One of those subjects on which Darwinists are at a complete impasse is the origin of mammals. Evolutionists cannot offer any evidence for the origin of mammals and the supposed evolutionary family relationships between the animals in this class. Statements by George Gaylord Simpson, one of the 20th century’s leading evolutionists, show the great predicament facing the theory of evolution is: "This is true of all thirty-two orders of mammals ... The earliest and [supposedly] most primitive known members of every order already have the basic ordinal characters, and in no case is an approximately continuous sequence from one order to another known. In most cases the break is so sharp and the gap so large that the origin of the order is speculative and much disputed ..." (George G. Simpson, Tempo and Mode in Evolution, New York: Columbia University Press, 1944, pp. 105, 107)