Your comment about the tribesman reminds me of this essay by Isaac Asimov: http://chem.tufts.edu/answersinscience/relativityofwrong.htm http://chem.tufts.edu/an

Your comment about the tribesman reminds me of this essay by Isaac Asimov: http://chem.tufts.edu/answersinscience/relativityofwrong.htm http://chem.tufts.edu/answersinscience/relativityofwrong.htm He makes the great point that the tribesman isn't too far off from the truth: The earth is flat if its curvature is zero, but the 'truth' is that the curvature is almost zero(and the difference isn't measurable by a tribesman).