Byrd_Hunter, you rightly add your speed sign example to demonstrate there are challenges of context, perception, and interpretation on the path to truth. The practices of science include studying exactly such things and figuring out ways to correct for them, such as having people all around the world with and without different world views, schools, cultures, religions, mores, etcetera, duplicate experiments to see if results can be confirmed or not.

If they are repeatedly confirmed, then those things are provisionally accepted as true enough on which to base further experiments seeking further truths.

Taking scientifically verifiable truths and using them to guide actions in the world is often controversial, especially when they seem to contradict a given world view, school of thought, culture, religion, set of mores, etcetera. Over time it appears that regardless of the popularity of a given world view, school of thought, culture, religion, set of mores, etcetera, if science demonstrates the world is not flat enough times, the truth-seeking power of science prevails.