The most important discoveries are those that change how we see the world.
For example "Clan of the Cave Bear..." The heroine Ayla uses bow and arrow to stop a Neanderthal, before he can get close enough to use a thrusting spear. That shocks his tribe.
At that level, we might include fire, and wheel. Perhaps steam engine.
But then the gas engine is a refinement, not a paradigm shift.
The most important discoveries are those that change how we see the world.
For example "Clan of the Cave Bear..." The heroine Ayla uses bow and arrow to stop a Neanderthal, before he can get close enough to use a thrusting spear. That shocks his tribe.
At that level, we might include fire, and wheel. Perhaps steam engine.
But then the gas engine is a refinement, not a paradigm shift.