most of your population in the initial month from hunger as there is no way to support them in any way without tools, which means you lose their workforce. Those 1-million can'T even hunt down all the son as they don't even have the means to make a simple bow.

@AustinHemmelgarn the first decade is entirely hunter-gatherer and you may not eat any of your grain yield or that decade.

if you'd eat half your yield or that part goes bad, you'd need at least 13 harvests to even seed the 25000 acres needed. ok, you also need to make those 25000 acres arable, but if we talk nile here, the river does that for us.

if OP had given our people the headstart of starting them off with modern wheat to sow one acre, the whole situation would be MUCH less bleak.

@Trish Noone disagrees that food will be a great limiting factor in the first years, and that quite possibly the first year or two will be all about survival and many (most?) won't make it. But at the same time, your 9/13 harvests were based on 1lb of corn. Let's say that a "clan" of 100 people would spend 1% of their gathered seeds on planting (and 99% on survival), you've the ENTIRE produce of one person being poured in - possibly hundreds lb. Also, note multiple seasons/year in some areas.

@Trish I doubt a HUGE number of people would die from hunger in the beginning. A good example is the native peoples in the Americas; without modern hunting, there'd still be considerable amounts of things to hunt in this land, and when they first arrive there would be a lot of berries and easily available food like that

There would probably be enough berries and easily available food for the first week or so, and by then they'd have fire and sharp sticks. It wouldn't be too hard to set up some traps for rabbits, giving them a fair amount of easily available meat in the first few weeks.

Additionally, I'd be surprised if this didn't change one you use other staple foods, such as potatoes or the queen of nutrition - the sweet potato. You WOULD want some cereals for their good shelf life, but I wouldn't make it the only/main staple. Another thing to consider is that the combined human knowledge would allow you to use (for food or otherwise) a much larger part of wildlife than any real gatherer ever could.

After the first few weeks, that gives them a little while to get better hunting techniques, and they could use the rabbit skins to make slings. Once they can get larger animals like deer, they could last for months by traveling around. This gives them time to start on agriculture, as well as technology like bows for hunting bison or other similar large animals that would feed a lot of people and give lots of skin.

I think rockets and modern hospitals is a little unrealistic, but I see no major issue that would prevent them from reaching industrial revolution level technology, maybe with more of a focus on ranching rather than crops for agriculture.

While they may not be able to grow wheat effectively, there are a lot of other options for farming. Corn, beans, squash, fish, rabbits, maybe not any larger animals because they wouldn't be domesticated.

I believe the answer is over-optimistic but food or predators aren't the worst bottleneck - it's the labor to build all the buildings you need. E.g. a simple brickyard is pretty easy, but it will eat a lot of manual labor to keep it running; automation is always possible, but that takes even more manual labor.

What buildings do you need? Skin teepees would work until the industrial revolution.

Also, we can start using the assembly line way earlier than ever possible. With modern project management and that sort of thing, I'd expect most jobs to go a lot faster, regardless of what they are.