=B. Feeling.=--Faulty concepts are not, however, the only causes for wrong judgments. It has been noted already that feeling enters largely as a factor in our conscious life. Man, therefore, in forming his judgments, is always in danger of being swayed by his feelings. Our likes and dislikes, in other words, interfere with our thinking, and prevent us from analysing our knowledge as we should. Instead, therefore, of striving to develop true concepts concerning men and events and basing our judgments upon these, we are inclined in many cases to allow our judgments to be swayed by mere feeling.
=C. Laziness.=--Indifference is likewise a common source of faulty judgments. To attend to the concept and discover its intension as a means for correct judgment evidently demands mental effort. Many people, however, prefer either to jump at conclusions or let others do their judging for them.
=Sound Judgments Based on Scientific Concepts.=--To be able to form correct judgments regarding the members of any class, however, the child should know, not only its common characteristics, but also the essential features which distinguish its members from those of co-ordinate classes. To know adequately the equilateral triangle, for instance, the pupil must know both the features which distinguish it from other triangles and also those in which it agrees with all triangles. To know fully the mentha family of plants, he must know both the characteristic qualities of the family and also those of the larger genus labiatae. From this it will be seen that a large share of school work must be devoted to building up scientific class notions in the minds of the pupils. Without this, many of their judgments must necessarily be faulty. To form such scientific concepts, however, it is necessary to relate one concept with another in more indirect ways than is done through the formation of judgments. This brings us to a consideration of _reasoning_, the third and last form of thinking.
=Nature of Reasoning.=--Reasoning is defined as a mental process in which the mind arrives at a new judgment by comparing other judgments. The mind, for instance, is in possession of the two judgments, "Stones are heavy" and "Flint is a stone." By bringing these two judgments under the eye of attention and comparing them, the mind is able to arrive at the new judgment, "Flint is heavy." Here the new judgment, expressing a relation between the notions, _flint_ and _heavy_, is supposed to be arrived at, neither by direct experience, nor by an immediate analysis of the concept _flint_, but more indirectly by comparing the other judgments. The judgment, or conclusion, is said, therefore, to be arrived at mediately, or by a process of reasoning. Reasoning is of two forms, deductive, or syllogistic, reasoning, and inductive reasoning.