A parable, on how to ascertain what may not be plain.
Once upon a time there was a group of intelligent people who were cut off from the accumulation of human knowledge. So they were left behind the technological advances of human civilization, as sometimes happens. They generally lived together well enough, decently, as such is not an issue of technology.
Then one day a man saw a plane fly over their jungle and brought back the story to the village. Because he was known to be trustworthy the people believed his witness, the story of such a strange phenomena excited them and inspired a search for answers. Eventually a man and a woman in the community had their role come to be trying to figure out what it had been, among other things having to do with knowledge.
The man said, "We know natural things like birds, trees and flowers. This is all we observe. This is all we can test. So a natural explanation is all we can allow ourselves. So I think it was just a type of bird, like what we know."
"I do not believe that was a type of bird." replied the woman. "We can also observe that we can make things. If there was a race of humans or other beings that had a sort of intelligence similar to our own then there is no telling what they could make. I think that was something made by a civilization far, far in advance of our own."
"Well, I saw a bird fly the other day. So it obviously doesn't take any technology to fly."
"Are you sure?" replied the woman.
"Hmmm, what is technology, anyway?"
"It would seem that it is just the practical application of knowledge."
Then the man said, "Oh....this is probably going to keep us thinking for a while."
The woman replied, "Yes....thinking, well, that will probably keep us out of trouble."
So they kept thinking about the story of the plane and in so doing they began to accumulate knowledge, which kept them out of trouble.