From Darwin's own thoughts. Part III.

This is the third installment of my annotated selection of pithy quotes from Darwin's autobiography (my comments in blue):

Darwin and Wallace both felt inspiration, or a vital explanatory link, in Thomas Malthus' book:
"In October 1838, that is, fifteen months after I had begun my systematic enquiry, I happened to read for amusement 'Malthus on Population,' and being well prepared to appreciate the struggle for existence which everywhere goes on from long-continued observation of the habits of animals and plants, it at once struck me that under these circumstances favourable variations would tend to be preserved, and unfavourable ones to be destroyed. The result of this would be the formation of new species."

Darwin's reflections on his theory of evolution and his most important work:
"The solution, as I believe, is that the modified offspring of all dominant and increasing forms tend to become adapted to many and highly diversified places in the economy of nature."

"This shows how necessary it is that any new view should be explained at considerable length in order to arouse public attention."

"Though considerably added to and corrected in the later editions, it has remained substantially the same book....It is no doubt the chief work of my life."

"It has sometimes been said that the success of the 'Origin' proved "that the subject was in the air," or "that men's minds were prepared for it." I do not think that this is strictly true, for I occasionally sounded not a few naturalists, and never happened to come across a single one who seemed to doubt about the permanence of species."

Darwin was most elaborating and saw deeply, but actually, there were ideas floating around, as Wallace (but also others, too) proves.  This undoubtedly affects ideas we think about today, too, but we can find our like-thinking contemporaries--or predecessors--by web-searching (if we want to).

"Another element in the success of the book was its moderate size; and this I owe to the appearance of Mr. Wallace's essay; had I published on the scale in which I began to write in 1856, the book would have been four or five times as large as the 'Origin,' and very few would have had the patience to read it.

I cared very little whether men attributed most originality to me or Wallace; and his essay no doubt aided in the reception of the theory."

Darwin, ever the generous man.  But his societal advantages guaranteed his preeminence, and he was more thorough.  Wallace's ideas were more group- than individual-oriented, and may have some merit although Darwinites take pleasure in scorning them.  And nobody can refer to most of Darwin's books as other than quite long!

"Hardly any point gave me so much satisfaction when I was at work on the 'Origin,' as the explanation of the wide difference in many classes between the embryo and the adult animal, and of the close resemblance of the embryos within the same class. No notice of this point was taken, as far as I remember, in the early reviews of the 'Origin,' and I recollect expressing my surprise on this head in a letter to Asa Gray.

Darwin relied on embryological data and ideas from his predecessors, particularly von Baer  in Germany.

"Towards the end of the work I give my well-abused hypothesis of Pangenesis. An unverified hypothesis is of little or no value; but if anyone should hereafter be led to make observations by which some such hypothesis could be established, I shall have done good service, as an astonishing number of isolated facts can be thus connected together and rendered intelligible."

Darwin is right about his idea of Pangenesis (the idea that each part of the body emits particles that he called 'gemmules' that congregate in the gonads and contribute to the gametes) being of 'little or no value', and indeed it was very much like the Lamarckian view he sneered at.  But what is the role for free speculation in science?  Darwin's speculating was pretty clear, since there was no data supporting 'gemmules' or 'pangenesis'.  Yet, as long as they are clearly  marked as guessing, can intelligent guessing stimulate creative thought?  Is it better, or worse, than just saying "we have no idea how this works...."?