How as an individual can I know if the Earth is a sphere or a flat disc? What experiment can I do that doesn't involve trusting information from a 3rd party that would prove what the geometry really is?
http://i.imgur.com/O8IpMmi.jpgGo up to 35,000 Ft on a flight around the world and you can see for yourself it's NOT flat
The passenger windows on commercial airlines are curved and cause barrel distortion in the image a passenger sees. The pilot has flat plane windows and he sees a perfectly flat horizon.
