What does it mean to "know?"
Oxford English Dictionary
"True, justified belief; certain understanding, as opposed to opinion."
Every day when students come to school, they are taught lessons from history, science, math and language. How, though, does a student know that what they are being taught is true? When they are taught about human rights crises in Syria, how do they know that those things are actually happening? How about whether history actually happened? That there is no gravity in space? In essence, what does it mean to “know” something?
For countless people from different civilizations, beliefs and eras of time, they would look up to the sky and see objects moving around them, lending credence to a self-important view as being the focal point of all things. The sun rose in the east and it set in the west. Constellations appeared at different times in the year to tell us of impending seasons and related phenomena. Human beings were held above all things on earth and were subject only to the great power of the heavens, which was focused down upon us.
What evidence can we point to in order to say that the sun isn’t moving from one part of the sky to another? At the time of Nicolaus Copernicus, there was a millennia old Ptolemaic view of a geocentric universe placing the earth at the center. What needed to be done to prove that the earth moves? What obstacles exist that prevent an earth shattering change to people’s worldview?