Changes

{{cquote|Our theory of evolution has become, as Popper described, one which cannot be refuted by any possible observations. Every conceivable observation can be fitted into it. It is thus outside of empirical science but not necessarily false. No one can think of ways in which to test it. Ideas, either without basis or based on a few laboratory experiments carried out in extremely simplified systems, have become part of an evolutionary dogma accepted by most of us as part of our training. The cure seems to us not to be a discarding of the modern synthesis of evolutionary theory, but more skepticism about many of its tenets.<ref>L.C. Birch and P.R. Ehrlich, Nature, vol. 214 (1967), p. 349</ref>}}

{{cquote|Our theory of evolution has become, as Popper described, one which cannot be refuted by any possible observations. Every conceivable observation can be fitted into it. It is thus outside of empirical science but not necessarily false. No one can think of ways in which to test it. Ideas, either without basis or based on a few laboratory experiments carried out in extremely simplified systems, have become part of an evolutionary dogma accepted by most of us as part of our training. The cure seems to us not to be a discarding of the modern synthesis of evolutionary theory, but more skepticism about many of its tenets.<ref>L.C. Birch and P.R. Ehrlich, Nature, vol. 214 (1967), p. 349</ref>}}

=== Universal Laws ===

=== Universal laws ===

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".