F. In my opinion it is a grave and wise one. Moreover, I conceive that
the judicial calmness which so strongly characterises the whole book, the
absence of all passion, the air of extreme and anxious caution which
pervades it throughout, are rather the result of training and
artificially acquired self-restraint than symptoms of a cold and
unimpassioned nature; at any rate, whether the lawyer-like faculty of
swearing both sides of a question and attaching the full value to both is
acquired or natural in Darwin’s case, you will admit that such a habit of
mind is essential for any really valuable and scientific investigation.