ruction.

We have seen that both the search for causes and the examination
of means lead into the field of theory; that is, into the field of
universal truth, which does not proceed solely from the case immediately
under examination. If there is a theory which can be used, then the
critical consideration will appeal to the proofs there afforded, and the
examination may there stop. But where no such theoretical truth is to be
found, the inquiry must be pushed up to the original elements. If this
necessity occurs often, it must lead the historian (according to a
common expression) into a labyrinth of details. He then has his hands
full, and it is impossible for him to stop to give the requisite
attention everywhere; the consequence is, that in order to set bounds to
his investigation, he adopts some arbitrary assumptions which, if they
do not appear so to him, do so to others, as they are not evident in
themselves or capable of proof.

A sound theory is therefore an essential foundation for criticism, and
it is impossible for it, without the assistance of a sensible theory,
to attain to that point at which it commences chiefly to be instructive,
that is, where it becomes demonstration, both convincing and sans
re'plique.

But it would be a visionary hope to believe in the possibility of a
theory applicable to every abstract truth, leaving nothing for criticism
to do but to place the case under its appropriate law: it would be
ridiculous pedantry to lay down as a rule for criticism that it must
always halt and turn round on reaching the boundaries of sacred theory.
The same spirit of analytical inquiry which is the origin of theory must
also guide the critic in his work; and it can and must therefore happen
that he strays beyond the boundaries of the province of theory and
elucidates those points with which he is more particularly concerned. It
is more likely, on the contrary, that criticism would completely fail
in its object if it degenerated into a mechanical application of theory.
All positive results of theoretical inquiry, all principles, rules, and
methods, are the more wanting in generality and positive truth the more
they become positive doctrine. They exist to offer themselves for use as
required, and it must always be left for judgment to decide whether
they are suitable or not. Such results of theory must never be used in
criticism as rules or norms for a standard, but in the same way as the
person acting sh