questions which underlie the discussion, apart from
the more personal phases of the dispute, should be thoroughly
discussed. And if it were possible to have controversy without
bitterness in human affairs, I should be disposed, for the general
good, to use to both of the eminent antagonists the famous phrase of a
late President of the French Chamber--"_Tape dessus._"

No profound acquaintance with the history of science is needed to
produce the conviction, that the advancement of natural knowledge has
been effected by the successive or concurrent efforts of men, whose
minds are characterised by tendencies so opposite that they are forced
into conflict with one another. The one intellect is imaginative and
synthetic; its chief aim is to arrive at a broad and coherent
conception of the relations of phenomena; the other is positive,
critical, analytic, and sets the highest value upon the exact
determination and statement of the phenomena themselves.

If the man of the critical school takes the pithy aphorism "Melius
autem est naturam secare quam abstrahere"[1] for his motto, the
champion of free speculation may retort with another from the same
hand, "Citius enim emergit veritas e falsitate quam e confusione;"[2]
and each may adduce abundant historical proof that his method has
contributed as much to the progress of knowledge as that of his rival.
Every science has been largely indebted to bold, nay, even to wild
hypotheses, for the power of ordering and grasping the endless details
of natural fact which they confer; for the moral stimulus which arises
out of the desire to confirm or to confute them; and last, but not
least, for the suggestion of paths of fruitful inquiry, which, without
them, would never have been followed. From the days of Columbus and
Kepler to those of Oken, Lamarck, and Boucher de Perthes, Saul, who,
seeking his father's asses, found a kingdom, is the prototype of many
a renowned discoverer who has lighted upon verities while following
illusions, which, had they deluded lesser men, might possibly have
been considered more or less asinine.

On the other hand, there is no branch of science which does not owe at
least an equal obligation to those cool heads, which are not to be
seduced into the acceptance of symmetrical formulae and bold
generalisations for solid truths because of their brilliancy and
grandeur; to the men who cannot overlook those small exceptions and
insignificant residual phenomena