The falsifiability criterion arose as a result of Popper's analysis of the logic of universal laws. Universal laws have a logical structure which precludes certain existential statements : universal laws are a negation of an existential proposition. Popper's example was that of the color of swans. The universal statement "all swans are white" implies the negative existential statement "no swans of a color other than white exist". To verify the negative existential we would need to trawl through the universe to ensure that no non-white swan existed anywhere in time or space. Conversely, if we saw just one black swan we could confirm the existential statement "black swans exist" and refute the universal "all swans are white". | The falsifiability criterion arose as a result of Popper's analysis of the logic of universal laws. Universal laws have a logical structure which precludes certain existential statements : universal laws are a negation of an existential proposition. Popper's example was that of the color of swans. The universal statement "all swans are white" implies the negative existential statement "no swans of a color other than white exist". To verify the negative existential we would need to trawl through the universe to ensure that no non-white swan existed anywhere in time or space. Conversely, if we saw just one black swan we could confirm the existential statement "black swans exist" and refute the universal "all swans are white". |