ind that if I should never again see a particular horse, I should
yet always be able to think accurately of a horse.

Concepts are of two kinds--concrete and abstract.

A _concrete concept_, or concrete idea (for concept and idea are
interchangeably used), is an idea of a particular object or quality.

Examples: This wine-sap apple (object concept).
This sweet orange (quality concept).

An _abstract concept_, or abstract idea, is a mental reproduction of a
quality or an object dissociated from any particular setting or
particular experience.

Abstract ideas are of two kinds. We speak of them as _abstract object
concepts_ and as _abstract quality concepts_. An _abstract object
concept_ we might call a generalized idea, an idea comprehending all
objects having certain things in common.

Example: My idea of animal includes many scores of very different
individual animals, but they all have bodies and heads and extremities.
They all have some kind of digestive apparatus; they breathe, and can
move.

An _abstract quality concept_ is easier to think than to explain. It is
as though the mind in considering a multitude of different objects found
a certain quality common to many of them, and it "abstracted," _i. e._,
drew this particular quality, and only this, from them all, and then
imagined it as a something in itself which it calls _redness_, or
_whiteness_, or _goodness_. Thereafter, whenever it finds something like
it anywhere else again it says, "That is like my redness." So I call it
"red." In other words, consciousness thereafter can determine in a newly
discovered object something it knows well merely because that something
corresponds to a representation which experience and memory have already
formed.

These comprehensive concepts, or _universals_, as some psychologists
term them, the mind, having pieced together from experience and memory,
holds as independent realities, not primarily belonging to _this_ or
_that_, but lending themselves to this or that. For example: My mind
says "white," and sees white in some object. But I see the white only
because my mind has a quality concept, _whiteness_. This outside object
corresponds to my concept. I recognize the likeness and call it "white."

I speak of goodness, or purity, of benevolence; or of fulness,
emptiness, scantiness. There is no object or quality in the outside
world I can say is goodness, or fulness. But I do see things in the
external