In addition to the psychological and spiritual factors associated with his
rejection of Christianity, this may also reflect the illness that affected
most of Darwin's life after the voyage on the Beagle. There remains debate
as to just what it was, but it sounds as though it would have been
conducive to depression.
There can be a danger in science of losing your appreciation of creation.
Ironically, Dawkins has apparently recognized this as a problem in his
latest book (I have only seen reviews, not the original), even though he
does not acknowledge that it is created. "Familiarity breeds contempt" is
the basic problem-having seen something so often makes it easy to ignore,
just as we are often not thankful for God's everyday provisions. Finding
out more about how God runs the universe should give a new aspect to our
praise rather than dampen it.