As we shall have occasion frequently to refer to these psychological terms it may be well to define them.
| Psychological Definition. | Logical Definition. |
| A sensation is the first and simplest mental result of the stimulation of an incarrying nerve. | A sensation is a vague, unlocalized mental product of the knowing mind. |
| A percept is a mental product which results from a consciousness of particular material things present to the sense. | A percept is a consciously localized group of sensations. |
| An image is a mental product which results from particular material things not present to the sense. | An image is a reproduced percept. |
| A concept is a representation in our minds answering to a general name. | A concept is a mental product arising from thinking many notions into one class. |
| A judgment is the result of asserting an agreement or disagreement between two ideas. | A judgment is the mental product arising from conjoining or disjoining notions. |
| An inference is a judgment derived from perceiving relations between other judgments. | An inference is a judgment derived from antecedent judgments. |
It is seen that the sensations furnish the raw material. Ignoring the few exceptions we may then say that a percept is a made-over group of sensations; a concept a thought-made group of percepts; a judgment a thought-made group of concepts; an inference a judgment derived from other judgments.
Developed thinking is first found in the concept, and as we study the thought products, “concept,” “judgment” and “inference,” the truth is forced upon us that thinking as a process aims to group the many into one.From many percepts is built the one concept, from two concepts is built the one judgment and from two judgments is built the one inference.[3]
Speaking figuratively, thinking is a matter of picking up the fragments along the shore of consciousness and tying them into bundles.
7. THOUGHT IN THE SENSATION AND PERCEPT.
So far in this discussion it has been assumed that there is no thinking involved in the sensation or the percept. There are good authorities, however, who insist on dignifying the sensation, even with a crude form of thinking. To illustrate: One may be reading an interesting novel. The mind is being entertained and ignores the activities of the objective world, yet we cannot say that the mind is dead to the world outside. There is a dim consciousness of certain noises without. These unlocalized sounds are sensations; but how is the mind able to recognize them as sounds or noises? To interpret the noises isit not necessary for the mind to affirm a connection between them and some past mental experience? Is it possible for the mind to know anything without establishing some kind of connection between the outside occurrence and an inner situation? If this is granted then in sensation there must be implicit thinking.
As the percept is a localized group of sensations then there must be involved in perception a more complex form of thinking, since in grouping sensations there is a recognition of connections.
If there is thinking in the sensation which is the simplest and lowest form of the knowing-mind then thinking conditions all knowledge and really is the basic elemental cell of all knowing.
On the other hand there are those who maintain that the sensation and percept are mere reflections of consciousness; the sensation being a reflected quality and the percept a reflected object. These mental situations come into being instantly—there is no time for thought and we all know that thought requires time. (“As quick as thought” is misleading, since light travels more rapidly by many times than the agencies of thought.)