_Perception_ is that faculty of the Mind which interprets the material presented to it by the senses. It is the power whereby we gain our knowledge of the external world, as reported to us by the channels of sense. Through Perception we are able to form ideas and mental images, which in turn lead to thoughts. The objects of which we become conscious through Perception are called _percepts_, which form the bases of what we call _concepts_, or ideas. _Understanding_ is that faculty of the Mind by the means of which we are able intelligently to compare the objects presented to it by Perception, and by which we separate them into parts by analysis, or to combine them into greater classes, or wholes, by synthesis. It produces ideas, both abstract and general; also concepts of truths, laws, principles, causes, etc. There are several sub-phases of Understanding, which are known as: Abstraction, Conception or Generalization, or Judgment and Reasoning, respectively, which are explained as follows: _Abstraction_ is that faculty of the Mind which enables it to abstract, or draw off, and consider apart from an object, a particular _quality_ or _property_ of an object, thus making of the quality or property a distinct object of thought apart from the original object. Thus are the _abstract ideas_ of _sweetness_, _color_, _hardness_, _courage_, _beauty_, etc., which we have abstracted or _drawn off_ from their original associations, either for the purpose of putting them out of sight and consideration, or else to view and consider them by themselves. No one ever tasted "sweetness" although one may have tasted _sweet things_; no one ever saw "red," although one may have seen _red things_; no one ever saw, heard, tasted or felt "courage" in another, although one may have seen _courageous people_. Abstract ideas are merely the mental conception of _qualities_ or _properties_ divorced from their associated objects by Abstraction. _Conception_ or Generalization is that faculty of the Mind by which it forms and groups together several particular ideas in the form of _a general idea_. By the processes of Conception we form _classes_ or _generalizations_ from particular ideas arising from our _percepts_. First, we _perceive_ things; then we _compare_ them with each other; then we abstract their particular qualities, which are not common to the several objects; then we _generalize_ them according to their resemblances; then we _name_ the generalized concept. From these combined processes we form a Concept, or _general idea_ of the class of things to which the particular things belong. Thus from subjecting a number of cows to this process, we arrive at the general Concept of "Cow." This general Concept includes all the qualities and properties _common to all cows_, while omitting those which are not common to the class. Or, we may form a concept of Napoleon Bonaparte, by combining his several qualities and properties and thus form a _general idea_ of the man.