fy objects and group individual things into classes, depends upon
its capacity to detect similarity and difference, or to make
comparisons. When the mind, in identifying objects, events, qualities,
etc., discovers certain relations between its various states, the
process is especially known as that of thinking. In its technical sense,
therefore, thought implies a more or less explicit apprehension of
relation.

=Thinking Involved in all Conscious States.=--It is evident, however,
that every mental process must involve thinking, or a grasping of
relations. When, by my merely touching an object, my mind perceives it
is an apple, this act of perception, as already seen, takes place
because elements of former experience come back as associated factors.
This implies, evidently, that the mind is here relating elements of its
past experience with the present touch sensation. Perception of external
objects, therefore, implies a grasping of relations. In the same way,
if, in having an experience to-day, one recognizes it as identical with
a former experience, he is equally grasping a relation. Every act of
memory, therefore, implies thinking. Thus in all forms of knowledge the
mind is apprehending relations; for no experience could have meaning
for the mind except as it is discriminated from other experiences. In
treating thinking as a distinct mental process, however, it is assumed
that the objects of sense perception, memory, etc., are known as such,
and that the mind here deals more directly with the relations in which
ideas stand one to another. As a mental process, thinking appears in
three somewhat distinct forms, known as conception, judgment, and
reasoning.

CONCEPTION

=The Abstract Notion.=--It was seen that at least in adult life, the
perception of any object, as this particular orange, horse, cow, etc.,
really includes a number of distinct images of quality synthesised into
the unity of a particular idea or experience. Because of this union of a
number of different sensible qualities in the notion of a single
individual, the mind may limit its attention upon a particular quality,
or characteristic, possessed by an object, and make this a distinct
problem of attention. Thus the mind is able to form such notions as
length, roundness, sweetness, heaviness, four-footedness, etc. When such
an attribute is thought of as something distinct from the object, the
mental image is especially known as an abstract idea, or no