I've never had formal training in logic. Neither have I. > I assume you have proof you exist. You assume incorrectly. I have a tonne of evidence for my existence though. > If the appple falls on your head do you assume gravity, or simmply propose the theoretical existence of a gravitional force? If an apple falls it evidence for: a force curved space time god take your pick David. > This is not a facetious comment. I am trying to define how you accept proof in science. In science I don't accept proof; I accept evidence. Science does not reach the truth. I have been saying this all along.