THE CONCEPTS SERVE TO GROUP AND CLASSIFY.--But the somewhat complicated
form of classification just described did not come to man ready-made.
Someone had to _see_ the relationship existing among the myriads of
animals of a certain class, and group these together under the general
term _mammals_. Likewise with birds, reptiles, insects, and all the
rest. In order to accomplish this, many individuals of each class had to
be observed, the qualities common to all members of the class
discriminated from those not common, and the common qualities retained
as the measure by which to test the admission of other individuals into
this class. The process of classification is made possible by what the
psychologist calls the _concept_. The concept enables us to think
_birds_ as well as bluebirds, robins, and wrens; it enables us to think
_men_ as well as Tom, Dick, and Harry. In other words, _the concept lies
at the bottom of all thinking which rises above the seeing of the
simplest relations between immediately present objects_.
