Leaving out of view the Will, which is a simple homogeneous mental state, forming the link between feeling and action, and not admitting of subdivisions; our states of consciousness fall into two great classes--COGNITIONS and FEELINGS. COGNITIONS, or those modes of mind in which we are occupied with the _relations_ that subsist among our feelings, are divisible into four great sub-classes. _Presentative cognitions_; or those in which consciousness is occupied in localizing a sensation impressed on the organism--occupied, that is, with the relation between this presented mental state and those other presented mental states which make up our consciousness of the part affected: as when we cut ourselves. _Presentative-representative cognitions_; or those in which consciousness is occupied with the relation between a sensation or group of sensations and the representations of those various other sensations that accompany it in experience. This is what we commonly call perception--an act in which, along with certain impressions presented to consciousness, there arise in consciousness the ideas of certain other impressions ordinarily connected with the presented ones: as when its visible form and colour, lead us to mentally endow an orange with all its other attributes. _Representative cognitions_; or those in which consciousness is occupied with the relations among ideas or represented sensations: as in all acts of recollection. _Re-representative cognitions_; or those in which the occupation of consciousness is not by representation of special relations, that have before been presented to consciousness; but those in which such represented special relations are thought of merely as comprehended in a general relation--those in which the concrete relations once experienced, in so far as they become objects of consciousness at all, are incidentally represented, along with the abstract relation which formulates them. The ideas resulting from this abstraction, do not themselves represent actual experiences; but are symbols which stand for groups of such actual experiences--represent aggregates of representations. And thus they may be called re-representative cognitions. It is clear that the process of re-representation is carried to higher stages, as the thought becomes more abstract. FEELINGS, or those modes of mind in which we are occupied, not with the relations subsisting between our sentient states, but with the sentient states themselves, are divisible into four parallel sub-classes. _Presentative feelings_, ordinarily called sensations, are those mental states in which, instead of regarding a corporeal impression as of this or that kind, or as located here or there, we contemplate it in itself as pleasure or pain: as when eating.