CH. XIV] GENERAL DISCUSSION 175 



the absence of adaptational reasons for progress, and with the 

 frequent impossibiUty of transitions (especially in the characters 

 of the higher groups) it seemed to be almost the only way. 



My friend Dr H. B. Guppy was perhaps the first to call proper 

 attention to the fact that the Darwinian theory was trying to 

 work evolution backwards. He says (12): "It follows from the 

 foregoing remarks that no plant groups, in the sense of the great 

 orders, could have been produced on the evolutionary lines im- 

 plied in the Darwinian theory" (i.e. beginning with small 

 varieties and going through species to genera and families), and 

 continues "to lay down, as the Darwinian evolutionist does, that 

 the order of development begins with the variety . . . species . . . 

 genera. . .families, is to reverse the method followed in nature, 

 since it implies that the simpler, least mutable, and less adaptive 

 characters that distinguish the great families are the last de- 

 veloped. This could never have been. Nature has ever worked 

 from the simple to the complex, from the general to the particular. 

 Had she followed the lines laid down by the Darwinian school 

 of evolutionists, there would be no systematic botany. All would 

 be confusion. There would be no distribution in the sense in which 

 the term is generally understood, and the plant world would be 

 a world of oddities and monstrosities." 



It is upon such propositions and facts that the pre-Darwinian 

 theory of differentiation or divergent mutation is now founded. 

 Natural selection is no longer to be regarded as the mechanism of 

 evolution; it does not choose what shall be evolved, but it decides 

 in each case, individually , what shall be allowed to live. Probably 

 the bulk of the structural characters make little or no difference 

 one way or the other, and so are indifferent to natural selection. 

 Evolution ceases to be a mere matter of chance, and comes into 

 that scheme of things of which Jeans has said that all the 

 pictures which science draws of it are mathematical pictures. 

 What causes it to go on we have yet to discover, but we can make 

 one important step by finding out in which direction evolution 

 moved, for that involved in the theory of differentiation is the 

 exact opposite of that involved by natural selection. One goes 

 from the family downwards, the other from the variety up, and 

 as there is as yet no evidence to show that it moved in one 

 particular direction, we are free to take that for which there is 

 the better evidence. 



After fifty years of work, the author has come to the conclusion 

 that evolution and natural selection work at right angles to one 



