* 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.