Just to clarify, you realize that archimedes designed mirrors that did take down Roman warships in the siege, and it was discounted because idiots until recently “couldn’t imagine it”.

And that is entirely my point: you are acting like their ability to understand is less because they’re from a different time.

Sure such an individual would need a primer, but their capacity to understand is still there. They’re at least as smart as we are today; which just have a leg up based entirely on their work.

If you went to newton and explained a rocket (that uses Newtonian physics to him,) he would be like “that’s cool”;

If you went to DaVinci and explained that his work in automation (the automaton knight,) would one day lead to the Boston dynamics robot, he might be scared of it, but he’d believe it.

If you went to Charles Babbage and explained that his Difference engine and analytical engine would one day lead to the modern internet; he might be disappointed with what we’ve done with it; it he would recognize it’s all just math, that his machine was as capable even if it would take it longer.

Like us, there was a broad range in individual capacity. And there will always be. But, all of this is quite besides the point: there are things that we can definitively say don’t exist. In order to build something that truly is FTL; we would have to literally rewrite and forget our modern understanding of physics.

There are ways around it- traversing a wormhole would technically not be. There is no handwavium that would allow aliens to get here by a process we cannot understand or guess at. Without a primer, it might take us a while poking and prodding, it we have the capacity to understand it.

Which is the single best argument for why aliens have not visited. Because there’s a non-zero chance that we’d turn into genocidal xenophobes and use their technology to blow up entire planets.

Hell, we have politicians that are scared of human immigrants; wanting to send the army in to stop refugees.