Sensory Ideas ...

Sensory Ideas : These are simple phenomena in the soul which result from the effects of the relations between the sensory organs and material realities, such as images of scenery which we see with the eyes, or sounds which we hear with the ears. The subsistence of this kind of idea depends on the subsistence of relations with the external world, and after being cut off from contact with the external world they vanish in a short period of time (such as one tenth of a second).

Imaginary Ideas : These are simple specific phenomena in the soul which are subsequent results of sensory ideas and links with the external world. But their subsistence does not depend upon links with the external world, such as the mental image of a view of a garden which remains in the mind even after the eyes are closed, and may be recalled even after years have gone by.

Ideas of Prehension ( Wahm ) :1 Many philosophers have mentioned another kind of particular idea which is related to particular meanings, and which is exemplified by the feeling of enmity which some animals have for some others, a feeling which requires them to flee. Some philosophers have extended this term to cover particular meanings in general, including the feelings of affection and enmity of man.. Undoubtedly, universal concepts of affection and enmity are a kind of universal ideas.

They cannot be counted as types of particular ideas. The perception of particular affections and enmities in the perceiver himself, that is the affection which a person finds in himself for another, or the enmity which he feels in himself for another, is really a kind of presentational knowledge of qualities of the soul, and we cannot count them as kinds of acquired knowledge.

Our feeling of another person’s enmity, in fact, is not a direct feeling without intermediary, but it is a comparison between a state which a man has found within himself and attributed to another person in a similar condition. But judgments about the perceptions of animals require another discussion which we do not have the opportunity to pursue further here.

What can be accepted as a kind of specific idea is an idea which results from states of the soul, and is apt to be recalled, and which are like imaginary ideas with relation to sensory ideas, such as remembering a specific fear that appeared at a certain moment, or a specific affection which existed at a specific moment.