The ideal reasoner, would, when he had once been shown a single fact
in all its bearings, deduce from it not only the chain of events which
led up to it but also the results which would follow from it. As Cuvier
could correctly describe a whole animal by the contemplation of a single
bone, so the observer who has thoroughly understood one link in a series
of incidents should be able to accurately state all the other ones, both
before and after. We have not yet grasped the results which the reason
alone can attain to. Problems may be solved in the study which have
baffled all those who have sought a solution by aid of their senses. To
carry the art, however, to its highest pitch, it is necessary that the
reasoner should be able to utilize all the facts which have come to his
knowledge; and this in itself implies, as you will readily see, a
possession of all knowledge, which, even in these days of free education
and encyclopedias, is a somewhat rare accomplishment. It is not so
impossible, however, that a man should possess all knowledge which is
likely to be useful to him in his work, and this I have endeavored in
my case to do.
-- Sherlock Holmes
