n inconspicuous, or have not
happened to occur in the region inhabited by those who speak a
particular language; and even things recognised and named may have been
very superficially examined, and therefore wrongly classed, as when a
whale or porpoise is called a fish, or a slowworm is confounded with
snakes. A scientific classification, on the other hand, aims at the
utmost comprehensiveness, ransacking the whole world from the depths of
the earth to the remotest star for new objects, and scrutinising
everything with the aid of crucible and dissecting knife, microscope and
spectroscope, to find the qualities and constitution of everything, in
order that it may be classed among those things with which it has most
in common and distinguished from those other things from which it
differs. A scientific classification continually grows more
comprehensive, more discriminative, more definitely and systematically
coherent. Hence the uses of classification may be easily perceived.

Sec. 2. The first use of classification is the better understanding of the
facts of Nature (or of any sphere of practice); for understanding
consists in perceiving and comprehending the likeness and difference of
things, in assimilating and distinguishing them; and, in carrying out
this process systematically, new correlations of properties are
continually disclosed. Thus classification is closely analogous to
explanation. Explanation has been shown (chap. xix. Sec. 5) to consist in
the discovery of the laws or causes of changes in Nature; and laws and
causes imply similarity, or like changes under like conditions: in the
same way classification consists in the discovery of resemblances in the
things that undergo change. We may say (subject to subsequent
qualifications) that Explanation deals with Nature in its dynamic,
Classification in its static aspect. In both cases we have a feeling of
relief. When the cause of any event is pointed out, or an object is
assigned its place in a system of classes, the gaping wonder, or
confusion, or perplexity, occasioned by an unintelligible thing, or by a
multitude of such things, is dissipated. Some people are more than
others susceptible of this pleasure and fastidious about its purity.

A second use of classification is to aid the memory. It strengthens
memory, because one of the conditions of our recollecting things is,
that they resemble what we last thought of; so that to be accustomed to
study and think o