With threats such as resource exhaustion and global warming facing humanity there is a non zero chance that our modern civilization will not last the distance, and may in fact collapse. It would of course not be the first time a civilization collapsed. Other civilizations have collapsed before, perhaps the best example being to Roman Empire. So would a collapse be so bad? Assuming we manage to protect the knowledge we have discovered could we not simply rebuild our machines some time later once we recover?
Our current technology has taken time to develop, evolving over time in the context of the existing society. But if you put a group of computer makers in the middle of Africa and ask them to make a computer what would you get? To begin with they are going to need raw materials such as metals, plastics, rare earth metals, and various synthetic chemicals. When our civilization began metals were relatively easy to find, essentially being on or near the surface. Today all those easy to access sources of metal have been exhausted. Similarly the ability to make plastics will be limited by the availability of petrochemicals. Again all the oil has already been extracted from sources that are easily accessed. The only way we can get to the ever more remote resources today is with our technology. Drilling for oil in thousands of feet of ocean simply isn’t possible without advanced technology. Mining to extract metals today requires technology.
This means that any subsequent civilization will not have access to the same easy to access to resources. The development of our current technological world is essentially on the back of easily accessed resources. Without plentiful sources of energy to power our machines we would not have seen such a rapid development of technology. Our civilization is now dependent on the steady supply of finite resources. Products such as computers are amazingly cheap because all the infrastructure from mines to silicon fabrication plants are in place. To create that infrastructure has required a whole technological civilization. So, to answer the question about the computer makers – they would need a technological civilization to make a computer.
One could almost apply the irreducible complexity argument for our current civilization, as taking away one critical aspect would have flow on impacts to the others. Take away oil and you cannot make plastics. No plastics means no computers. No computers means no communications. We have historical records for the development of our technological society, so we know that our current technology didn’t jump fully formed into existence. Invention, even when performed by intelligent species such as ours is a evolutionary process of building on ideas.
If there is a collapse there will be a bootstrap problem that our ancestors did not deal with; a lack of easily available resources. Without these resources it may not be possible to build the technology. It is like knocking away the ladder; what was once easy would be much harder or perhaps impossible, even with a complete understanding of modern technology.
Could it be any other way? One solution would be to expand. There is a whole universe out there just waiting for a upstart species like us to take advantage of it. While the resources on earth are limited the resources in the wider universe are functionally limitless. By getting off planet and expanding we are spreading the risk; a disaster or collapse on Earth will no longer mean the collapse of our technological species. In fact if we could exploit the wider solar system we could perhaps avoid resource exhaustion here. Again, it is important to understand that this is option is foreclosed when civilization collapses.
Another solution would be to focus on technology development that uses resources that will certainly be available; solar power, hydro power, wind power, wood, natural fibres and plastics manufactured from synthetic hydrocarbons. We might also think about developing small run personal manufacturing. The increasing popularity of 3D printing may be in the early days but potentially this kind of technology will also mitigate the risk of lost manufacturing facilities.