482 ON SPECIES 



truths, why there is an end of the whole matter, and it is 

 no use hoping ever to get to any rational explanation of 

 origin or dispersion of species so I hate them. 



January 6, 1859. 



I am determined to start in my investigations on a 

 different principle and to try and square all my facts with 

 (or arrange them by) the most modern doctrines without 

 therefore adhering to or accepting those doctrines. The 

 old theory of absolute creations, of single individuals or pairs 

 is used up ! Grant them, and what's the use of arguing any 

 more ? Grant too that all migration has been effected under 

 existing relations of sea and land, and there is an end of 

 that matter, we may whistle for another force to effect 

 migration, other than the known agency of animals, winds, 

 and waters. If we are to assume nothing but these, we are 

 stumped ! If the course of migration does not agree with 

 that of birds, winds, currents, &c., so much the worse for 

 the facts of migration ! No religious creed could be more 

 exigent, exclusive, and repressive. I should be wrong to 

 say I disbelieve these doctrines simply because they do not 

 explain my facts, so long as they do not contradict them. 

 I should be as wrong to say that I believe them so long as I 

 think that other doctrines may explain the facts as well or 

 better than these. I now then start on the assumptions : 

 (1) That all vegetable forms are in a state of unstable equili- 

 brium. (2) That the rate of change and extent of change 

 vary at different times and places, depending on physical 

 conditions, i.e. on extent of surface to change over and of 

 conditions of surface to promote and perpetuate change. 

 (3) That the majority of main types of existing forms have 

 survived all Geological changes from the Palaeozoic era 

 downwards to our time. (4) That during this interval 

 many of these type forms have migrated from one hemisphere 

 to another, some of them remaining specifically unchanged, 

 others generically, others subordinately. (5) That during 

 their migration they have expanded and contracted, i.e. 

 sometimes thrown off constellations of varieties that (by 

 selection) have become new species, at others few, at others 

 none. (6) That during some epoch there has been any 

 amount of change of land and water. 



This does not touch the aboriginal condition of all 



