Our Knowledge and the Earth as a Point

One thought that I had as I read Ptolemy relates to our own modern theories of the universe and science in general. For us reading Ptolemy's arguments that the Earth does not move--arguments such as "all objects not actually standing on the earth would appear to have the same motion, opposite that of the earth" (62)--these arguments and their results and implications seem absurd. Yet Ptolemy and others were so convinced by them. It just makes me wonder about the security of our own theories. We are so convinced by them, but perhaps 2000 years from now, people will look back on them as absurd. Can we find any assurance that our "scientific knowledge" is accurate, that is, that it reflects reality or "the way things really are"?

On another note, building off Mike's post a bit, I thought it was interesting that Ptolemy had a sense that the earth was only as a point in relation to the rest of the universe. On page 61, he says, "this great bulk of earth, when compared to the whole surrounding mass [of the universe], has the ratio of a point to it." Ptolemy, however, seems undaunted by this idea. Perhaps this is because he still believed the earth had a very specific and significant place in the universe, even if it was a very physically small one.