I had also, during many years, followed a golden rule, namely that whenever published fact, a new observation of thought came across me, which was op… - Charles Darwin

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. Here then I had at last got a theory by which to work; but I was so anxious to avoid prejudice, that I determined not for some time to write even the briefest sketch of it. In June 1842 I first allowed myself the satisfaction of writing a very brief abstract of my theory in pencil in 35 pages; and this was enlarged during the summer of 1844 into one of 230 pages...

It is not the strongest of the species that survives,
not the most intelligent that survives.
It is the one that is the most adaptable to change.

What wretched doings come from the ardor of fame; the love of truth alone would never make one man attack another bitterly.