Stephen Jay Gould Evolution is a theory It is also a fact Neil Campbell Today nearly all biologists acknowledge that evolution is a fact The term theory is no longer appropriate Ernst Mayr The basic theory of evolution has been confirmed so completely that most modern biologists consider evolution simply a fact And evolutionary change is also simply a fact Richard Lenski Evolution is both a fact and a theory Carl Sagan Evolution is a fact not a theory George Simpson Darwin finally and definitely established evolution as a fact R C Lewontin evolution is a fact not theory Douglas Futuyama the historical reality of evolutionis not a theory It is a fact H J Muller evolution is not a fact or rather that it is no more a fact than that you are hearing or reading these words Kenneth R Miller evolution is as much a fact as anything we know in science