7. NOTE.--There are some nouns, such as _sun_, _moon_, _earth_,
which seem to be the names of particular individual objects, but which
are not called proper names.

[Sidenote: _Words naturally of limited application not proper._]

The reason is, that in proper names the intention is _to exclude_ all
other individuals of the same class, and fasten a special name to the
object considered, as in calling a city _Cincinnati_; but in the words
_sun_, _earth_, etc., there is no such intention. If several bodies
like the center of our solar system are known, they also are called
_suns_ by a natural extension of the term: so with the words _earth_,
_world_, etc. They remain common class names.


[Sidenote: _Names of ideas, not things._]

8. Abstract nouns are names of qualities, conditions, or actions,
considered abstractly, or apart from their natural connection.

When we speak of a _wise man_, we recognize in him an attribute or
quality. If we wish to think simply of that quality without describing
the person, we speak of the _wisdom_ of the man. The quality is still
there as much as before, but it is taken merely as a name. So
_poverty_ would express the condition of a poor person; _proof_ means
the act of proving, or that which shows a thing has been proved; and
so on.

Again, we may say, "_Painting_ is a fine art," "_Learning_ is hard to
acquire," "a man of _understanding_."