Thousands, perhaps millions (or perhaps billions, or trillions — but bear with me) there was an ancient civilizations. It has achieved things we can only dream about (faster-than-light travel, powerful magic, social utopia) but for some reason (internal conflict, strange disease, raiders from outer space) it has fallen down. Today, sifting through the ruins of this once-great empire, we can advance our science a hundred-fold with no original research — just an attempt to understand what our ancestors had.
This is the premise of countless fantasy and (though less universally) science fiction worlds. The sifting-through-the-ruins for science-and-technology-we-can-hardly-imagine is a classical trope. Stargate managed to build a whole franchise out of it, but the dreams of an early, forgotten, stage of glory that we can recapture merely by being diligient enough in sifting through the archeological ruins is a classic everywhere.
How comes it makes sense? If we compare the world we grew up with the ones our parents grew up in, or our grandparents (or, alternatively, the one in which it seems our children will grow up in), it seems to be moving in one direction: progress relentlessly marching on. Perhaps it marches on some luddites’ toes, but it marches on towards more science, more technology. And yet, the premise of the once-ancient civilizations which is thousands of years ahead of us seems eminently plausible.
I suggest that like many things, it is based on something very real. There was exactly one period during history in which that was eminently true — the Renaissance. After the dark ages, which followed the Roman empire, suddenly it was OK again to delve into knowledge. The Romans had writings and plans that far preceded the people of that time. Indeed, much of the scientific advances at that period were merely attempts to rediscover what the Romans already knew. It was certainly an exciting time to be a scientist — just learning what the Romans had could fill one’s lives. Worst of all — this was when the modern notion of science and technology started. And so, the birth of modern science was shrouded in the mystique of rediscovering an early civilization. Like any formative experience at an early age, it set the tone for the rest of science’s life — and was given free reign in science-fiction, where we could exaggerate the Romans into “Atlantis” and its counterparts, where we could know all the universe’s knowledge, if we but decipher the ancient writings.