Imagine a person in the ancient world who came up with the following idea: "What would the sun and moon look like if they were very very far away?" This idea would likely lead to the conclusion that they would look like tiny points of light, which then could lead to the question "What if the tiny points of light we call stars and planets are actually faraway suns and moons?"
Unfortunately, our ancient friend would likely be stuck at that point, due to the limitations of human vision and the lack of proper instruments for examining the nature of celestial objects. But our friend would be right, unlike nearly every other human until Giordano Bruno's cosmology of 1584.
My questions then are, what other ideas of similar power exist, how will we know them if we find them, and is there any way to search for them intentionally?