  But it is here that even the most sympathetic of Darwin’s theistic supporters were forced to qualify their support for the theory of descent with modification by means of natural selection.  In Darwin’s day the reactions of Asa Gray and John Herschel are perhaps the most interesting in this respect.  Both men saw in Darwin’s theory a way to account for ‘that mystery of mysteries,’ the regular appearance of new species by means of natural, or as they might say, ‘intermediate’ causes.  However both instinctively recoiled from the irreducible and central role of ‘chance’ in the theory.  They did not, but easily could have, said ‘God does not play dice with the universe.’ But as Darwin stated repeatedly, if gently, to Gray—if God ordained that variations should be along beneficial lines, natural selection would be redundant. Moreover, the evidence from the study of variation in domestic and natural populations put the lie to any claim that God directs all or most variation along beneficial lines. Darwinian selection theory is a two-step process—the production of variation unrelated to the adaptive requirements of the organism, and differential perpetuation of those variations that serve adaptive needs. Again, a theory of evolution that could not be so described would not be a Darwinian theory.