"To whom all scenes of Europe homage owe."

A misunderstanding of the proper use of theory is among the prevalent
scientific errors of the present day. Among one set of men of
considerable intelligence, but who are not habitually conversant with
physical science, there is a general tendency to despise theory. This
contempt appears to rest on somewhat plausible grounds; as an instance
of it, we may take the following passage from the fitful writings of
Mr Carlyle:--"Hardened round us, encasing wholly every notion we form,
is a wrappage of traditions, hearsays, mere words: we call that fire
of the black thunder-cloud electricity, and lecture learnedly about
it, and grind the like of it out of glass and silk, but what is it?
Whence comes it? Where goes it?"[26]

[26] Carlyle on Hero Worship.

However the experienced philosopher may be convinced that _in
themselves_ theories are nothing--that they are but collations of
phenomena under a generic formula, which is useful only inasmuch as it
groups these phenomena; yet it is difficult to see how, without these
imperfect generalizations, any mind can retain the endless variety of
facts and relations which every branch of science presents; still
less, how these can be taught, learned, reasoned upon, or used. How
could the facts of geology be recollected, or how, indeed, could they
constitute a science without reference to some real or supposed bond
of union, some aqueous or igneous theory? How could two chemists
converse on chemistry without the use of the term affinity, and the
theoretical conception it involves? How could a name be applied, or a
nomenclature adopted, without that imperfect, or more or less perfect
grouping of facts, which involves theory? As far as we can recollect,
all the alterations of nomenclature which have been introduced, or
attempted, proceed upon some alteration of theory.

If not theory but hypothesis be objected to--not the imperfect
generalization of phenomena, but a gratuitous assumption for the sake
of collating them, this, although ground which should be trodden more
cautiously, appears in certain cases unavoidable; in fact, is scarcely
separable from theory. Had men not "lectured learnedly" about the two
_fluids_ of electricity, we should not now possess many of the
discoveries with which this science is enriched, although we do not,
and probably never shall, know what electricity is.

On the other hand, among professed physical philos