There is an RPG system called GURPS, many of you probably know it. In this system, there are tech levels:
GURPS Tech Levels
TL0: Stone Age
TL1: Bronze Age (3500 BCE+)
TL2: Iron Age (1200 BCE+)
TL3: Medieval (600+)
TL4: Age of Sail (1450+)
TL5: Industrial Revolution (1730+)
TL6: Mechanized Age (1880+)
TL7: Nuclear Age (1940+)
TL8: Digital Age (1980+)
TL9: Microtech Age (2025+)
TL10: Robotic Age (2070+)
TL11: Age of Exotic Matter
TL12: Age of Miracles
TL^: Superscience Tech
Before you guys start throwing Atomic Rockets articles at me saying that tech levels are bad and tech trees are superior (Atomic Rockets is an excellent website, by the way, check it out: http://www.projectrho.com/public_html/rocket/), listen what I have to say.
Firstly, it is important to note that, by the time Thrive is complete, humanity is probably going to be at TL9 (the Microtech Age). This means that TL13 will not longer be Superscience Tech, we will already have enough knowledge to visualize it. So, moving forward, most people say that, in Thrive, the Space Stage will start as hard science fiction, and then gradually become softer. This is okay, but when will it happen? The answer is: when we reach TL14. When we reach this milestone, Superscience Tech will be available, such as FTL travel. Many possibilities will start to appear after that.
Now, let’s talk about tech trees. There will obviously be tech trees, they are much more realistic than tech levels (see http://www.projectrho.com/public_html/rocket/techlevel.php). But will we need to throw away everything I just said? Not necessarily. What if we mixed both systems? Like, classifying different types of technology as belonging to a certain tech level, but still allowing, e.g., [mostly] TL9 civilizations to have some TL10 technologies. Here is some example of the tech levels of different technological paths:
Divergent Tech Levels
Steampunk: TL6+
Teslapunk: TL7+
Dieselpunk: TL7+
Atomicpunk: TL8+
Cyberpunk: TL8+
Biopunk: TL9+
Solarpunk: TL9+
Nanopunk: TL9+
A civilization’s TL would be determined by the average of its technologies’ TLs, where more advanced technologies have a greater weight. So, it’s basically that. Thoughts?
Note: there are some superscience technologies that would be available before TL^. They would be harder to be developed, though.