Charles Darwin was an unusual scientist. For Darwin,
science was obviously not a 'profession.'... It was a necessity to sustain his mind, just as the food he ate and the air he breathed....
Theodosius Dobzhansky (From Barrett, Paul, ed The Collected Papers of Charles Darwin [Chicago: University of Chicago Press, 1977] p. xiii)
Reflect on this quote from Charles Darwin:
From my early youth I have had the strongest desire to understand or explain whatever I observed -- that is, to group all facts under some general laws. These causes combined have given me the patience to reflect or ponder for any number of years over any unexplained problem.... I have steadily endeavoured to keep my mind free, so as to give up any hypothesis, however much beloved (and I cannot resist forming one on every subject), as soon as facts are shown to be opposed to it. Indeed I have had no choice but to act in this manner, for with the exception of the Coral Reefs, I cannot remember a single first-formed hypothesis which had not after a time to be given up or greatly modified.
(From The Autobiography of Charles Darwin [New York City: W.W. Norton and Company, Inc., 1958] p. 141)
What essentials of scientific process does Darwin express here?