The use and abuse of Sir Karl Popper

Karl Popper has been one of the few philosophers of sciences who has influe nced scientists. I evaluate Popper's influence on our understanding of evol utionary theory from his earliest publications to the present. Popper concl uded that three sorts of statements in evolutionary biology are not genuine laws of nature. I take him to be right on this score. Popper's later disti nction between evolutionary theory as a metaphysical research program and a s a scientific theory led more than one scientist to misunderstand his posi tion on evolutionary theory as a scientific theory. In his later work Poppe r also introduced what he took to be "improvements'' of evolutionary theory . Thus far these improvements have had almost no influence on evolutionary biology. I conclude by examining the influence of Popper on the reception o f cladistic analysis.