y afterwards serve to arrange, or, as Dr. Whewell says, to
_connect_. They seem to be pre-existent; but this is only because the
mind keeps ever forming conceptions from the facts, which at the time
are before it, and then tentatively applies these conceptions (which it
is always remodelling, dropping some which are found not to suit
after-found facts, and generalising others by a further effort of
abstraction) as types of comparison for phenomena subsequently
presented to it; so that, being found in these later stages of the
comparison already in the mind, they appear in the character simply of
types, and not as being also themselves results of comparison. Really
they are always both; and the term _comparison_ expresses as well their
origin as (and this far more exactly than to _connect_ or to
_superinduce_) their function.

Dr. Whewell says that conceptions must be _appropriate_ and _clear_.
They must, indeed, be appropriate relatively to the purpose in view (for
appropriateness is only relative); but they cannot avoid being
appropriate (though one may be more so than another) if our comparison
of the objects has led to a conception corresponding to any real
agreement in the facts: the ancients' and schoolmen's conceptions were
often absolutely inappropriate, because grounded on only apparent
agreement. So, again, they must be _clear_ in the following sense; that
is to say, a _sufficient number_ of facts must have been _carefully
observed_, and accurately _remembered_. It is also a condition (and one
implied in the latter qualities) of clearness, that the conception
should be _determinate_, that is, that we should know precisely what
agreements we include in it, and never vary the connotation except
consciously.

Activity, carefulness, and accuracy in the observing and comparing
faculties are therefore needed; the first quality to produce
appropriateness, and the latter two, clearness. Moreover, _scientific
imagination_, i.e. the faculty of mentally arranging known elements into
new combinations, is necessary for forming true conceptions; and the
mind should be stored with previously acquired conceptions, kindred to
the subject of inquiry, since a comparison of the facts themselves often
fails to suggest the principle of their agreement; just as, in seeking
for anything lost, we often have to ask ourselves in what places it may
be hid, that we may search for it there.

CHAPTER III.

NAMING AS SUBSIDIARY TO