The Main Conclusion Arrived At In This

... Probably All The Organic Beings Which Have Ever Lived On This Earth Have Descended From Some One Primordial Form, Into Which Life Was First Breathed.

Although I Am Fully Convinced Of The Truth Of The Views Given In This Volume Under The Form Of An Abstract, I By No Means Expect To Convince Experienced Naturalists Whose Minds Are Stocked With A Multitude Of Facts All Viewed, During A Long Course Of Years, From A Point Of View Directly Opposite To Mine... I Look With Confidence To The Future, To Young And Rising Naturalists, Who Will Be Able To View Both Sides Of The Question With Impartiality.

I Always Feel As If My Books Came Half Out Of Lyell's Brain... & Therefore That When Seeing A Thing Never Seen By Lyell, One Yet Saw It Partially Through His Eyes.

At Last Gleams Of Light Have Come, And I Am Almost Convinced (quite Contrary To Opinion I Started With) That Species Are Not (it Is Like Confessing A Murder) Immutable. Heaven Forfend Me From Lamarck Nonsense Of A 'tendency To Progression', 'adaptations From The Slow Willing Of Animals', &c! But The Conclusions I Am Led To Are Not Widely Different From His; Though The Means Of Change Are Wholly So. I Think I Have Found Out (here's Presumption!) The Simple Way By Which Species Become Exquisitely Adapted To Various Ends.

Progress Has Been Much More General Than Retrogression