CHAPTER VIII.

CLASSIFICATION AND DESCRIPTION OF THE MENTAL POWERS.

We now proceed to the classification and description of the mental powers.

Not only all writers on mental science, but the most common writers and speakers, recognize a general division of mental operations, which is expressed by the terms _intellect_, _feeling_, and _choice_. We _think_, we _feel_, and we _choose_. Even the young child learns to comprehend these three grand divisions of the mental phenomena.

To this most general division, in this work, are applied the terms _the intellectual powers, the susceptibilities_, and _the will_. These terms are selected because they are the most common ones.

THE INTELLECTUAL POWERS.

Under the general class of intellectual powers are arranged the following specific powers of mind:

Sensation, Perception, Conception, Memory, Imagination, Judgment, Abstraction, Attention, and Association.

_Sensation_ is a state of mind produced by material objects acting on the senses.

Thus, when light, which is considered as one kind of matter, affects the eye, the sensation of _sight_ is produced. When the perfume of a rose, which is another species of matter, affects the nostrils, the sensation of _smell_ is produced. When a bell or some musical instrument causes the air to vibrate on the drum of the ear, it causes the sensation of _sound_. When any sapid body is applied to the tongue, the sensation of _taste_ is caused. When the hand, or any part of the body, comes in contact with another body, the sensation of _touch_ is produced.

Thus it appears that the five senses are the organs of sensation, and that through their instrumentality material things operate upon the mind.

_Perception_ is a _sensation_ attended by the _belief of a cause_, and it is this additional circumstance alone which distinguishes perception from sensation.

If a person were asleep, and should suffer from the prick of a pin, or be disturbed by an unpleasant sound, these would be mere sensations, because the mind would not ascribe them to any cause. But if the person should waken, these sensations would immediately become perceptions, because they would be attended by the belief of some cause.

_Conception_ is a state of mind similar to perception, and differs from it in being less vivid, and in not being produced through the medium of the senses.

When we look at a tree, we have a _perception_ of this object. But the mind can also have an idea of this tree when removed from the sight, though the idea is not so vivid and distinct, nor have the senses any agency in producing it. The perfume of a rose, also, occasions another sensation; but when the rose is removed, so as not to affect the senses, we can still have a _conception_ of its perfume. The conception differs from the perception only in being less vivid, and in not being caused by a material object acting on the senses.

_Memory_ is either a conception or a perception, which is attended with a feeling of its resemblance to a past state of mind. It is this feeling of resemblance that is the only circumstance which distinguishes memory from conception.

Thus we may conceive of a tree without recognizing it as the particular idea of any tree we may have seen before; but if this is accompanied by a feeling of the resemblance of this idea to the one we always have when we see the tree that shadows the paternal roof, this conception becomes _memory_. If we conceive the form of a man without recognizing the resemblance of this idea to the perceptions we have when we see any particular man, this is a simple act of conception; but if we recognize in this object of conception the features of a dear friend, this act then becomes memory. Again, if we conceive of certain events and circumstances attending them without recognizing this combination as ever having existed in past experience, they are mere conceptions; but if we recognize in them the events and circumstances of past experience, conception becomes memory.

_Imagination_ is the power which the mind possesses of arranging our conceptions in new combinations. We can conceive objects as united together of which we never conceived before as thus united.

Thus, when we read the description of some picturesque scene in nature, the mind immediately groups together mountains, trees, brooks, cottages, and glens, forming a new combination of conceptions different from any scene we ever witnessed or conceived before. All the objects thus combined are conceptions; the act of arranging them is an act of the imagination.

_Judgment_ is the power which the mind possesses of _noticing relations_. A _relation_ is an idea obtained by observing one thing in connection with another. Thus, when we perceive one thing to be _longer_ than another, one thing to be _on_ another, or one thing to _belong_ to another--in all these cases the mind _notices relations_, or exercises the faculty of judgment. Thus, also, when we compare any action with the rule of duty in order to decide whether it is right or wrong, we exercise the same faculty. This act always is necessarily preceded by the comparison of one thing with another, in order to notice the relations.

_Abstraction_ is the power of noticing certain parts or qualities of any object, as distinct from other parts or qualities. Thus, when we notice the length of a bridge without attending to the breadth or color, or when we notice the height of a man without thinking of his character, we exercise the faculty of abstraction.

_Attention_ is the direction of the mind to any particular object or quality, from the interest which is felt in it, or in something connected with it. The degree of attention is always proportioned to the degree of interest felt in the object.

_Association_ is the power possessed by the mind of recalling ideas in the connections and relations in which they have existed in past experience. For example, when any two objects, such as a house and a tree, have often been observed together, the idea of one will ordinarily be attended by that of the other. If two events have often been united together in regard to the _time_ of their occurrence, such, for example, as thunder and lightning, the idea of one will usually be attended by the other.

In this work, the aim is to introduce no more of mental analysis than is needed for its main object. What is here introduced is not claimed as a complete presentation of all the mental phenomena.